LT1787/LT1787HV Precision, High Side Current Sense Amplifiers FEATURES DESCRIPTIOU ■ Input Offset Voltage: 75(cid:181)V (Max) The LT®1787 is a complete micropower precision high ■ 60V Supply Operation (LT1787HV) side current sense amplifier. The LT1787 monitors bidi- ■ 12-Bit Dynamic Range rectional currents via the voltage across an external sense ■ Operating Current: 60(cid:181)A resistor. A current or voltage output indicates the direction ■ User-Selectable External Sense Resistor and magnitude of the sense current. The LT1787 delivers ■ Bidirectional High Side Current Sensing greater than a 12-bit dynamic range with ultralow 40(cid:181)V ■ Unidirectional or Bidirectional Output input offset voltage compared to a typical 250mV full- ■ Input Noise Filtering scale input voltage. A fixed gain of 8 is set by onboard ■ –40(cid:176)C to 125(cid:176)C Operating Temperature Range precision resistors. Input signal filtering is easily imple- ■ Available in 8-Lead SO and MSOP Packages mented with a capacitor between the FIL– and FIL+ pins. The LT1787HV operates from 2.5V to 60V total supply APPLICATIOUS voltage and the LT1787 operates from 2.5V to 36V total supply voltage. Both versions have a PSRR in excess of ■ Battery Monitoring 120dB. The LT1787/LT1787HV draw only 60(cid:181)A and are ■ Power Monitoring available in 8-lead SO and MSOP packages. ■ Portable Phones , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. ■ Cellular Phones ■ Portable Test/Measurement Systems ■ Battery-Operated Systems TYPICAL APPLICATIOU 12-Bit Dynamic Resolution Unidirectional Output into LTC®1286 ADC Input Offset Voltage vs Supply Voltage RSENSE 50 TO I = 100A 0.0016Ω 40 LOAD 1 FIL– FIL+ 8 2.5V TO 60V V)(cid:181) 30 LT1787HV E ( 20 2 VS– VS+ 7 R1 C1 TAG 10 5V L 3 DNC VBIAS 6 15k 1(cid:181)F T VO 0 E ROUT FS–10 4 VEE 2V0OkUT 5 +–INIVNREFLTCGV1NC2DC86DCOCLUSKT TO (cid:181)P INPUT OF––2300 C2 –40 VOUT = VBIAS + (8 • ILOAD • RSENSE) 0.1(cid:181)F LT1634-1.25 1787 TA01 –50 0 10 20 30 40 50 60 TOTAL SUPPLY VOLTAGE (V) 1787 TA01b 1787fc 1

LT1787/LT1787HV ABSOLUTE WMAXIWMUWM RATINUGS (Notes 1, 2) Differential Sense Voltage......................................–10V Specified Temperature Range (Note 4) Total Supply Voltage (LT1787)................................ 40V LT1787C............................................. –40(cid:176)C to 85(cid:176)C Total Supply Voltage (LT1787HV) ........................... 65V LT1787I.............................................. –40(cid:176)C to 85(cid:176)C Output Voltage.....................(V – 0.3V) to (V + 35V) LT1787H .......................................... –40(cid:176)C to 125(cid:176)C EE EE Output Bias Voltage.............(V – 0.3V) to (V + 35V) Storage Temperature Range..................–65(cid:176)C to 150(cid:176)C EE EE Operating Temperature Range (Note 3) Lead Temperature (Soldering, 10 sec)..................300(cid:176)C LT1787C............................................. –40(cid:176)C to 85(cid:176)C LT1787I.............................................. –40(cid:176)C to 85(cid:176)C LT1787H .......................................... –40(cid:176)C to 125(cid:176)C PACKAGE/ORDER IUNFORWMATIOUN TOP VIEW TOP VIEW FIL– 1 8 FIL+ FVILS–– 12 87 FVISL++ VS– 2 7 VS+ DNC* 3 6 VBIAS DNC* 3 6 VBIAS VEE 4 5 VOUT VEE 4 5 VOUT MS8 PACKAGE 8-LEAD PLASTIC MSOP S8 PACKAGE * DO NOT CONNECT 8-LEAD PLASTIC SO TJMAX = 150(cid:176)C, θJA = 250(cid:176)C/W * DO NOT CONNECT TJMAX = 150(cid:176)C, θJA = 190(cid:176)C/W ORDER PART NUMBER MS8 PART MARKING ORDER PART NUMBER S8 PART MARKING LT1787CMS8 LTGM LT1787CS8 1787 LT1787IMS8 LTGN LT1787IS8 1787I LT1787HVCMS8 LTKJ LT1787HS8 1787H LT1787HVIMS8 LTKK LT1787HVCS8 1787HV LT1787HVIS8 787HVI LT1787HVHS8 787HVH Order Options Tape and Reel: Add #TR Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF Lead Free Part Marking: http://www.linear.com/leadfree/ Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS (Note 5) The ● denotes the specifications which apply over the temperature range 0(cid:176)C ≤ TA ≤ 70(cid:176)C, otherwise specifications are at TA = 25(cid:176)C. Total supply = (V – – V ) = 2.5V to 36V (LT1787C), 2.5V to 60V (LT1787HVC) unless otherwise specified. S EE SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V –, V + Sense Amplifier Supply Voltage Single Supply Operation (LT1787) ● 2.5 36 V S S Single Supply Operation (LT1787HV) ● 2.5 60 V VSENSE Input Sense Voltage Full Scale VSENSE = VS+ – VS–, VS = 10V, VBIAS = 5V, AV = 8 –10% ● 500 mV VOS Input Offset Voltage (S8) IOUT = 0, VS Supply = 5V –75 –40 75 (cid:181)V 0(cid:176)C ≤ TA ≤ 70(cid:176)C ● –135 135 (cid:181)V IOUT = 0 (LT1787) –100 100 (cid:181)V 0(cid:176)C ≤ TA ≤ 70(cid:176)C ● –160 160 (cid:181)V IOUT = 0 (LT1787HV) –100 100 (cid:181)V 0(cid:176)C ≤ TA ≤ 70(cid:176)C ● –160 160 (cid:181)V 1787fc 2

