LTC2910 Octal Positive/Negative Voltage Monitor FEATURES DESCRIPTION ■ 8 Low Voltage Adjustable Inputs (0.5V) The LTC®2910 is an octal input voltage monitor intended ■ Guaranteed Threshold Accuracy: ±1.5% for monitoring multiple voltages in a variety of applica- ■ Input Glitch Rejection tions. Each input has a nominal 0.5V threshold, featuring ■ Pin Selectable Input Polarity Allows 1.5% tight threshold accuracy over the entire operating Negative and OV Monitoring temperature range. Glitch fi ltering ensures reliable reset ■ Buffered 1V Reference Output operation without false or noisy triggering. ■ Adjustable Reset Timeout with Timeout Disable Polarity selection and a buffered reference allow monitor- ■ 50μA Quiescent Current ing up to two separate negative voltages. A three state ■ Open Drain RST and RST Outputs input pin allows setting the polarity of two inputs without ■ Guaranteed RST and RST for V ≥ 1V CC requiring any external components. ■ Available in 16-Lead SSOP and 16-Lead (5mm × 3mm) DFN Packages The LTC2910 provides a precise, versatile, space-con- scious, micropower solution for voltage monitoring. APPLICATIONS , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. ■ Desktop and Notebook Computers ■ Network Servers ■ Core, I/O Voltage Monitors TYPICAL APPLICATION Octal Supply Monitor, 10% Tolerance, 12V, 5V (x2), 3.3V (x2), 2.5V, 1.8V, 1.2V Typical Transient Duration vs Comparator Overdrive 12V 700 5V 3.3V μs)600 2.5V ON ( POWER TI500 SUPPLIES 1.8V RA RESET OCCURS U ABOVE CURVE 1.2V T D400 N 5V E SI300 3.3V AN R L T200 11k 54.191kk 88.171kk 12.171kk 24.191kk 39.121kk 54.191kk 88.171kk 226k SYSTEM YPICA100 VCC = 6V T VCC = 2.3V 0 0.1 1 10 100 V8 V7 V6 V5 V4 V3 V2 V1 COMPARATOR OVERDRIVE PAST THRESHOLD (%) 0.1μF LTC2910 VCC 2910 TA01b GND TMR DIS RST RST SEL 1nF TIMEOUT = 8.5ms 2910 TA01 2910fc 1

LTC2910 ABSOLUTE MAXIMUM RATINGS (Note 1, 2) Terminal Voltages Operating Temperature Range V (Note 3) .............................................–0.3V to 6V LTC2910C ................................................0°C to 70°C CC RST, RST ................................................–0.3V to 16V LTC2910I..............................................–40°C to 85°C TMR ..........................................–0.3V to (V + 0.3V) LTC2910H ..........................................–40°C to 125°C CC Vn, DIS, SEL .........................................–0.3V to 7.5V Storage Temperature Range Terminal Current SSOP, DFN ..........................................–65°C to 150°C I ....................................................................10mA Lead Temperature (Soldering, 10 sec) VCC Reference Load Current (I ) ...........................±1mA SSOP ................................................................300°C REF I ..............................................................10mA RST/RST PACKAGE/ORDER INFORMATION TOP VIEW TOP VIEW V1 1 16 VCC V1 1 16 VCC V2 2 15 TMR V2 2 15 TMR V3 3 14 SEL V3 3 14 SEL V4 4 13 DIS 17 V4 4 13 DIS V5 5 12 RST V5 5 12 RST V6 6 11 RST V6 6 11 RST V7 7 10 REF V7 7 10 REF V8 8 9 GND V8 8 9 GND DHC16 PACKAGE GN16 PACKAGE 16-LEAD (5mm × 3mm) PLASTIC DFN 16-LEAD PLASTIC SSOP EXPOSED PADT J(MPIANX 1=7 1)5 P0C°BC ,G θNJAD =C 4O3N.5N°ECC/TWION OPTIONAL TJMAX = 150°C, θJA = 110°C/W ORDER PART NUMBER DHC16 PART MARKING* ORDER PART NUMBER GN16 PART MARKING* LTC2910CDHC 2910 LTC2910CGN 2910 LTC2910IDHC 2910 LTC2910IGN 2910I LTC2910HDHC 2910 LTC2910HGN 2910H 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/ *The temperature grade is identifi ed by a label on the shipping container. ELECTRICAL CHARACTERISTICS The ● denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at T = 25°C. V = 3.3V, Vn = 0.55V, SEL = V , DIS = OPEN unless otherwise noted. A CC CC (Note 2) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V V Shunt Regulator Voltage I = 5mA ● 6.2 6.6 6.9 V SHUNT CC CC –40°C < T <125°C ● 6.2 6.6 7.0 V A ΔVSHUNT VCC Shunt Regulator Load Regulation ICC = 2mA to 10mA ● 200 300 mV V Supply Voltage ● 2.3 V V CC SHUNT 2910fc 2

