LTC1440/LTC1441/LTC1442 Ultralow Power Single/Dual Comparator with Reference FEATURES DESCRIPTIOU ■ Ultralow Quiescent Current: 2.1µA Typ (LTC1440) The LTC®1440/LTC1441/LTC1442 are ultralow power ■ Reference Output Drives 0.01µF Capacitor single and dual comparators with built-in references. The ■ Adjustable Hysteresis (LTC1440/LTC1442) comparators feature less than 3.7µA supply current over ■ Wide Supply Range: temperature (LTC1440), a 1.182V ±1% reference, pro- Single: 2V to 11V grammable hysteresis (LTC1440/LTC1442) and TTL/CMOS Dual: ±1V to ±5.5V outputs that sink and source current. The reference output ■ Input Voltage Range Includes the Negative Supply can drive a bypass capacitor of up to 0.01µF without ■ TTL/CMOS Compatible Outputs oscillation. ■ 12µs Propagation Delay with 10mV Overdrive The comparators operate from a single 2V to 11V supply ■ No Crowbar Current or a dual ±1V to ±5.5V supply (LTC1440). Comparator ■ 40mA Continuous Source Current hysteresis is easily programmed by using two resistors ■ Pin Compatible Upgrades for MAX921/922/923 and the HYST pin (LTC1440/LTC1442). Each comparator’s ■ 3mm x 3mm x 0.75mm DFN Package (LTC1440) input operates from the negative supply to within 1.3V of the positive supply. The comparator output stage can APPLICATIOU S continuously source up to 40mA. By eliminating the cross-conducting current that normally happens when the ■ Battery-Powered System Monitoring comparator changes logic states, the power supply glitches ■ Threshold Detectors are eliminated. ■ Window Comparators ■ Oscillator Circuits The LTC1440 is available in 8-pin PDIP, SO, MSOP and DFN packages. The LTC1441/LTC1442 are available in , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. 8-pin PDIP and SO packages. TYPICAL APPLICATIOU Micropower 2.9V V Threshold Detector CC LTC1440 Supply Current vs Temperature 3.3V 5.0 V+ = 5V R1 7 4.5 V– = GND = 0V 1.65M V+ 1% 3 IN+ + T (A)µ 4.0 R2 8 OUT REN 3.5 11.%13M 4 IN– – Y CUR 3.0 L P P 5 HYST U 2.5 S 2.0 LTC1440 6 REF 1.5 –40 –20 0 20 40 60 80 100 V– GND TEMPERATURE (°C) 2 1 1440/1/2 TA02 1440 TA01 144012fd 1