LT1787/LT1787HV ELECTRICAL CHARACTERISTICS (Note 5) The ● denotes the specifications which apply over the temperature range 0(cid:176)C ≤ TA ≤ 70(cid:176)C, otherwise specifications are at TA = 25(cid:176)C. Total supply = (V – – V ) = 2.5V to 36V (LT1787C), 2.5V to 60V (LT1787HVC) unless otherwise specified. S EE SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Input Offset Voltage (MS8) IOUT = 0, VS Supply = 5V –125 –40 125 (cid:181)V 0(cid:176)C ≤ TA ≤ 70(cid:176)C ● –230 230 (cid:181)V IOUT = 0 (LT1787) –150 150 (cid:181)V 0(cid:176)C ≤ TA ≤ 70(cid:176)C ● –250 250 (cid:181)V IOUT = 0 (LT1787HV) –150 150 (cid:181)V 0(cid:176)C ≤ TA ≤ 70(cid:176)C ● –250 250 (cid:181)V VOS TC Temperature Coefficient of VOS VS Supply = 5V (Note 6) ● 0.5 2 (cid:181)V/(cid:176)C I No-Load Output Current Error V = 0V 4 nA OUT(O) SENSE VOUT(O) No-Load Output Voltage Error VSENSE = 0V, VS Supply = 5V –600 600 (cid:181)V (S8) 0(cid:176)C ≤ TA ≤ 70(cid:176)C ● –1080 1080 (cid:181)V No-Load Output Voltage Error VSENSE = 0V, VS Supply = 5V –1000 1000 (cid:181)V (MS8) 0(cid:176)C ≤ TA ≤ 70(cid:176)C ● –1840 1840 (cid:181)V gm Tranconductance, IOUT/VSENSE –VSENSE = 10mV, 50mV, 100mV, 150mV, 250mV, 400 (cid:181)A/V V Supply = Total Supply + |V | S SENSE AV Gain, VOUT/VSENSE –VSENSE = 100mV, VS Supply = 5V ● 7.76 8 8.24 V/V Output Voltage Gain Error –VSENSE = 100mV, VS Supply = 5V ● –3 1 3 % V PSRR V Supply Rejection Ratio V = 0V, V Supply = 2.5V to 36V (LT1787) ● 120 135 dB S S SENSE S V = 0V, V Supply = 2.5V to 60V (LT1787HV) ● 120 135 dB SENSE S V PSRR Negative Supply Rejection Ratio V = 0V, V Supply = 15V, V = 0V, ● 100 130 dB EE SENSE S BIAS V = –1V to –15V (LT1787) EE V = 0V, V Supply = 40V, V = 0V, ● 100 130 dB SENSE S BIAS V = –1V to –15V (LT1787HV) EE ∆VOS Change in Input Offset Voltage VSENSE = 0V, VS Supply = 36V, VBIAS = 0.5V to 25V (LT1787) ● 100 130 dB ∆VBIAS with Change in VBIAS Voltage VSENSE = 0V, VS Supply = 60V, VBIAS = 0.5V to 25V (LT1787HV) ● 100 130 dB IS+(O) Positive Input Sense Current VSENSE = 0V ● 10 20 (cid:181)A IS–(O) Negative Input Sense Current VSENSE = 0V ● 50 100 (cid:181)A IEE(O) Negative Supply Current VSENSE = 0V ● 60 120 (cid:181)A IOUT Output Current VSENSE = –128mV –50 (cid:181)A VOUT Output Voltage VSENSE = –128mV, VS+ ≥ 3.3V VBIAS –1.024 V Ripple Rejection VS+ = VS– = 20V, ∆VS Supply = 1V, f = 1kHz ● 80 88 dB V Minimum Output Voltage V = 0V, V = 0V 30 45 mV OMIN SENSE BIAS V = V + – V – = –128mV, V = 0V 10 mV SENSE S S BIAS V = 0V, V = 0V ● 30 49 mV SENSE BIAS V = V + – V – = –128mV, V = 0V 10 mV SENSE S S BIAS Unipolar Output V = 2mV, V = 0V 32 50 mV SENSE BIAS Saturation Voltage V = 4mV, V = 0V 38 55 mV SENSE BIAS V = 5mV, V = 0V 43 60 mV SENSE BIAS V = 6mV, V = 0V 49 65 mV SENSE BIAS V = 2mV, V = 0V ● 32 54 mV SENSE BIAS V = 4mV, V = 0V ● 38 59 mV SENSE BIAS V = 5mV, V = 0V ● 43 64 mV SENSE BIAS V = 6mV, V = 0V ● 49 69 mV SENSE BIAS V Maximum Output Voltage V + – 0.75 V OMAX S RG1A, RG2A Input Gain-Setting Resistor Pin 1 to Pin 2, Pin 7 to Pin 8 1.25 kΩ ROUT Output Resistor Pin 5 to Pin 6 20 kΩ 1787fc 3