LTC2910 ELECTRICAL CHARACTERISTICS The ● denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at T = 25°C. V = 3.3V, Vn = 0.55V, SEL = V , DIS = OPEN unless otherwise noted. A CC CC (Note 2) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V Minimum V Output Valid DIS = 0V ● 1 V CC(MIN) CC V Supply Undervoltage Lockout V Rising, DIS = 0V ● 1.9 2 2.1 V CC(UVLO) CC ΔVCC(UVHYST) Supply Undervoltage Lockout Hysteresis DIS = 0V ● 5 25 50 mV I Supply Current V = 2.3V to 6V ● 50 100 μA CC CC V Reference Output Voltage I = ±1mA ● 0.985 1 1.015 V REF VREF –40°C < T < 125°C ● 0.985 1 1.020 V A V Vn Input Voltage Threshold ● 492 500 508 mV RT t Vn Input Threshold to Output Delay V = V – 5mV ● 50 125 500 μs PROP n RT I Vn Input Current ● ±15 nA VN –40°C < T < 125°C ● ±30 nA A t Reset Timeout Period C = 1nF ● 6 8.5 12.5 ms RST TMR –40°C < T < 125°C ● 6 8.5 14 ms A V DIS Input Threshold Voltage High ● 1.2 V DIS(VIH) V DIS Input Threshold Voltage Low ● 0.8 V DIS(VIL) I DIS Input Current V > 0.5V ● 1 2 3 μA DIS DIS I TMR Pull-Up Current V = 0V ● –1.3 –2.1 –2.8 μA TMR(UP) TMR –40°C < T < 125°C ● –1.2 –2.1 –2.8 μA A I TMR Pull-Down Current V = 1.6V ● 1.3 2.1 2.8 μA TMR(DOWN) TMR –40°C < T < 125°C ● 1.2 2.1 2.8 μA A V Timer Disable Voltage Referenced to V ● –180 –270 mV TMR(DIS) CC V Output Voltage High RST/RST V = 2.3V, I = –1μA ● 1 V OH CC RST/RST V Output Voltage Low RST/RST V = 2.3V, I = 2.5mA ● 0.1 0.3 V OL CC RST/RST V = 1V, I = 100μA 0.01 0.15 V CC RST Three-State Input SEL V Low Level Input Voltage ● 0.4 V IL V High Level Input Voltage ● 1.4 V IH V Pin Voltage when Left in Hi-Z State I = ±10μA ● 0.6 0.9 1.1 V Z SEL –40°C < T < 125°C ● 0.6 0.9 1.2 V A I SEL High, Low Input Current ● ±25 μA SEL I Maximum SEL Input Current SEL tied to either V or GND ● ±30 μA SEL(MAX) CC Note 1: Stresses beyond those listed under Absolute Maximum Ratings Note 3: V maximum pin voltage is limited by input current. Since the CC may cause permanent damage to the device. Exposure to any Absolute V pin has an internal 6.5V shunt regulator, a low impedance supply that CC Maximum Rating condition for extended periods may affect device exceeds 6V may exceed the rated terminal current. Operation from higher reliability and lifetime. voltage supplies requires a series dropping resistor. See Applications Note 2: All currents into pins are positive; all voltages are referenced to Information. GND unless otherwise noted. 2910fc 3

LTC2910 TIMING DIAGRAM Vn Positive Monitor Timing Vn VRT tRST tPROP RST 1V RST 1V 2910 TD01 Vn Positive Monitor Timing (TMR strapped to V ) CC Vn VRT tPROP tPROP RST 1V RST 1V 2910 TD03 Vn Negative Monitor Timing Vn VRT tRST tPROP RST 1V RST 1V 2910 TD02 Vn Negative Monitor Timing (TMR strapped to V ) CC Vn VRT tPROP tPROP RST 1V RST 1V 2910 TD04 2910fc 4