LTC1440/LTC1441/LTC1442 ABSOLUTE WMAXIWMUWM RATINUGS (Note 1) Voltage OUT Short-Circuit Duration (V+ ≤ 5.5V).......Continuous V+ to V–, V+ to GND, GND to V–...........12V to –0.3V Power Dissipation..............................................500mW IN+, IN–, HYST.................(V+ + 0.3V) to (V––0.3V) Operating Temperature Range REF...................................(V+ + 0.3V) to (V––0.3V) LTC144XC ...............................................0°C to 70°C OUT (LTC1440)..............(V+ + 0.3V) to (GND–0.3V) LTC144XI ........................................... –40°C to 85°C OUT (LTC1441/LTC1442)...(V+ + 0.3V) to (V––0.3V) Storage Temperature Range................. –65°C to 150°C Current Storage Temperature Range IN+, IN–, HYST................................................. 20mA (DD Package) ................................... –65°C to 125°C REF................................................................... 20mA Junction Temperature...........................................150°C OUT.................................................................. 50mA Junction Temperature (DD Package)....................125°C Lead Temperature (Soldering, 10 sec)..................300°C PACKAGE/ORDER IUNFORWMATIOUN TOP VIEW TOP VIEW GND 1 8 OUT GND 1 8 OUT TOP VIEW INV–+ 32 67 VRE+F V– 2 7 V+ GNVD– 12 87OVU+T IN– 4 5 HYST IN+ 3 6 REF IINN+– 34 65RHEYFST IN– 4 5 HYST MS8 PACKAGE DD PACKAGE N8 PACKAGE S8 PACKAGE 8-LEAD PLASTIC MSOP 8-LEAD (3mm × 3mm) PLASTIC DFN 8-LEAD PDIP 8-LEAD PLASTIC SO TJMAX = 150°C, θJA = 250°C/W TJMAX = 125°C, θJA = 160°C/W (DD) TJMAX = 150°C, θJA = 130°C/W (N8) UNDERSIDE METAL CONNECTED TO V– TJMAX = 150°C, θJA = 175°C/W (S8) (PCB CONNECTION OPTIONAL) ORDER PART DD8 PART ORDER PART S8 PART ORDER PART MS8 PART NUMBER MARKING* NUMBER MARKING NUMBER MARKING* LTC1440CDD LBTH LTC1440CN8 1440 LTC1440CMS8 LTBX LTC1440IDD LTC1440CS8 1440 LTC1440IMS8 LTC1440IN8 1440I LTC1440IS8 1440I ORDER PART ORDER PART TOP VIEW NUMBER TOP VIEW NUMBER OUT A 1 8 OUT B LTC1441CN8 OUT A 1 8 OUT B LTC1442CN8 V– 2 7 V+ LTC1441CS8 V– 2 7 V+ LTC1442CS8 IN A+ 3 6 IN B+ LTC1441IN8 IN A+ 3 6 REF LTC1442IN8 IN A– 4 5 IN B– LTC1441IS8 IN B– 4 5 HYST LTC1442IS8 S8 PART S8 PART N8 PACKAGE S8 PACKAGE N8 PACKAGE S8 PACKAGE 8-LEAD PDIP 8-LEAD PLASTIC SO MARKING 8-LEAD PDIP 8-LEAD PLASTIC SO MARKING TJMAX = 150°C, θJA = 130°C/W (N8) 1441 TJMAX = 150°C, θJA = 130°C/W (N8) 1442 TJMAX = 150°C, θJA = 175°C/W (S8) TJMAX = 150°C, θJA = 175°C/W (S8) 1441I 1442I 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. * The temperature grade is identified by a label on the shipping container. 144012fd 2

LTC1440/LTC1441/LTC1442 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T = 25°C. V+ = 5V and V– = GND = 0V unless otherwise noted. A SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Power Supply V+ Supply Voltage Range ● 2.0 11.0 V ICC Supply Current IN+ = IN– + 80mV LTC1440 0°C ≤ TA ≤ 70°C ● 2.1 4.0 µA HYST = REF (LTC1440/LTC1442) –40°C ≤ TA ≤ 85°C ● 4.4 µA LTC1441 ● 3.5 5.7 µA LTC1442 ● 3.5 5.7 µA Comparator VOS Comparator Input Offset Voltage VCM = 2.5V ● ±3 ±10 mV IIN Input Leakage Current (IN+, IN–) VIN+ = VIN– = 2.5V ● ±0.01 ±1.0 nA Input Leakage Current (HYST) ● ±0.02 ±1.0 nA V Comparator Input Common ● V– V+ – 1.3V V CM Mode Range CMRR Common Mode Rejection Ratio V– to V+ – 1.3V 0.1 1 mV/V PSRR Power Supply Rejection Ratio V+ = 2V to 11V (LTC1441) 0.1 1 mV/V V+ = 2.5V to 11V (LTC1440/LTC1442) 0.1 1 mV/V NOISE Voltage Noise 100Hz to 100kHz 100 µVRMS V Hysteresis Input Voltage Range LTC1440/LTC1442 ● REF–50mV REF V HYST tPD Propagation Delay COUT = 100pF Overdrive = 10mV 15 µs Overdrive = 100mV 8 µs V Output High Voltage I = –13mA ● V+ – 0.4V V OH O V Output Low Voltage I = 1.8mA LTC1440 ● GND + 0.4V V OL O LTC1441/LTC1442 ● V– + 0.4V V Reference V Reference Voltage No Load LTC1440/LTC1442 REF 0°C ≤ TA ≤ 70°C ● 1.170 1.194 V –40°C ≤ TA ≤ 85°C ● 1.164 1.200 V LTC1440 (MSOP, DFN) ● 1.164 1.200 V ISOURCE Reference Output Source Current ∆VREF ≤ 1mV (LTC1442) ● 100 µA ISINK Reference Output Sink Current ∆VREF ≤ 2.5mV (LTC1442) 10 20 µA ∆VREF Reference Source Current 0 ≤ ISOURCE ≤ 2mA (LTC1440) ● 0.8 5 mV Reference Sink Current 0 ≤ ISINK ≤ 10µA (LTC1440) 0.5 1.5 mV ● 5 mV NOISE Voltage Noise 100Hz to 100kHz 100 µVRMS 144012fd 3