LT1787/LT1787HV ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the temperature range –40(cid:176)C ≤ TA ≤ 85(cid:176)C, otherwise specifications are at TA = 25(cid:176)C. Total supply = (VS– – VEE) = 2.5V to 36V (LT1787I), 2.5V to 60V (LT1787HVI) unless otherwise specified. (Note 5) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V –, V + Sense Amplifier Supply Voltage Single Supply Operation (LT1787) ● 2.5 36 V S S Single Supply Operation (LT1787HV) ● 2.5 60 V VSENSE Input Sense Voltage Full Scale VSENSE = VS+ – VS–, VS = 10V, VBIAS = 5V, AV = 8 –10% ● 500 mV VOS Input Offset Voltage (S8) IOUT = 0, VS Supply = 5V –75 –40 75 (cid:181)V –40(cid:176)C ≤ TA ≤ 85(cid:176)C ● –200 200 (cid:181)V IOUT = 0 (LT1787) –100 100 (cid:181)V –40(cid:176)C ≤ TA ≤ 85(cid:176)C ● –225 225 (cid:181)V IOUT = 0 (LT1787HV) –100 100 (cid:181)V –40(cid:176)C ≤ TA ≤ 85(cid:176)C ● –225 225 (cid:181)V Input Offset Voltage (MS8) IOUT = 0, VS Supply = 5V –125 –40 125 (cid:181)V –40(cid:176)C ≤ TA ≤ 85(cid:176)C ● –250 250 (cid:181)V IOUT = 0 (LT1787) –150 150 (cid:181)V –40(cid:176)C ≤ TA ≤ 85(cid:176)C ● –280 280 (cid:181)V IOUT = 0 (LT1787HV) –150 150 (cid:181)V –40(cid:176)C ≤ TA ≤ 85(cid:176)C ● –280 280 (cid:181)V VOS TC Temperature Coefficient of VOS VS Supply = 5V (Note 6) ● 0.5 2 (cid:181)V/(cid:176)C I No-Load Output Current Error V = 0V 4 nA OUT(O) SENSE VOUT(O) No-Load Output Voltage Error VSENSE = 0V, VS Supply = 5V –600 600 (cid:181)V (S8) –40(cid:176)C ≤ TA ≤ 85(cid:176)C ● –1600 1600 (cid:181)V No-Load Output Voltage Error VSENSE = 0V, VS Supply = 5V –1000 1000 (cid:181)V (MS8) –40(cid:176)C ≤ TA ≤ 85(cid:176)C ● –2000 2000 (cid:181)V gm Tranconductance, IOUT/VSENSE –VSENSE = 10mV, 50mV, 100mV, 150mV, 250mV, 400 (cid:181)A/V V Supply = Total Supply + |V | S SENSE AV Gain, VOUT/VSENSE –VSENSE = 100mV, VS Supply = 5V ● 7.76 8 8.24 V/V Output Voltage Gain Error –VSENSE = 100mV, VS Supply = 5V ● –3 1 3 % V PSRR V Supply Rejection Ratio V = 0V, V Supply = 2.5V to 36V (LT1787) ● 120 135 dB S S SENSE S V = 0V, V Supply = 2.5V to 60V (LT1787HV) ● 120 135 dB SENSE S V PSRR Negative Supply Rejection Ratio V = 0V, V Supply = 15V, V = 0V, ● 100 130 dB EE SENSE S BIAS V = –1V to –15V (LT1787) EE V = 0V, V Supply = 40V, V = 0V, ● 100 130 dB SENSE S BIAS V = –1V to –15V (LT1787HV) EE ∆VOS Change in Input Offset Voltage VSENSE = 0V, VS Supply = 36V, VBIAS = 0.5V to 25V (LT1787) ● 100 130 dB ∆VBIAS with Change in VBIAS Voltage VSENSE = 0V, VS Supply = 60V, VBIAS = 0.5V to 25V (LT1787HV) ● 100 130 dB IS+(O) Positive Input Sense Current VSENSE = 0V ● 10 20 (cid:181)A IS–(O) Negative Input Sense Current VSENSE = 0V ● 50 100 (cid:181)A IEE(O) Negative Supply Current VSENSE = 0V ● 60 120 (cid:181)A IOUT Output Current VSENSE = –128mV –50 (cid:181)A VOUT Output Voltage VSENSE = –128mV, VS+ ≥ 3.3V VBIAS –1.024 V Ripple Rejection VS+ = VS– = 20V, ∆VS Supply = 1V, f = 1kHz ● 80 88 dB V Minimum Output Voltage V = 0V, V = 0V 30 45 mV OMIN SENSE BIAS V = V + – V – = –128mV, V = 0V 10 mV SENSE S S BIAS V = 0V, V = 0V ● 30 51 mV SENSE BIAS V = V + – V – = –128mV, V = 0V 10 mV SENSE S S BIAS 1787fc 4