LTC2910 TYPICAL PERFORMANCE CHARACTERISTICS Specifi cations are at T = 25°C and V = 3.3V A CC unless otherwise noted. (Note 2) Input Threshold Voltage vs V Shunt Voltage vs CC Temperature Supply Current vs Temperature Temperature 0.505 65 6.8 0.504 E, V (V)RT00..550032 6505 VCC = 5V 66..67 150mmAA G0.501 LD VOLTA00..459090 I (μA)CC 50 VCC = 3.3V V (V)CC 6.5 12mmAA SHO0.498 45 6.4 E THR0.497 40 VCC = 2.3V 6.3 200μA 0.496 0.495 35 6.2 –50 –25 0 25 50 75 100 –50 –25 0 25 50 75 100 –50 –25 0 25 50 75 100 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) 2910 G01 2910 G02 2910 G03 Buffered Reference Voltage vs Transient Duration vs Comparator V Shunt Voltage vs I Temperature Overdrive CC CC 6.75 1.005 700 6.65 (V)REF111...000000324 TION (μs) 560000 V A RESET OCCURS V (V)CC66..4555 25°C E VOLTAGE, 011...900900910 NSIENT DUR 430000 ABOVE CURVE –40°C NC RA 6.35 85°C REFERE 00..999978 PICAL T 200 VCC = 6V Y 100 0.996 T VCC = 2.3V 6.25 0.995 0 –2 0 2 4 6 8 10 12 –50 –25 0 25 50 75 100 0.1 1 10 100 ICC (mA) TEMPERATURE (°C) COMPARATOR OVERDRIVE PAST THRESHOLD (%) 2910 G04 2910 G05 2910 G06 Reset Time-Out Period vs Temperature RST Output Voltage vs V RST Output Voltage vs V CC CC 12 0.8 5 CTMR = 1nF Vn = 0.55V ms)11 VCC SEL = VCC (ST 0.6 4 R D, t10 V) V) UT PERIO 9 OLTAGE (0.4 OLTAGE ( 3 O V RST WITH V TIME 8 RST 10k PULL-UP RST 2 ST 0.2 T/R 7 RST WITHOUT 1 S 10k PULL-UP R 6 0 0 –50 –25 0 25 50 75 100 0 0.2 0.4 0.6 0.8 1.0 0 1 2 3 4 5 TEMPERATURE (°C) SUPPLY VOLTAGE, VCC (V) SUPPLY VOLTAGE, VCC (V) 2910 G07 2910 G08 2910 G09 2910fc 5

LTC2910 TYPICAL PERFORMANCE CHARACTERISTICS Specifi cations are at T = 25°C and V = 3.3V A CC unless otherwise noted. (Note 2) RST/RST Voltage Output Low vs Reset Timeout Period vs RST, I vs V Output Sink Current Capacitance SINK CC 5 1.0 10000 Vn = 0.45V A) SEL = VCC 85°C ms) N CURRENT, I (mRST423 RST AT 150mV T/RST, V (V)OL 000...468 25°C –40°C EOUT PERIOD, t (RST1100000 OW RST AT 50mV RS TIM PULL-D 1 0.2 ST/RST 10 R 0 0 1 0 1 2 3 4 5 0 5 10 15 20 25 30 0.1 1 10 100 1000 SUPPLY VOLTAGE, VCC (V) IRST/RST (mA) TMR PIN CAPACITANCE, CTMR (nF) 2910 G10 2910 G11 2910 G12 PIN FUNCTIONS DIS (Pin 13): Output Disable Input. Disables the RST and RST (Pin 12): Open-Drain Inverted Reset Logic Output. RST output pins. When DIS is pulled high, the RST and Asserts low when any positive polarity input voltage is RST pins are not asserted except during a UVLO condition. below threshold or any negative polarity input voltage is Pin has a weak (2μA) internal pull-down to GND. Leave above threshold. Held low for an adjustable delay time after pin open if unused. all voltage inputs are valid. Pin has a weak pull-up to V CC and may be pulled above V using an external pull-up. Exposed Pad (Pin 17, DFN Package): Exposed pad may CC Leave pin open if unused. be left open or connected to device ground. SEL (Pin 14): Input Polarity Select Three-State Input. GND (Pin 9): Device Ground Connect to V , GND or leave unconnected in open state CC REF (Pin 10): Buffered Reference Output. 1V reference to select one of three possible input polarity combinations used for the offset of negative-monitoring applications. (refer to Table 1). The buffered reference sources and sinks up to 1mA. The TMR (Pin 15): Reset Delay Timer. Attach an external ca- reference drives capacitive loads up to 1nF. Larger capacitive pacitor (C ) of at least 10pF to GND to set a reset delay loads may cause instability. Leave pin open if unused. TMR time of 9ms/nF. A 1nF capacitor will generate an 8.5ms RST (Pin 11): Open-Drain Reset Logic Output. Asserts reset delay time. Tie pin to V to bypass timer. CC high when any positive polarity input voltage is below V1-V6 (Pin 1, 2, 3, 4, 5 & 6): Voltage Inputs 1 through 6. threshold or any negative polarity input voltage is above When the voltage on this pin is below 0.5V, a reset condi- threshold. Held high for an adjustable delay time after all tion is triggered. Tie pin to V if unused. voltage inputs are valid. Pin has a weak pull-up to V and CC CC may be pulled above V using an external pull-up. Leave V7-V8 (Pin 7 & 8): Voltage Inputs 7 and 8. The polarity CC pin open if unused. of the input is selected by the state of the SEL pin (refer 2910fc 6