LTC1440/LTC1441/LTC1442 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T = 25°C. V+ = 3V and V– = GND = 0V unless otherwise noted. A SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Power Supply V+ Supply Voltage Range ● 2 11 V ICC Supply Current IN+ = IN– + 80mV LTC14400°C ≤ TA ≤ 70°C ● 2 3.9 µA HYST = REF (LTC1440/LTC1442) –40°C ≤ TA ≤ 85°C ● 4.3 µA LTC1441 ● 3.5 5.7 µA LTC1442 ● 3.5 5.7 µA Comparator VOS Comparator Input Offset Voltage VCM = 1.5V ● ±3 ±10 mV IIN Input Leakage Current (IN+, IN–) VIN+ = VIN– = 1.5V ● ±0.01 ±1 nA Input Leakage Current (HYST) ● ±0.02 ±1 nA V Comparator Input Common ● V– V+ – 1.3V V CM Mode Range CMRR Common Mode Rejection Ratio V– to V+ – 1.3V 0.1 1 mV/V PSRR Power Supply Rejection Ratio V+ = 2V to 11V (LTC1441) 0.1 1 mV/V V+ = 2.5V to 11V (LTC1440/LTC1442) 0.1 1 mV/V NOISE Voltage Noise 100Hz to 100kHz 100 µVRMS V Hysteresis Input Voltage Range LTC1440/LTC1442 ● REF–50mV REF V HYST tPD Propagation Delay COUT = 100pF Overdrive = 10mV 14 µs Overdrive = 100mV 5 µs V Output High Voltage I = –8mA ● V+ – 0.4V V OH O Comparator V Output Low Voltage I = 0.8mA LTC1440 ● GND + 0.4V V OL O LTC1441/LTC1442 ● V– + 0.4V V Reference V Reference Voltage No Load LTC1440/LTC1442 REF 0°C ≤ TA ≤ 70°C ● 1.170 1.182 1.194 V –40°C ≤ TA ≤ 85°C ● 1.164 1.200 V LTC1440 (MSOP, DFN) ● 1.164 1.200 V ISOURCE Reference Output Source Current ∆VREF ≤ 1mV (LTC1442) ● 60 120 µA ISINK Reference Output Sink Current ∆VREF ≤ 2.5mV (LTC1442) 10 20 µA ∆VREF Reference Source Current 0 ≤ ISOURCE ≤ 1mA (LTC1440) ● 0.8 5.5 mV Reference Sink Current 0 ≤ ISINK ≤ 10µA (LTC1440) 0.5 1.5 mV ● 5 mV NOISE Voltage Noise 100Hz to 100kHz 100 µVRMS Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. 144012fd 4

LTC1440/LTC1441/LTC1442 TYPICAL PERFORW AU CE CHARACTERISTICS Comparator Response Time vs Comparator Response Time vs Input Overdrive Input Overdrive 5 5 OUTPUT VOLTAGE (V) 1234 TA = 25°C50m1V00mV 1200mmVV OUTPUT VOLTAGE (V) 1234 TA = 251°0C0mV 50mV 20mV10mV 0 0 V) V) m m E ( E ( G G TA 0 TA100 L L O O V100 V 0 T T U U P P N N I –1 0 2 4 6 8 10 I –1 0 2 4 6 8 10 12 14 16 18 RESPONSE TIME (µs) RESPONSE TIME (µs) 1440/1/2 G01 1440/1/2 G02 Comparator Short-Circuit Sink Comparator Short-Circuit Source Current vs Supply Voltage Current vs Supply Voltage 200 160 180 TA = 25°C 140 160 RENT (mA) 111420000 OUT CONNECTED TO V+ RRENT (mA) 11208000 OUT CVO–N N= EGCNTDE D= T0OV R U U C SINK C 8600 OURCE 60 S 40 40 20 20 0 0 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V) 1440/1/2 G03 1440/1/2 G04 144012fd 5