LT1787/LT1787HV ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the temperature range –40(cid:176)C ≤ TA ≤ 85(cid:176)C, otherwise specifications are at TA = 25(cid:176)C. Total supply = (VS– – VEE) = 2.5V to 36V (LT1787I), 2.5V to 60V (LT1787HVI) unless otherwise specified. (Note 5) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Unipolar Output V = 2mV, V = 0V 32 50 mV SENSE BIAS Saturation Voltage V = 4mV, V = 0V 38 55 mV SENSE BIAS V = 5mV, V = 0V 43 60 mV SENSE BIAS V = 6mV, V = 0V 49 65 mV SENSE BIAS V = 2mV, V = 0V ● 32 56 mV SENSE BIAS V = 4mV, V = 0V ● 38 61 mV SENSE BIAS V = 5mV, V = 0V ● 43 66 mV SENSE BIAS V = 6mV, V = 0V ● 49 71 mV SENSE BIAS V Maximum Output Voltage V + – 0.75 V OMAX S RG1A, RG2A Input Gain-Setting Resistor Pin 1 to Pin 2, Pin 7 to Pin 8 1.25 kΩ ROUT Output Resistor Pin 5 to Pin 6 20 kΩ The ● denotes the specifications which apply over the temperature range –40(cid:176)C ≤ TA ≤ 125(cid:176)C, otherwise specifications are at TA = 25(cid:176)C. Total supply = (VS– – VEE) = 2.5V to 36V (LT1787H), 2.5V to 60V (LT1787HVH) unless otherwise specified. (Note 5) V –, V + Sense Amplifier Supply Voltage Single Supply Operation (LT1787H) ● 2.5 36 V S S Single Supply Operation (LT1787HVH) ● 2.5 60 V VSENSE Input Sense Voltage Full Scale VSENSE = VS+ – VS–, VS = 10V, VBIAS = 5V, AV = 8 –10% ● 500 mV VOS Input Offset Voltage IOUT = 0, VS Supply = 5V –75 –40 75 (cid:181)V –40(cid:176)C ≤ TA ≤ 125(cid:176)C ● –400 400 (cid:181)V IOUT = 0 (LT1787H) –100 100 (cid:181)V –40(cid:176)C ≤ TA ≤ 125(cid:176)C ● –550 550 (cid:181)V IOUT = 0 (LT1787HVH) –100 100 (cid:181)V –40(cid:176)C ≤ TA ≤ 125(cid:176)C ● –550 550 (cid:181)V VOS TC Temperature Coefficient of VOS VS Supply = 5V (Note 6) ● 0.5 4 (cid:181)V/(cid:176)C I No-Load Output Current Error V = 0V 4 nA OUT(O) SENSE VOUT(O) No-Load Output Voltage Error VSENSE = 0V, VS Supply = 5V –600 600 (cid:181)V –40(cid:176)C ≤ TA ≤ 125(cid:176)C ● –3200 3200 (cid:181)V gm Tranconductance, IOUT/VSENSE –VSENSE = 10mV, 50mV, 100mV, 150mV, 250mV, 400 (cid:181)A/V V Supply = Total Supply + |V | S SENSE AV Gain, VOUT/VSENSE –VSENSE = 100mV, VS Supply = 5V ● 7.76 8 8.24 V/V Output Voltage Gain Error –VSENSE = 100mV, VS Supply = 5V ● –3 1 3 % V PSRR V Supply Rejection Ratio V = 0V, V Supply = 2.5V to 36V (LT1787H) ● 100 130 dB S S SENSE S V = 0V, V Supply = 2.5V to 60V (LT1787HVH) ● 100 130 dB SENSE S V PSRR Negative Supply Rejection Ratio V = 0V, V Supply = 15V, V = 0V, ● 100 130 dB EE SENSE S BIAS V = –1V to –15V (LT1787H) EE V = 0V, V Supply = 40V, V = 0V, ● 100 130 dB SENSE S BIAS V = –1V to –15V (LT1787HVH) EE ∆VOS Change in Input Offset Voltage VSENSE = 0V, VS Supply = 36V, VBIAS = 0.5V to 25V (LT1787H) ● 100 130 dB ∆VBIAS with Change in VBIAS Voltage VSENSE = 0V, VS Supply = 60V, VBIAS = 0.5V to 25V (LT1787HVH) ● 100 130 dB IS+(O) Positive Input Sense Current VSENSE = 0V ● 10 25 (cid:181)A IS–(O) Negative Input Sense Current VSENSE = 0V ● 50 115 (cid:181)A IEE(O) Negative Supply Current VSENSE = 0V ● 60 140 (cid:181)A IOUT Output Current VSENSE = –128mV –50 (cid:181)A VOUT Output Voltage VSENSE = –128mV, VS+ ≥ 3.3V VBIAS –1.024 V Ripple Rejection VS+ = VS– = 20V, ∆VS Supply = 1V, f = 1kHz ● 80 88 dB 1787fc 5

LT1787/LT1787HV ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the temperature range –40(cid:176)C ≤ TA ≤ 125(cid:176)C, otherwise specifications are at TA = 25(cid:176)C. Total supply = (VS– – VEE) = 2.5V to 36V (LT1787H), 2.5V to 60V (LT1787HVH) unless otherwise specified. (Note 5) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V Minimum Output Voltage V = 0V, V = 0V 30 45 mV OMIN SENSE BIAS V = V + – V – = –128mV, V = 0V 10 mV SENSE S S BIAS V = 0V, V = 0V ● 30 55 mV SENSE BIAS V = V + – V – = –128mV, V = 0V 10 mV SENSE S S BIAS Unipolar Output V = 2mV, V = 0V 32 50 mV SENSE BIAS Saturation Voltage V = 4mV, V = 0V 38 55 mV SENSE BIAS V = 5mV, V = 0V 43 60 mV SENSE BIAS V = 6mV, V = 0V 49 65 mV SENSE BIAS V = 2mV, V = 0V ● 32 60 mV SENSE BIAS V = 4mV, V = 0V ● 38 65 mV SENSE BIAS V = 5mV, V = 0V ● 43 70 mV SENSE BIAS V = 6mV, V = 0V ● 49 75 mV SENSE BIAS V Maximum Output Voltage V + – 0.75 V OMAX S RG1A, RG2A Input Gain-Setting Resistor Pin 1 to Pin 2, Pin 7 to Pin 8 1.25 kΩ ROUT Output Resistor Pin 5 to Pin 6 20 kΩ Note 1: Stresses beyond those listed under Absolute Maximum Ratings guaranteed functional over the operating temperature range of –40(cid:176)C to may cause permanent damage to the device. Exposure to any Absolute 125(cid:176)C. Maximum Rating condition for extended periods may affect device Note 4: The LT1787C is guaranteed to meet specified performance from reliability and lifetime. 0(cid:176)C to 70(cid:176)C. The LT1787C is designed, characterized and expected to Note 2: ESD (Electrostatic Discharge) sensitive devices. Extensive use of meet specified performance from –40(cid:176)C to 85(cid:176)C but is not tested or QA ESD protection devices are used internal to the LT1787/LT1787HV, sampled at these temperatures. The LT1787I is guaranteed to meet however, high electrostatic discharge can damage or degrade the device. specified performance from –40(cid:176)C to 85(cid:176)C. The LT1787H is guaranteed to Use proper ESD handling precautions. meet specified performance from –40(cid:176)C to 125(cid:176)C. Note 3: The LT1787C/LT1787I are guaranteed functional over the Note 5: Testing done at V = 1.25V, V = 0V unless otherwise BIAS EE operating temperature range of –40(cid:176)C to 85(cid:176)C. The LT1787H is specified. Note 6: This parameter is not 100% tested. TYPICAL PERFORWMANUCE CHARACTERISTICS Input Offset Voltage vs No Load Output Voltage No Load Output Current vs Supply Voltage vs Supply Voltage Supply Voltage 50 400 10 40 VS+ = VS– VS+ = VS– 8 TA = –40(cid:176)C VBIAS = 0V 300 VBIAS = 0V PUT OFFSET VOLTAGE (V)(cid:181)––32112000000 VEE = –1.25V TTAA = = 2855(cid:176)(cid:176)CC OUTPUT VOLTAGE (V)(cid:181)––2112000000000 VEE = –1.25V TA T=A 2 =5 (cid:176)8C5(cid:176)C OUTPUT CURRENT (nA) ––642024 TTAA == 2855(cid:176)(cid:176)CC IN––3400 TA = –40(cid:176)C –300 TA = –40(cid:176)C ––68 VVVBESEI+A ==S 0V=V S1–V –50 –400 –10 0 10 20 30 40 50 60 0 10 20 30 40 50 60 0 10 20 30 40 50 60 TOTAL SUPPLY VOLTAGE (V) TOTAL SUPPLY VOLTAGE (V) TOTAL SUPPLY VOLTAGE (V) 1787 G01 1787 G02 1787 G03 1787fc 6