LTC2910 PIN FUNCTIONS to Table 1). When the monitored input is confi gured as a V (Pin 16): Supply Voltage. Bypass this pin to GND with CC positive voltage, a reset condition is triggered when the a 0.1μF (or greater) capacitor. Operates as a direct supply pin is below 0.5V. When the monitored input is confi g- input for voltages up to 6V. Operates as a shunt regulator for ured as a negative voltage, a reset condition is triggered supply voltages greater than 6V and must have a resistance when the pin is above 0.5V. Tie pin to V if unused and between the pin and the supply to limit input current to no CC confi gured as a positive supply. Tie pin to GND if unused greater than 10mA. When used without a current-limiting and confi gured as a negative supply. resistance, pin voltage must not exceed 6V. BLOCK DIAGRAM VCC TMR 16 15 1 V1 – VCC + OSCILLATOR 400k V2 2 – RST RESET DELAY 12 + TIMER DISABLE V3 3 – + + 2V VCC UVLO V4 – VCC 400k 4 – + RST 11 V5 5 – + V6 6 – + V7 7 – + + DIS 13 – 1V V8 2μA 8 – + 0.5V REF THREE-STATE GND 10 1V POLARITY 9 DECODER BUFFER 14 2910 BD SEL 2910fc 7

LTC2910 APPLICATIONS INFORMATION Voltage Monitoring Table 1. Voltage Polarity Programming (V = 0.5V Typical) RT The LTC2910 is a low power octal voltage monitoring SEL V7 INPUT V8 INPUT circuit with eight individual undervoltage monitor inputs. V Positive Positive CC A timeout period that holds a reset after all faults have V7 < VRT → UV V8 < VRT → UV cleared is adjustable using an external capacitor and is Open Positive Negative V7 < VRT → UV V8 > VRT → UV disabled, by tying TMR to V . CC GND Negative Negative Each voltage monitor is compared to a fi xed 0.5V reference V7 > VRT → UV V8 > VRT → UV for detecting undervoltage conditions. When confi gured 2-Step Design Procedure to monitor a positive voltage V , the application is con- m nected as shown in Figure 1. For negative inputs V is The following 2-step design procedure allows selecting m connected as shown in Figure 2. R is now connected to appropriate resistances to obtain the desired UV trip point A the REF pin and R remains connected to the monitored for the positive voltage monitor circuit in Figure 1 and the B voltage V . negative voltage monitor circuit in Figure 2. m Using the confi gurations in Figures 1 and 2, a UV condi- For positive supply monitoring, Vm is the desired nominal tion will result when the magnitude of the voltage at Vm operating voltage, Im is the desired nominal current through is less than its designed threshold. the resistive divider, and VUV is the desired undervoltage trip point. Polarity Selection For negative supply monitoring, to compensate for the 1V The three-state polarity-select pin (SEL) selects one of three reference, 1V must be subtracted from V and V before m UV possible polarity combinations for the input thresholds, using each in the following equations. as described in Table 1. When an input is confi gured for negative supply monitoring, a reset condition occurs when 1. Choose RA to obtain the desired UV trip point the supply voltage is less negative than the confi gured R is chosen to set the desired trip point for the A threshold. undervoltage monitor. The three-state input pin SEL is connected to GND, V , or CC 0.5V V left unconnected during normal operation. When the pin R = (cid:129) m (1) A is left unconnected, the maximum leakage allowed from Im VUV the pin is ±10μA to ensure it remains in the open state. Table 1 shows the three possible selections of polarity based on the SEL pin connection. LTC2910 REF + + Vm – – 1V RB RA LTC2910 Vn Vn – – UVn UVn + + RA + RB + – 0.5V – 0.5V Vm 2910 F01 2910 F02 Figure 1. Positive UV Monitoring Confi guration Figure 2. Negative UV Monitoring Confi guration 2910fc 8