LTC1440/LTC1441/LTC1442 TYPICAL PERFORW AU CE CHARACTERISTICS Comparator Response Time vs Load Capacitance with 100mV Comparator Response Time at Input Overdrive Low Supply Voltage 12 10000 10 tPHL 1000 RESPONSE TIME (s)µ 86 tPLH RESPONSE TIME (s)µ 100 20mV OVERDRIVE 10 4 100mV OVERDRIVE 2 1 0 20 40 60 80 100 1.0 1.1 1.2 1.3 1.4 1.5 1.6 LOAD CAPACITANCE (nF) SUPPLY VOLTAGE (V) 1440/1/2 G05 1440/1/2 G06 Comparator Output Voltage High vs Load Current 5 TA = 25°C H (V) 4 V+ = 5V G HI E G TA 3 L O T V V+ = 3V U P UT 2 O V+ = 2V 1 0 10 20 30 40 50 60 LOAD CURRENT (mA) 1440/1/2 G07 144012fd 6

LTC1440/LTC1441/LTC1442 TYPICAL PERFORW AU CE CHARACTERISTICS Comparator Output Voltage Low LTC1440/LTC1442 vs Load Current Hysteresis Control 2.5 V) 80 TA = 25°C m E ( 60 E LOW (V) 21..05 V+ = 2V V+ = 3V PUT VOLTAG 4200 OUTPUT HIGH TAG V+ = 5V E IN 0 L V T VO 1.0 GATI –20 OUTPUT LOW U E P N UT O- –40 O 0.5 E-T V TI –60 SI O 0 P –80 0 10 20 30 40 50 60 70 80 0 10 20 30 40 50 LOAD CURRENT (mA) VREF – VHYST (mV) 1440/1/2 G08 1440/1/2 G09 LTC1440 Supply Current vs Temperature 6 5 A) V+ = 5V µT ( V– = –5V N 4 E R R U C Y 3 L PP V+ = 3V SU V– = GND = 0V 2 V+ = 5V V– = GND = 0V 1 –60–40 –20 0 20 40 60 80 100120140 TEMPERATURE (°C) 1440/1/2 G10 144012fd 7

LTC1440/LTC1441/LTC1442 TYPICAL PERFORW AU CE CHARACTERISTICS Reference Output Voltage vs Reference Output Voltage vs Output Load Current Output Load Current (Sink) 1.190 1.200 VCC = 5V VCC = 2V GE (V)1.185 SOURCE GE (V)1.195 VCC = 5V OLTA1.180 OLTA1.190 UT V1.175 UT V OUTP1.170 OUTP1.185 SINK RENCE 1.165 RENCE 1.180 REFE1.160 REFE1.175 1.155 1.170 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 0 5 10 15 20 25 30 OUTPUT LOAD CURRENT (mA) OUTPUT LOAD CURRENT (µA) 1440/1/2 G11 1440/1/2 G12 Reference Voltage vs Temperature 1.186 1.184 V)1.182 E ( G A1.180 T L O V1.178 E C N E1.176 R E F RE1.174 1.172 1.170 –60–40 –20 0 20 40 60 80 100120140 TEMPERATURE (°C) 1440/1/2 G13 144012fd 8