LT1787/LT1787HV TYPICAL PERFORWMANUCE CHARACTERISTICS Input Offset Voltage vs Input Offset Voltage vs Output Voltage vs Sense Voltage Negative Supply Voltage Temperature (Bidirectional Mode) 30 50 VS+ = VS– = 2.5V 40 VS+ = VS– 2.5 VS = 5.5V TO 60V 20 VBIAS = 1V TA = 85(cid:176)C VBIAS = 0V 2.0 VBIAS = 2.5V V)(cid:181) V)(cid:181) 30 VEE = –1.25V 1.5 VEE = 0V AGE ( 10 AGE ( 20 E (V) 1.0 LT LT 10 AG 0.5 O O T FSET V 0 TA = 25(cid:176)C FSET V –100 UT VOLV–B0IA.5S NPUT OF –10 TA = –40(cid:176)C NPUT OF ––2300 OUTP ––11..05 I –20 I –2.0 –40 –2.5 –30 –50 0 –5 –10 –15 –20 –25 –30 –40 –20 0 20 40 60 80 –250 –150 –50 50 150 250 NEGATIVE SUPPLY VOLTAGE (V) TEMPERATURE ((cid:176)C) 85 SENSE VOLTAGE (VS+ – VS–) (mV) 1787 G04 1787 G05 1787 G06 Output Voltage vs Sense Voltage (Unidirectional Mode) Gain vs Temperature Gain vs Frequency 1.4 8.195 30 VS = 2.5V TO 60V VS = (2.5V + |VSENSE|)TO 60V VSENSE = 10mV 1.2 TA = –40(cid:176)C TO 85(cid:176)C 8.185 20 VBIAS = VEE TAGE (V) 10..08 V/V)8.175 VS+ > VS– dB) 100 OL N (8.165 N (–10 OUPUT V 00..64 GAI8.155 VS+ < VS– GAI–20 –30 0.2 8.145 –40 0 8.135 –50 0 30 60 90 120 150 –40 –20 0 20 40 60 80 0.1k 1k 10k 100k 1M 10M 100M SENSE VOLTAGE (VS+ – VS–) (mV) TEMPERATURE ((cid:176)C) 85 FREQUENCY (Hz) 1787 G07 1787 G08 1787 G09 Negative Input Sense Current vs Positive Input Sense Current vs Supply Current vs Supply Voltage Sense Voltage Sense Voltage 75 120 60 70 TA = 85(cid:176)C NT (A) (cid:181)111000 VS = (2.5V + |VSENSE|) TO 60V NT (A) (cid:181) 50 VS = (2.5V + |VSENSE|) TO 60V RRENT (A)(cid:181) 6650 TA = 25(cid:176)C NSE CURRE 9800 NSE CURRE 4300 TA = 85(cid:176)C SUPPLY CU 554505 VS+ = VS– TA = –40(cid:176)C NEGATIVE INPUT SE 76540000 TTTAAA === 28–554(cid:176)(cid:176)0CC(cid:176)C POSITIVE INPUT SE 2100 TA = 25(cid:176)C TA = –40(cid:176)C 40 30 0 0 10 20 30 40 50 60 –128–96 –64 –32 0 32 64 96 128 –128–96 –64 –32 0 32 64 96 128 TOTAL SUPPLY VOLTAGE (V) SENSE VOLTAGE (VS+ – VS–) (mV) SENSE VOLTAGE (VS+ – VS–) (mV) 1787 G10 1787 G11 1787 G17 1787fc 7

LT1787/LT1787HV TYPICAL PERFORWMANUCE CHARACTERISTICS Step Response at Step Response at Step Response at V = 0V to 10mV V = 0V to 128mV V = 0V to 128mV SENSE SENSE SENSE 10mV 100mV 100mV 0V 0V 0V 80mV 1V 1V 500mV 500mV 0V 0V 0V COUT = 0pF 1787 G12 COUT = 0pF 1787 G18 COUT = 1000pF 1787 G13 Step Response at Step Response at Step Response at V = 0V to –128mV V = 0V to –128mV V = –128mV to 128mV SENSE SENSE SENSE 0V 0V 100mV 0V –100mV –100mV –100mV 0V 0V 1V –500mV –500mV 0V –1V –1V –1V COUT = 0 1787 G19 COUT = 1000pF 1787 G14 COUT = 0 1787 G20 Step Response at V Error vs Supply Ripple OUT VSENSE = 128mV to –128mV Voltage (VSENSE = –128mV) Output Voltage vs Sense Voltage 1000 16 100mV 900 14 VS– = 18V –100mV E (mV)870000 V) 1120 VVBEEIA =S –=1 08VV AG E ( 8 1V LT600 AG 6 O T V L –01VV PPLE 540000 0.5% 5% UT VO 42 PLY RI300 1%2% OUTP –02 UP200 VOUT ERROR COUT = 2200pF 1787 G15 S LESS THAN 0.1% –4 100 –6 0 –8 100 1k 10k 100k 1M –0.8 –0.4 0 0.4 0.8 1.2 1.6 2.0 FREQUENCY (Hz) SENSE VOLTAGE (VS+ – VS–) (V) 1787 G16 1787 G21 1787fc 8