LTC2910 APPLICATIONS INFORMATION 2. Choose R to complete the design current in the resistive divider is 10μA. For the negative B case, 1V is subtracted from V and V . Once R is known, R is determined by: m UV A B 1. Find R to set the UV trip point of the monitor. A V R = m −R (2) B I A 0.5V –5V−1V m RA = (cid:129) ≈54.9k 10µA –4.5V−1V If any of the variables V , I , or V change, then both m m UV steps must be recalculated. 2. Determine RB to complete the design. –5V−1V Positive Voltage Monitor Example R = −57.6k≈549k B 10µA A positive voltage monitor application is shown in Figure 3. The monitored voltage is a 5V ±10% supply. Nominal Power-Up/Down current in the resistive divider is 10μA. As soon as V reaches 1V during power up, the RST output 1. Find R to set the UV trip point of the monitor. CC A asserts low and the RST output weakly pulls to V . CC 0.5V 5V R = (cid:129) ≈56.2k The LTC2910 is guaranteed to assert RST low and RST high A 10µA 4.5V under conditions of low VCC, down to VCC = 1V. Above VCC = 2V (2.1V maximum) the Vn inputs take control. 2. Determine R to complete the design. B Once all inputs and V become valid, an internal timer is CC 5V started. After an adjustable delay time, RST pulls low and R = −56.2k≈499k B 10µA RST weakly pulls high. Threshold Accuracy Negative Voltage Monitor Example Reset threshold accuracy is important in a supply sensitive A negative voltage monitor application is shown in Figure system. Ideally, such a system would reset only if supply 4. The monitored voltage is a –5V ±10% supply. Nominal 5V 5V VCC VCC 5V ± 10% RST RST REF RB RST RA RST 449k LTC2910 54.9k LTC2910 V7 V7 RA SEL RB SEL 56.2k 549k GND –5V ± 10% GND 2910 F03 2910 F04 Figure 3. Positive Supply Monitor Figure 4. Negative Supply Monitor 2910fc 9

LTC2910 APPLICATIONS INFORMATION voltages fell below the exact threshold for a specifi ed mar- Glitch Immunity gin. All LTC2910 inputs have a relative threshold accuracy In any supervisory application, noise riding on the moni- of ±1.5% over the full operating temperature range. tored DC voltage causes spurious resets. To solve this For example, when the LTC2910 is programmed to moni- problem without adding hysteresis, which causes a new tor a 5V input with a 10% tolerance, the desired UV trip error term in the trip voltage, the LTC2910 lowpass fi lters point is 4.5V. Because of the ±1.5% relative accuracy of the output of the fi rst stage comparator at each input. the LTC2910, the UV trip point is between 4.433V and This fi lter integrates the output of the comparator before 4.567V which is 4.5V ±1.5%. asserting the reset output logic. A transient at the input of the comparator of suffi cient magnitude and duration The accuracy of the resistances chosen for R and R affect A B triggers the output logic. The Typical Performance Char- the UV trip point as well. Using the example just given, acteristics section shows a graph of the Transient Duration if the resistances used to set the UV trip point have 1% vs. Comparator Overdrive. accuracy, the UV trip range is between 4.354V and 4.650V. This is illustrated in the following calculations. RST/RST Timing The UV trip point is given as The LTC2910 has an adjustable timeout period (t ) that RST holds RST and RST asserted after all faults have cleared. (cid:1) R (cid:4) V =0.5V(cid:129) 1+ B This assures a minimum reset pulse width allowing a UV (cid:2) (cid:5) (cid:3) R (cid:6) A settling time delay for the monitored voltage after it has entered the valid region of operation. The two extreme conditions, with a relative accuracy of 1.5% and resistance accuracy of 1%, result in When any input drops below its designed threshold, the RST pin asserts low and the RST pin asserts high. When (cid:1) R (cid:129)0.99(cid:4) V =0.5V(cid:129)0.985(cid:129) 1+ B all inputs recover above their designed thresholds, the UV(MIN) (cid:2) (cid:5) (cid:3) R (cid:129)1.01(cid:6) reset delay timer starts. If all inputs remain above their A designed thresholds when the timer fi nishes, the RST and pin weakly pulls high and the RST pin strongly pulls low. V =0.5V(cid:129)1.015(cid:129)(cid:1)1+ RB(cid:129)1.01(cid:4) However, if any input falls below its designed threshold UV(MAX) (cid:2) (cid:5) (cid:3) R (cid:129)0.99(cid:6) during this timeout period, the timer resets and restarts A when all inputs are above the designed thresholds. R For a desired trip point of 4.5V, B =8 Selecting the Reset Timing Capacitor R A The reset timeout period (t ) for the LTC2910 is adjust- Therefore, RST able to accommodate a variety of applications. Connecting (cid:1) 0.99(cid:4) a capacitor, C , between the TMR pin and ground sets V =0.5V(cid:129)0.985(cid:129) 1+8(cid:129) =4.354V TMR UV(MIN) (cid:2) (cid:5) (cid:3) 1.01(cid:6) the timeout period. The value of capacitor needed for a and particular timeout period is: (cid:1) 1.01(cid:4) CTMR = tRST • 115 • 10–9 (F/s) V =0.5V(cid:129)1.015(cid:129) 1+8(cid:129) =4.650V UV(MAX) (cid:2) (cid:5) (cid:3) 0.99(cid:6) The Reset Timeout Period vs. Capacitance graph found in the Typical Performance Characteristics section shows 2910fc 10