LTC1440/LTC1441/LTC1442 PIUN FUUNCTIOUNS 1 LTC1440 OUT 8 1 OUT A LTC1441 OUT B 8 1 OUT A LTC1442 OUT B 8 GND 2 V– V+ 7 2 V– V+ 7 2 V– A B V+ 7 A B + + – – + + – – + 3 IN+ – REF 6 3 IN A+ IN B+ 6 3 IN A+ REF 6 4 IN– HYST 5 4 IN A– IN B– 5 4 IN B– V– HYST 5 1440/1/2 PD LTC1440 IN B– (Pin 5): Inverting Input of Comparator B. Input common mode range from V– to V+ –1.3V. Input current GND (Pin 1): Ground. Connect to V– for single supply typically 10pA at 25°C. operation. IN B+ (Pin 6): Noninverting Input of Comparator B. Input V– (Pin 2): Negative Supply. Connect to ground for single common mode range from V– to V+ –1.3V. Input current supply operation. Potential should be more negative than typically 10pA at 25°C. GND. V+ (Pin 7): Positive Supply. 2V to 11V. IN+ (Pin 3): Noninverting Comparator Input. Input com- mon mode range from V– to V+ –1.3V. Input current OUT B (Pin 8): Comparator B CMOS Output. Swings from typically 10pA at 25°C. V– to V+. Output can source up to 40mA and sink 5mA. IN– (Pin 4): Inverting Comparator Input. Input common LTC1442 mode range from V– to V+ –1.3V. Input current typically 10pA at 25°C. OUT A (Pin 1): Comparator A CMOS Output. Swings from V– to V+. Output can source up to 40mA and sink 5mA. HYST (Pin 5): Hysteresis Input. Connect to REF if not used. Input voltage range is from V to V – 50mV. V– (Pin 2): Negative Supply. REF REF REF (Pin 6): Reference Output. 1.182V with respect IN A+ (Pin 3): Noninverting Input of Comparator A. Input to V–. Can source up to 200µA and sink 15µA at 25°C. common mode range from V– to V+ –1.3V. Input current Drive 0.01µF bypass capacitor without oscillation. typically 10pA at 25°C. V+ (Pin 7): Positive Supply. 2V to 11V. IN B– (Pin 4): Inverting Input of Comparator B. Input common mode range from V– to V+ –1.3V. Input current OUT (Pin 8): Comparator CMOS Output. Swings from GND to V+. Output can source up to 40mA and sink 5mA. typically 10pA at 25°C. HYST (Pin 5): Hysteresis Input. Connect to REF if not LTC1441 used. Input voltage range is from V to V – 50mV. REF REF OUT A (Pin 1): Comparator A CMOS Output. Swings from REF (Pin 6): Reference Output. 1.182V with respect V– to V+. Output can source up to 40mA and sink 5mA. to V–. Can source up to 200µA and sink 15µA at 25°C. Drive 0.01µF bypass capacitor without oscillation. V– (Pin 2): Negative Supply. V+ (Pin 7): Positive Supply. 2V to 11V. IN A+ (Pin 3): Noninverting Input of Comparator A. Input common mode range from V– to V+ –1.3V. Input current OUT B (Pin 8): Comparator B CMOS Output. Swings from typically 10pA at 25°C. V– to V+. Output can source up to 40mA and sink 5mA. IN A– (Pin 4): Inverting Input of Comparator A. Input common mode range from V– to V+ –1.3V. Input current typically 10pA at 25°C. 144012fd 9

LTC1440/LTC1441/LTC1442 APPLICATIOUNS INUFORWMATIOUN LTC1440/LTC1441/LTC1442 are a family of micropower capacitor of up to 0.01µF without oscillation and by comparators with built-in 1.182V reference. Features inserting a series resistor, capacitance values up to 100µF include programmable hysteresis (LTC1440/LTC1442), can be used (Figure 1). wide supply voltage range (2V to 11V) and the ability of the Figure 2 shows the resistor value required for different reference to drive up to a 0.01µF capacitor without oscil- capacitor values to achieve critical damping. Bypassing lation. The comparators’ CMOS outputs can source up to the reference can help prevent false tripping of the com- 40mA and the supply current glitches, that normally occur parators by preventing glitches on V+ or reference load when switching logic states, have been eliminated. transients from disturbing the reference output voltage. Power Supplies Figure 3 shows the bypassed reference output with a square wave applied to the V+ pin. Resistors R2 and R3 set The comparator family operates from a single 2V to 11V 10mV of hysteresis voltage band while R1 damps the supply. The LTC1440 includes a separate ground for the reference response. Note that the comparator output comparator output stage, allowing a split supply ranging doesn’t trip. from ±1V to ±5.5V. Connecting V– to GND on the LTC1440 will allow single supply operation. If the comparator out- put is required to source more than 1mA, or the supply REFERENCE source impedance is high, V+ should be bypassed with a OUTPUT REF 0.1µF capacitor. R1 LTC144X Comparator Inputs C1 The comparator inputs can swing from the negative sup- V– ply V– to within 1.3V max of the positive supply V+. The inputs can be forced 300mV below V– or above V+ without 1440/1/2 F01 damage and the typical input leakage current is only Figure 1. Damping the Reference Output ±10pA. Comparator Outputs The LTC1440 comparator output swings between GND 1000 and V+ to assure TTL compatibility with a split supply. The LTC1441 and LTC1442 outputs swing between V– and V+. 100 )Ω The outputs are capable of sourcing up to 40mA and E (k U sinking up to 5mA while still maintaining microampere L VA 10 quiescent currents. The output stage does not generate R O T crowbar switching currents during transitions which helps SIS E minimize parasitic feedback through the supply pins. R 1 Voltage Reference 0.1 0.001 0.01 0.1 1 10 The internal bandgap reference has a voltage of 1.182V CAPACITOR VALUE (µF) referenced to V–. The reference accuracy is 1.5% from 1440/1/2 F02 –40°C to 85°C. It can source up to 200µA and sink up to Figure 2. Damping Resistance vs Bypass Capacitor Value 20µA with a 5V supply. The reference can drive a bypass 144012fd 10