LT1787/LT1787HV PIUN FUUNCTIOUNS FIL–, FIL+ (Pins 1, 8): Negative and Positive Filter Termi- where: nals. Differential mode noise can be filtered by connecting V > V for V + > V – a capacitor across FIL– and FIL+. Pole frequency VOUT < VBIAS for VS+ < VS– OUT BIAS S S f = 1/(2πRC), R = 1.25kΩ. –3dB V is the no load output voltage at V = 0V. V – (Pin 2): Negative Input Sense Terminal. Negative OUT(O) SENSE S V (Pin 6): Output Bias Pin. For single supply, bidirec- sense voltage will result in an output sinking current BIAS proportional to the sense current. V – is connected to an tional current sensing operation, VBIAS is connected to an S external bias voltage, so that at V = 0V, V = internal gain-setting resistor R and supplies bias cur- SENSE OUT G1A V + V . For dual supply, bidirectional current rent to the internal amplifier. OUT(O) BIAS sensing operation, V is connected to ground. Thus, BIAS DNC (Pin 3): Do Not Connect. Connected internally. Do not V = V at V = 0V. OUT OUT(O) SENSE connect external circuitry to this pin. V + (Pin 7): Positive Input Sense Terminal. Positive sense S V (Pin 4): Negative Supply or Ground for Single Supply EE voltage will result in an output sourcing current propor- Operation. tional to the sense current. V + is connected to an internal S VOUT (Pin 5): Voltage Output or Current Output propor- gain-setting resistor RG2A. Connecting a supply to VS+ and tional to the magnitude of the sense current flowing a load to VS– will allow the LT1787 to measure its own through R . For bidirectional current sensing opera- supply current. SENSE tion, V = A • V + V + V , OUT V SENSE OUT(O) BIAS BLOCK DIAGRAWM RSENSE ISENSE VS– VS+ RG1A RG2A 1.25k 1.25k FIL– FIL+ RG1B RG2B 1.25k 1.25k – + A1 IOUT VBIAS Q1 Q2 ROUT 20k VOUT VEE CURRENT MIRROR 1787 F 01 Figure 1. LT1787 Functional Diagram 1787fc 9

LT1787/LT1787HV APPLICATIOUNS INUFORWMATIOUN The LT1787 high side current sense amplifier (Figure 1) Kelvin connection of the LT1787’s V + and V – inputs to S S provides accurate bidirectional monitoring of current the sense resistor should be used in all but the lowest through a user-selected sense resistor. The sense voltage power applications. Solder connections and PC board is amplified by a fixed gain of 8 and level shifted from the interconnect resistance (approximately 0.5mΩ per square) positive power supply to the ground referenced outputs. can be a large error in high current systems. A 5-Amp The output signal may be used in a variety of ways to application might choose a 20mΩ sense resistor to give a interface with subsequent signal processing circuitry. 100mV full-scale input to the LT1787. Input offset voltage Input and output filtering are easily implemented to elimi- will limit resolution to 2mA. Neglecting contact resistance nate aliasing errors. at solder joints, even one square of PC board copper at each resistor end will cause an error of 5%. This error will Theory of Operation grow proportionately higher as monitored current levels Inputs V + and V – apply the sense voltage to matched rise to tens or hundreds of amperes. S S resistors R and R . The opposite ends of resistors R G1 G2 G1 Input Noise Filtering and R are forced to be at equal potentials by the voltage G2 gain of amplifier A1. The currents through R and R are The LT1787 provides input signal filtering pins FIL+ and G1 G2 forced to flow through transistors Q1 and Q2 and are FIL– that are internally connected to the midpoint taps of summed at node V by the 1:1 current mirror. The net resistors R and R . These pins may be used to filter the OUT G1 G2 current from R and R flowing through resistor R input signal entering the LT1787’s internal amplifier, and G1 G2 OUT gives a voltage gain of eight. Positive sense voltages result should be used when fast current ripple or transients may in V being positive with respect to pin V . flow through the sense resistor. High frequency signals OUT BIAS above the 300kHz bandwidth of the LT1787’s internal Pins V , V and V may be connected in a variety of EE BIAS OUT amplifier will cause errors. A capacitor connected between ways to interface with subsequent circuitry. Split supply FIL+ and FIL– creates a single pole low pass filter with and single supply output configurations are shown in the corner frequency: following sections. Supply current for amplifier A1 is drawn from the V – pin. f–3dB = 1/(2πRC) S The user may choose to include this current in the moni- where R = 1.25k. A 0.01(cid:181)F capacitor creates a pole at tored current through R by careful choice of connec- 12.7kHz, a good choice for many applications. SENSE tion polarity. Common mode filtering from the FIL+ and FIL– pins should not be attempted, as mismatch in the capacitors from FIL+ Selection of External Current Sense Resistor and FIL– will create AC common mode errors. Common External RSENSE resistor selection is a delicate trade-off mode filtering must be done at the power supply output. between power dissipation in the resistor and current measurement accuracy. The LT1787 makes this decision Output Signal Range less difficult than with competitors’ products. The maxi- The LT1787’s output signal is developed by summing the mum sense voltage may be as large as –500mV to get net currents through R and R into output resistor G1 G2 maximum resolution, however, high current applications R . The pins V and V may be connected in OUT OUT BIAS will not want to suffer this much power dissipation in the numerous configurations to interface with following cir- sense resistor. The LT1787’s input offset voltage of 40(cid:181)V cuitry in either single supply or split supply applications. gives high resolution for low sense voltages. This wide Care must be used in connecting the output pins to operating dynamic range gives the user wide latitude in preserve signal accuracy. Limitations on the signal swing tailoring the range and resolution of his supply monitoring at V are imposed by the negative supply, V , and the OUT EE function. input voltage V +. In the negative direction, internal circuit S saturation with loss of accuracy occurs for V < 70mV OUT 1787fc 10