LTC2910 APPLICATIONS INFORMATION the desired delay time as a function of the value of the At V = 1V, the weak pull-up current on RST is barely CC timer capacitor. The TMR pin must have a minimum of turned on. Therefore, an external pull-up resistor of no more 10pF or be tied to V . For long timeout periods, the only than 100k is recommended on the RST pin if the state and CC limitation is the availability of a large value capacitor with pull-up strength of the RST pin is crucial at very low V . CC low leakage. Capacitor leakage current must not exceed Note however, by adding an external pull-up resistor, the the minimum TMR charging current of 1.3μA. Tying the pull-up strength on the RST pin is increased. Therefore, TMR pin to V bypasses the timeout period. if it is connected in a wired-OR connection, the pull-down CC strength of any single device must accommodate this ad- Undervoltage Lockout ditional pull-up strength. When V falls below 2V, the LTC2910 asserts an CC Output Rise and Fall Time Estimation undervoltage lockout (UVLO) condition. During UVLO, RST is asserted and pulled low and RST is pulled high. When The RST and RST outputs have strong pull-down capabil- V rises above 2V, RST and RST follow the same timing ity. The following formula estimates the output fall time CC procedure as an undervoltage condition on any input. (90% to 10%) for a particular external load capacitance (C ): LOAD Shunt Regulator t ≈ 2.2 • R • C FALL PD LOAD The LTC2910 has an internal shunt regulator. The V pin CC where R is the on-resistance of the internal pull-down operates as a direct supply input for voltages up to 6V. PD transistor, typically 50Ω at V > 1V, and at room tem- In this range, the quiescent current of the device remains CC perature (25°C). C is the external load capacitance below a maximum of 100μA. For V voltages higher than LOAD CC on the pin. Assuming a 150pF load capacitance, the fall 6V, the pin functions as a shunt regulator and must have a time is 16.5ns. resistance R between the supply and the V pin to limit Z CC the current to no greater than 10mA. The rise time on the RST and RST pins is limited by a 400k internal pull-up resistance to V . A similar formula When selecting this resistance value, choose an appropriate CC estimates the output rise time (10% to 90%) at the RST location on the I-V curve shown in the Typical Performance and RST pins: Characteristics to accommodate any variations in V due CC to changes in current through R . t ≈ 2.2 • R • C Z RISE PU LOAD where R is the pull-up resistance. RST/RST Output Characteristics PU The DC characteristics of the RST and RST pull-up and Disable pull-down strength are shown in the Typical Performance The LTC2910 allows disabling the RST and RST outputs Characteristics. Each has a weak internal pull-up to V and CC via the DIS pin. Pulling DIS high forces both outputs to a strong pull-down to ground. This arrangement allows remain unasserted, regardless of any faults that occur each pin to have open-drain behavior while possessing on the inputs. However, if a UVLO condition occurs, RST several other benefi cial characteristics. The weak pull-up asserts and pulls low, RST asserts and pulls high, but the eliminates the need for an external pull-up resistor when timeout function is bypassed. RST pulls high and RST pulls the rise time on this pin is not critical. On the other hand, low as soon as the UVLO condition is cleared. the open drain confi guration allows for wired-OR connec- tions and is useful when more than one signal needs to DIS has a weak 2μA (typical) internal pull-down current pull down on the RST or RST lines. V of 1V guarantees guaranteeing normal operation with the pin left open. CC a maximum V = 0.15V. OL 2910fc 11