LTC1440/LTC1441/LTC1442 APPLICATIOUNS INUFORWMATIOUN up to 15%. If hysteresis is not wanted, the HYST pin 7 should be shorted to REF. Acceptable values for I range V+ REF 3 IN+ + from 0.1µA to 5µA. If 2.4M is chosen for R2, then the value 8 OUT of R1 is equal to the value of VHB. 4 IN– – 5V 5 HYST 6 R1 = VHB TO IREF REF (2)(IREF) 8V 1R02k 6 REF LTC1440 R1 5 LTC1440 (1.182V – VHB) HYST R2 = 2 R3 R1 V– IREF R2 2.4M 430Ω V– GND 2 2 1 C1 1µF 1440/1/2 F04 1440/1/2 F03a Figure 4. Programmable Hysteresis Figure 3a. Reference Transient Response Test Circuit Level Detector The LTC1440 is ideal for use as a micropower level detector as shown in Figure 5. R1 and R2 form a voltage 8V divider from V to the noninverting comparator input. R3 V+ IN 5V and R4 set the hysteresis voltage, and R5 and C1 bypass V the reference output. The following design procedure can DI mV/ VREF be used to select the component values: 2 1. Choose the V voltage trip level, in this example 4.65V. IN OUT 2ms/DIV 1440/1/2 F03b VIN 5V Figure 3b. Reference and Comparator Output R2 7 Transient Response 3.4M V+ 1% 3 IN+ + Hysteresis R1 8 OUT 1.18M 4 IN– 1% – Hysteresis can be added to the LTC1440 by connecting a resistor (R1) between the REF and HYST pins and a 5 HYST second resistor (R2) from HYST to V– (Figure 4). R3 15k 1% 6 REF LTC1440 The difference between the upper and lower threshold voltages, or hysteresis voltage band (V ), is equal to twice R4 R5 the voltage difference between the REHFB and HYST pins. 21.%4M 453%0Ω V– GND C1 2 1 When more hysteresis is added, the upper threshold 1µF increases the same amount as the low threshold de- 1440/1/2 F05 creases. The maximum voltage allowed between REF and HYST pins is 50mV, producing a maximum hysteresis Figure 5. Glitch-Free Level Detector with Hysteresis voltage band of 100mV. The hysteresis band could vary by 144012fd 11