LT1787/LT1787HV APPLICATIOUNS INUFORWMATIOUN with absolute minimum swing at 30mV above VEE. VOUT 1.5 may swing positive to within 0.75V of VS+ or a maximum VTAS == –3.430V(cid:176) CT OT O6 08V5(cid:176)C 1.0 of 35V, a limit set by internal junction breakdown. Within these contraints, an amplified, level shifted representation E (V) 0.5 G of the R voltage is developed across R . A SENSE OUT T L O 0 V T Split Supply Bipolar Output Swing PU UT–0.5 O Figure 2 shows the LT1787 used with split power supplies. –1.0 The V pin is connected to ground, and the output BIAS signal appears at the V pin. Bidirectional input currents OUT –1.5 –128–96 –64 –32 0 32 64 96 128 can be monitored with the output swinging positive for SENSE VOLTAGE (VS+ – VS–) (mV) current flow from V + and V –. Input currents in the S S 1787 F03 opposite direction cause V to swing below ground. Figure 3. Split Supply Output Voltage OUT Figure 2 shows an optional output capacitor connected from V to ground. This capacitor may be used to filter OUT the output signal before it is processed by other TO RSENSE CHARGER/ 3.3V circuitry.Figure 3 shows the voltage transfer function of LOAD C1 TO the LT1787 used in this configuration. 1 FIL– FIL+ 8 1(cid:181)F 60V 3.3V LT1787HV 2 VS– VS+ 7 20k Single Supply with Shifted V 5% BIAS 3 VBIAS 6 DNC Figure 4 shows the LT1787 used in a single supply mode 4 ROUT 5 1C(cid:181)2F LT1634-1.25 with the V pin shifted positive using an external VEE BIAS VOUT LT1634 voltage reference. The V output signal can C3* OUT 1000pF swing above and below V to allow monitoring of BIAS *OPTIONAL OUTPUT 1787 F04 positive or negative currents through the sense resistor, as shown in Figure 5. The choice of reference voltage is not Figure 4. Charge/Discharge Current Monitor on critical except for the precaution that adequate headroom Single Supply with V = 1.25V BIAS must be provided for V to swing without saturating the OUT internal circuitry. The component values shown in Figure 4 allow operation with V supplies as low as 3.1V. S V) 1.5 E ( VS = 3.3V TO 60V AG TA = –40(cid:176)C TO 85(cid:176)C LT 1.0 TO RSENSE VO CHARLGOEARD/ C1 15V T BIAS 0.5 1 FIL– FIL+ 8 1(cid:181)F UTPU 0 LT1787 O 2 VS– VS+ 7 E – G –0.5 3 DNC VBIAS 6 OLTA ROUT UT V –1.0 4 5 P VEE OUTPUT UT VOUT O –1.5 C2 C3* –128–96 –64 –32 0 32 64 96 128 –5V 1(cid:181)F 1000pF SENSE VOLTAGE (VS+ – VS–) (mV) 1787 F02 1787 F05 *OPTIONAL Figure 5. Single Supply Output Voltage Figure 2. Split Supply Operation with V = 1.25V BIAS 1787fc 11

LT1787/LT1787HV APPLICATIOUNS INUFORWMATIOUN Operation with A/D Converter RSENSE Figure 6 shows the LT1787 operating with the LTC1286 5V C1 5V A/D converter. This low cost circuit is capable of 12-bit 1 FIL– FIL+ 8 1(cid:181)F LT1787 resolution of unipolar currents. The –IN pin of the A/D 2 VS– VS+ 7 R1 20k converter is biased at 1V by the resistor divider R1 and R2. 3 VBIAS 6 IOUT 5% DNC Tamhisp lvifoieltda gsee ninscer evaoslteasg aes a spepnesaer cinugrr benettw inecerne atshees A, w/Dit hc othne- 4 VEE ROUT 5 +IN VCC CS VOUT LTC1286 CLK TO (cid:181)P verters –IN and +IN terminals. The front page of the data R2 –INVREF GND DOUT sheet shows a similar circuit which uses a voltage refer- 5k 1787 F06 5% ence for improved accuracy and signal range. The LTC1286 converter uses sequential sampling of its –IN and +IN Figure 6. Unidirectional Output into A/D inputs. Accuracy is degraded if the inputs move between with Fixed Supply at V + sampling intervals. A filter capacitor from FIL+ to FIL– as S well as a filter capacitor from V to V may be BIAS OUT necessary if the sensed current changes more than 1LSB ISENSE TO RSENSE within a conversion cycle. CHARGER/ LOAD C1 Buffered Output Operation 1 FIL– FIL+ 8 1(cid:181)F 2.5V + VSENSE(MAX) LT1787 2 VS– VS+ 7 Figure 7 shows the LT1787’s outputs buffered by an 2.5V operational amplifier configured as an I/V converter. This 3 DNC VBIAS 6 C3 configuration is ideal for monitoring very low voltage 4 ROUT 5 1000pF supplies. The LT1787’s V pin is held equal to the VEE OUT VOUT – reference voltage appearing at the op amp’s noninverting A1 VOUT A input. This allows monitoring VS supplies as low as 2.5V. 2.5V + LT1495 1M The op amp’s output may swing from ground to its positive 5% LT1389-1.25 supply voltage. The low impedance output of the op amp 1787 F07 may drive following circuitry more effectively than the high output impedance of the LT1787. The I/V converter configu- Figure 7. Single Supply 2.5V Bidirectional Operation ration also works well with split supply voltages. with External Voltage Reference and I/V Converter Single Supply Unidirectional Operation TO RSENSE Figure 8 shows the simplest connection in which the LOAD C 2.5V TO LT1787 may be used. The VBIAS pin is connected to 0.1(cid:181)F 60V ground, and the V pin swings positive with increasing OUT sense current. The LT1787’s outputs can swing as low as 1 FIL– FIL+ 8 30mV as shown in Figure 9. Accuracy is sacrificed at small LT1787HV 2 VS– VS+ 7 output levels, but this is not a limitation in protection circuit applications or where sensed currents do not vary 3 DNC VBIAS 6 greatly. Increased low level accuracy can be obtained by ROUT 4 5 level shifting V above ground. The level shifting may be VEE VOUT BIAS VOUT done with resistor dividers, voltage references or a simple 1787 F08 diode. Accuracy is ensured if the output signal is sensed Figure 8. Unidirectional Current Sensing Mode differentially between V and V . BIAS OUT 1787fc 12