LTC2910 TYPICAL APPLICATIONS Eight UV Supply Monitor, 10% Tolerance, 12V, 5V (x2), 3.3V (x2), 2.5V, 1.8V, 1.2V 12V 5V 3.3V 2.5V POWER SUPPLIES 1.8V 1.2V 5V 3.3V RB8 RB7 RB6 RB5 RB4 RB3 RB2 RB1 54.9k 88.7k 12.7k 24.9k 39.2k 54.9k 88.7k 226k SYSTEM RA8 RA7 RA6 RA5 RA4 RA3 RA2 RA1 11k 11k 11k 11k 11k 11k 11k 11k 8 7 6 5 4 3 2 1 V8 V7 V6 V5 V4 V3 V2 V1 LTC2910 VCC 16 C0.B1YμPF GND TMR DIS RST RST SEL 9 15 13 12 11 14 CTMR 1nF TIMEOUT = 8.5ms 2910 TA02 Six Positive and Two Negative UV Supply Monitor, 10% Tolerance, 12V, 5V, 3.3V, 2.5V, 1.8V, 1.2V, –5V, –3.3V 12V 5V 3.3V POWER 2.5V SUPPLIES 1.8V 1.2V RB8 RB7 RB6 RB5 RB4 RB3 RB2 RB1 54.9k 11k 12.7k 24.9k 39.2k 54.9k 88.7k 226k RA8 RA7 RA6 RA5 RA4 RA3 RA2 RA1 107k 11k 11k 11k 11k 11k 11k 11k SYSTEM 8 7 10 6 5 4 3 2 1 V8 V7 REF V6 V5 V4 V3 V2 V1 16 LTC2910 VCC CBYP 0.1μF GND TMR DIS RST RST SEL 9 15 13 12 11 14 CTMR 22nF TIMEOUT = 200ms –3.3V –5V 2910 TA03 2910fc 12

LTC2910 TYPICAL APPLICATIONS Six UV and One OV/UV Supply Monitor, 10% Tolerance, 12V, 5V, 3.3V (x2), 2.5V, 1.8V, 1.2V 12V 5V 3.3V POWER 2.5V SUPPLIES 1.8V 1.2V 3.3V RB7 RB6 RB5 RB4 RB3 RB2 RB1 27.4k 12.7k 24.9k 39.2k 54.9k 88.7k 226k RA8 RA7 RA6 RA5 RA4 RA3 RA2 RA1 4.53k 1k 11k 11k 11k 11k 11k 11k SYSTEM 8 7 6 5 4 3 2 1 V8 V7 V6 V5 V4 V3 V2 V1 16 LTC2910 VCC CBYP GND TMR DIS RST RST SEL 0.1μF 9 15 13 12 11 14 CTMR 1nF TIMEOUT = 8.5ms 2910 TA04 Six UV Supply Monitor Powered from 48V, 10% Tolerance, 48V, 5V, 3.3V, 2.5V, 1.8V, 1.2V 48V 5V 3.3V POWER 2.5V SUPPLIES 1.8V 1.2V RB6 RB5 RB4 RB3 RB2 RB1 12.7k 24.9k 39.2k 54.9k 88.7k 953k RA6 RA5 RA4 RA3 RA2 RA1 11k 11k 11k 11k 11k 11k RZ SYSTEM 8.25k 8 7 6 5 4 3 2 1 V8 V7 V6 V5 V4 V3 V2 V1 16 LTC2910 VCC CBYP GND TMR DIS RST RST SEL 0.1μF 9 15 13 12 11 14 VCC 2910 TA05 2910fc 13

LTC2910 TYPICAL APPLICATIONS Eight UV Supply Monitor with Manual Reset Button, 10% Tolerance, 12V, 5V (x2), 3.3V (x2), 2.5V, 1.8V, 1.2V 12V 5V 3.3V 2.5V POWER 1.8V SUPPLIES 1.2V 5V 3.3V RB8 RB7 RB6 RB5 RB4 RB3 RB2 RB1 RPB 549k 88.7k 12.7k 24.9k 39.2k 54.9k 88.7k 226k MANUAL 10k RESET BUTTON SYSTEM (NORMALLY OPEN) RA8 RA7 RA6 RA5 RA4 RA3 RA2 RA1 110k 11k 11k 11k 11k 11k 11k 11k 8 7 6 5 4 3 2 1 V8 V7 V6 V5 V4 V3 V2 V1 LTC2910 VCC 16 C0.B1YμPF GND TMR DIS RST RST SEL 9 15 13 12 11 14 CTMR 22nF TIMEOUT = 200ms 2910 TA06 2910fc 14