LTC1440/LTC1441/LTC1442 APPLICATIOUNS INUFORWMATIOUN 2. Calculate the required resistive divider ratio. ⎡ ⎤ Ratio = VREF/VIN ⎢ 4.65V ⎥ R2=1.18M⎢ −1⎥ Ratio = 1.182V/4.65V = 0.254 ⎢ 15mV ⎥ 1.182V+ ⎢ ⎥ 3. Choose the required hysteresis voltage band at the ⎣ 2 ⎦ input V , in this example 60mV. Calculate the hyster- R2=3.40M HBIN esis voltage band referred to the comparator input V . HB Low Voltage Operation V = (V )(Ratio) HB HBIN It is important to note that the voltage references internal V = (60mV)(0.254) HB to the LTC1440 and LTC1442 can exceed the common V = 15.24mV HB mode range of the comparators at low supply voltages. 4. Choose the values for R3 and R4 to set the hysteresis. The input common mode range of the LTC1440/LTC1441/ LTC1442 comparators is guaranteed to extend up to (V+ - R4 = 2.4M 1.3V). Therefore, if one of the comparator inputs is at the R3(kΩ) = V = 15k 1.182V reference voltage, the minimum supply voltage is HB 2.5V for a valid output reading. 5. Choose the values for R1 and R2 to set the trip point. The guaranteed minimum operating voltage for the V 1.182V LTC1440/LTC1441/LTC1442 is 2V (or ±1V). However, R1= REF = =1.18M both the reference and comparator(s) will function with a I 1µA BIAS supply voltage as low as 1.5V, but performance will ⎡ ⎤ degrade as the voltage goes below 2V. The voltage refer- ⎢ ⎥ V R2=R1⎢ IN −1⎥ ence temperature coefficient will degrade slightly, and the ⎢V + VHB ⎥ comparators will have less output drive with an increase in ⎣⎢ REF 2 ⎦⎥ propagation delay. At the reduced supply voltages, the input common mode range of the comparator(s) will still typically extend from the negative supply to approximately 1.1V below the positive supply. 144012fd 12

LTC1440/LTC1441/LTC1442 TYPICAL APPLICATIONUS 10-Bit 30µA A/D Converter 32.768kHz 1M 5V 470k + C2 1/2 LTC1441 5V EIN – 0V TO 3V 1.2M LT®1034 100k 1.2V 10pF 365k* + C1 2N3809 1/2 LTC1441 STATUS – VN2222LL 0.033µF 1N914 DATA 150k POLYSTYRENE 74C00 74C00 74C00 OUT 10M Q Q 74C74 74C00 D CLK CONV *TRW-IRC MRT–5/+120ppm/°C COMMAND 1440/1/2 TA03 32.768kHz “Watch Crystal” Oscillator 32.768kHz 1M +V 470k + 1/2 LTC1441 OUT – 1.2M 10pF 1440/1/2 TA05 144012fd 13

LTC1440/LTC1441/LTC1442 PACKAGE DESCRIPTIOU DD Package 8-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1698) R = 0.115 0.38 ± 0.10 TYP 5 8 0.675 ±0.05 3.5 ±0.05 1.65 ±0.05 3.00 ±0.10 1.65 ± 0.10 2.15 ±0.05 (2 SIDES) (4 SIDES) (2 SIDES) PIN 1 PACKAGE TOP MARK OUTLINE (NOTE 6) (DD8) DFN 1203 4 1 0.25 ± 0.05 0.200 REF 0.75 ±0.05 0.25 ± 0.05 0.50 0.50 BSC BSC 2.38 ±0.10 2.38 ±0.05 0.00 – 0.05 (2 SIDES) (2 SIDES) BOTTOM VIEW—EXPOSED PAD RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS NOTE: 1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-1) 2.DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6.SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON TOP AND BOTTOM OF PACKAGE MS8 Package 8-Lead Plastic MSOP (Reference LTC DWG # 05-08-1660) 0.889 ± 0.127 (.035 ± .005) 5.23 (.206) 3.20 – 3.45 MIN (.126 – .136) 3.00 ± 0.102 (.118 ± .004) 0.52 0.42 ± 0.038 0.65 (NOTE 3) 8 7 6 5 (.0205) (.0165 ± .0015) (.0256) REF TYP BSC RECOMMENDED SOLDER PAD LAYOUT 4.90 ± 0.152 3.00 ± 0.102 0.254 DETAIL “A” (.193 ± .006) (.118 ± .004) (NOTE 4) (.010) 0° – 6° 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 NOTE: (.009T Y– P.015) (.00.26556) (.0M0S5OP ±(M S.08) 002304) 1. DIMENSIONS IN MILLIMETER/(INCH) BSC 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 144012fd 14