LT1787/LT1787HV APPLICATIOUNS INUFORWMATIOUN 0.30 resistor. When an external resistor is used, leave the VBIAS pin floating or connected to the V pin. This will remove OUT 0.25 the internal R from the circuit. OUT V) E ( 0.20 The voltage gain will be gm • R where gm is the G OUT A LT LT1787’s transconductance, 400(cid:181)A/V typical. A nominal O 0.15 V T gain of 40 may be obtained with an external 100k resistor U P OUT 0.10 used in place of the internal 20k ROUT: 0.05 AV = gm • ROUT = 400(cid:181)A/V • 100k = 40 IDEAL The transconductance gm is set by on-chip resistors on 0 0 0.005 0.010 0.015 0.020 0.025 0.030 the LT1787. These resistors match well but have loose VS+ – VS– (V) absolute tolerance. This will normally require that the 1787 F09 external gain setting resistor be trimmed for initial accu- Figure 9. Expanded Scale of Unidirectional Output racy. After trimming, the temperature stability of the gm and therefore gain will be –200ppm/(cid:176)C. Adjusting Gain Setting The only limitations placed upon the resistor choice is care The LT1787 may be used in all operating modes with an must be taken not to saturate the internal circuitry by external resistor used in place of the internal 20k R violating the V specification of V + –0.75V. OUT OMAX S 1787fc 13

LT1787/LT1787HV PACKAGE DESCRIPTIOUN MS8 Package 8-Lead Plastic MSOP (LTC DWG # 05-08-1660) 0.889 – 0.127 (.035 – .005) 5.23 3.20 – 3.45 (.206) (.126 – .136) MIN 3.00 – 0.102 0.42 – 0.038 0.65 (.118 – .004) 0.52 (.0165 – .0015) (.0256) (NOTE 3) 8 7 6 5 (.0205) TYP BSC REF RECOMMENDED SOLDER PAD LAYOUT 3.00 – 0.102 4.90 – 0.152 DETAIL “A” (.118 – .004) 0.254 (.193 – .006) (NOTE 4) (.010) 0(cid:176) – 6(cid:176) TYP GAUGE PLANE 1 2 3 4 0.53 – 0.152 (.021 – .006) 1.10 0.86 (.043) (.034) DETAIL “A” MAX REF 0.18 (.007) SEATING PLANE 0.22 – 0.38 0.127 – 0.076 (.009 – .015) (.005 – .003) TYP 0.65 MSOP (MS8) 0204 (.0256) NOTE: BSC 1. DIMENSIONS IN MILLIMETER/(INCH) 2. DRAWING NOT TO SCALE 3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX 1787fc 14

LT1787/LT1787HV PACKAGE DESCRIPTIOUN S8 Package 8-Lead Plastic Small Outline (Narrow 0.150) (LTC DWG # 05-08-1610) .189 – .197 .045 –.005 (4.801 – 5.004) .050 BSC NOTE 3 8 7 6 5 .245 MIN .160 –.005 .150 – .157 .228 – .244 (3.810 – 3.988) (5.791 – 6.197) NOTE 3 .030 –.005 TYP 1 2 3 4 RECOMMENDED SOLDER PAD LAYOUT .010 – .020 (cid:215) 45(cid:176)(cid:31) .053 – .069 (0.254 – 0.508) (1.346 – 1.752) .004 – .010 .008 – .010 (0.203 – 0.254) 0(cid:176)– 8(cid:176) TYP (0.101 – 0.254) .016 – .050 .014 – .019 .050 (0.406 – 1.270) (0.355 – 0.483) (1.270) NOTE: INCHES TYP BSC 1. DIMENSIONS IN (MILLIMETERS) 2. DRAWING NOT TO SCALE 3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm) SO8 0303 1787fc Information furnished by Linear Technology Corporation is believed to be accurate and reliable. 15 However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.

LT1787/LT1787HV TYPICAL APPLICATIONU Split or Single Supply Operation, Bidirectional Output into A/D 1Ω 1% IS = –125mA VCC 5V VSRCE 1 FIL– FIL+ 8 ≈4.75V LT1787 2 VS– VS+ 7 10(cid:181)F 16V 3 VBIAS 6 1 DNC 7 20k CONV –V5EVE 4 VEE VOUT 5 VOUOT P(T–I1OVN)AL SINGLE 23 AVINREFLTC1404DOCULKT 56 CCILROCCUKITINRGY SUPPLY OPERATION: 10(cid:181)F GND DISCONNECT VBIAS 16V 4 8 FROM GROUND AND CONNECT IT TO VREF. 10(cid:181)F DOUT REPLACE –5V SUPPLY 16V OUTPUT CWOIDTEH FGORRO ZUENRDO. –V5EVE 1787 TA02 CURRENT WILL BE ~2430 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC1043 Dual Precision Instrumentation Switched Capacitor Building Block 120dB CMRR, 3V to 18V Operation LT1490/LT1491 Dual and Quad Micropower Rail-to-Rail Input and Output Op Amps 50(cid:181)A Amplifier, 2.7V to 40V Operation, Over-The-TopTM Inputs LT1620/LT1621 Rail-to-Rail Current Sense Amplifiers Accurate Output Current Programming, Battery Charging to 32V Over-The-Top is a trademark of Linear Technology Corporation. 1787fc 16 Linear Technology Corporation LT 0606 REV C (cid:149) PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com ' LINEAR TECHNOLOGY CORPORATION 1999