LTC1440/LTC1441/LTC1442 PACKAGE DESCRIPTIOUN N8 Package 8-Lead PDIP (Narrow 0.300) (LTC DWG # 05-08-1510) .400* (10.160) MAX 8 7 6 5 .255 ± .015* (6.477 ± 0.381) 1 2 3 4 .300 – .325 .045 – .065 .130 ± .005 (7.620 – 8.255) (1.143 – 1.651) (3.302 ± 0.127) .065 (1.651) .008 – .015 TYP (0.203 – 0.381) .120 (3.048) .020 .325+–..003155 .100 .018 ± .0M0I3N (0M.5I0N8) ( +0.889) 8.255–0.381 (2B.S5C4) (0.457 ± 0.076) N8 1002 NOTE: INCHES 1. DIMENSIONS ARE MILLIMETERS *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm) 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 × 45° .053 – .069 (0.254 – 0.508) (1.346 – 1.752) .004 – .010 .008 – .010 (0.203 – 0.254) 0°– 8° 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 144012fd 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.

LTC1440/LTC1441/LTC1442 TYPICAL APPLICATIONU 10kHz V/F Converter +V 6.2V TO 12V LM334 2k* Q1 Q8 + 10kHz TRIM 2.2µF LT1034-1.2 200k + INPUT 1.2M* – LT1034-1.2 0.47µF 0V TO 5V C1 0.01µF 1/2 LTC1441 Q2 + 50pF Q3 100k Q4 2M TYP = HP5082-2810 100Hz TRIM 15k = 1N4148 Q7 Q5 = 2N2222 100pF** * = 1% METAL FILM fOUT 0kHz TO 10kHz ** = POLYSTYRENE Q6 10M 74C14 2.7M 0.1µF – C2 1/2 LTC1441 + 1440/1/2 TA04 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC1443 1.182V Reference with Micropower Quad Comparators 1% Accuracy, 8.5µA Maximum Current, Ref Output Drives 0.01µF LTC1444/LTC1445 1.2V Reference with Quad Comparator 1% Accuracy, 8.5µA Maximum Current, Ref Output Drives 0.01µF with Adjustable Hysteresis LTC1540 1.182V Reference with Nanopower Comparator DFN Package 0.3µA Quiescent Current (Typical), Reference with Adjustable Hysteresis Drives 0.01µF LTC1541 1.2V Reference with Micropower Amplifier and Comparator DFN Package 1.25% Accuracy, Rail-to-Rail Out, Low Offset Amplifier LTC1842/LTC1843 1.82V Reference with Dual Comparators 1% Accuracy, Open-Drain Out, Reference Drives 0.01µF with Adjustable Hysteresis LTC1998 1.2 Reference with Comparator with Adjustable Thesholds Li-Ion Low Battery Monitor, SOT23, 1% Accuracy LT6700-1 0.4 Reference with Low Voltage Dual Comparators SOT23, 1.4V to 18.5V Supply Range, ±2% Over Temperature LT6700-2/LT6700-3 144012fd 16 Linear Technology Corporation LT 0806 REV D • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 1996

Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: A nalog Devices Inc.: LTC1442CN8 LTC1441CS8 LTC1440CDD#TR LTC1440IMS8#PBF LTC1442IN8 LTC1440IN8#PBF LTC1442CS8#PBF LTC1440CMS8#TRPBF LTC1440IMS8#TR LTC1440IS8#TR LTC1441IS8 LTC1440CS8#TRPBF LTC1441IN8 LTC1440CS8#PBF LTC1440IS8#TRPBF LTC1440IDD LTC1440CN8 LTC1440IS8 LTC1440IDD#PBF LTC1440CMS8 LTC1441IS8#PBF LTC1442IN8#PBF LTC1442IS8 LTC1440IDD#TR LTC1440CDD#PBF LTC1441IS8#TR LTC1441IN8#PBF LTC1440IS8#PBF LTC1440IMS8#TRPBF LTC1440CMS8#PBF LTC1440IMS8 LTC1442CN8#PBF LTC1441IS8#TRPBF LTC1442CS8#TRPBF LTC1441CS8#TR LTC1442IS8#PBF LTC1442IS8#TRPBF LTC1440CMS8#TR LTC1442CS8 LTC1440CDD LTC1440CN8#PBF LTC1441CN8#PBF LTC1440CDD#TRPBF LTC1440IN8 LTC1441CS8#TRPBF LTC1442CS8#TR LTC1440CS8#TR LTC1441CN8 LTC1440CS8 LTC1442IS8#TR LTC1440IDD#TRPBF LTC1441CS8#PBF