LTC2910 PACKAGE DESCRIPTION DHC Package 16-Lead Plastic DFN (5mm × 3mm) (Reference LTC DWG # 05-08-1706) 5.00 ±0.10 R = 0.T1Y1P5 0.40 ± 0.10 (2 SIDES) 9 16 R = 0.20 0.65 ±0.05 TYP 3.00 ±0.10 (2 SIDES) 3.50 ±0.05 1.65 ±0.05 1.65 ± 0.10 (2 SIDES) PACKAGE (2 SIDES) 2.20 ±0.05 OUTLINE PIN 1 PIN 1 TOP MARK NOTCH (SEE NOTE 6) (DHC16) DFN 1103 8 1 0.25 ± 0.05 0.200 REF 0.75 ±0.05 0.25 ± 0.05 0.50 BSC 0.50 BSC 4.40 ±0.05 4.40 ±0.10 (2 SIDES) 0.00 – 0.05 (2 SIDES) BOTTOM VIEW—EXPOSED PAD RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS NOTE: 1. DRAWING PROPOSED TO BE MADE VARIATION OF VERSION (WJED-1) IN JEDEC 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE PACKAGE OUTLINE MO-229 MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 2. DRAWING NOT TO SCALE 5. EXPOSED PAD SHALL BE SOLDER PLATED 3. ALL DIMENSIONS ARE IN MILLIMETERS 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE GN Package 16-Lead Plastic SSOP (Narrow .150 Inch) (Reference LTC DWG # 05-08-1641) .189 – .196* (4.801 – 4.978) .009 .015 ± .004 × 45°(cid:31) .0532 – .0688 .004 – .0098 16 1514 1312 11109 (0R.2E2F9) .045 ±.005 (0.38 ± 0.10) 0° – 8° (1.35 – 1.75) (0.102 – 0.249) .007 – .0098 TYP (0.178 – 0.249) .016 – .050 .008 – .012 .0250 .229 – .244 .150 – .157** .254 MIN .150 – .165 (0.406 – 1.270) (0.203 – 0.305) (0.635) (5.817 – 6.198) (3.810 – 3.988) TYP BSC NOTE: 1. CONTROLLING DIMENSION: INCHES 3. DRAWING NOT TO SCALE 2. DIMENSIONS ARE IN INCHES *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH 1 2 3 4 5 6 7 8 .0165 ±.0015 .0250 BSC (MILLIMETERS) SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE RECOMMENDED SOLDER PAD LAYOUT **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE GN16 (SSOP) 0204 2910fc 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 representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.

LTC2910 TYPICAL APPLICATION Eight UV Supply Monitor with LED Indicator, 10% Tolerance, 12V, 5V (x2), 3.3V (x2), 2.5V, 1.8V, 1.2V 12V 5V 3.3V 2.5V POWER 1.8V SUPPLIES 1.2V 5V 3.3V 54.9k 88.7k 12.7k 24.9k 39.2k 54.9k 88.7k 226k 11k 11k 11k 11k 11k 11k 11k 11k SYSTEM 8 7 6 5 4 3 2 1 V8 V7 V6 V5 V4 V3 V2 V1 16 0.1μF LTC2910 VCC GND TMR DIS RST RST SEL 9 15 13 12 11 14 1nF TIMEOUT = 8.5ms 2910 TA07 510μΩ VCC RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC690 5V Supply Monitor, Watchdog Timer and Battery Backup 4.65V Threshold LTC694-3.3 3.3V Supply Monitor, Watchdog Timer and Battery 2.9V Threshold Backup LTC2900 Programmable Quad Supply Monitor Adjustable RESET , 10-Lead MSOP and 3mm × 3mm 10-Lead DFN Package LTC2901 Programmable Quad Supply Monitor Adjustable RESET and Watchdog Timer, 16-Lead SSOP Package LTC2902 Programmable Quad Supply Monitor Adjustable RESET and Tolerance, 16-Lead SSOP Package, Margining Functions LTC2903 Precision Qual Supply Monitor 6-Lead SOT-23 Package, Ultra Low Voltage Reset LTC2904 3-State Programmable Precision Dual Supply Monitor Adjustable Tolerance, 8-Lead SOT-23 Package LTC2905 3-State Programmable Precision Dual Supply Monitor Adjustable RESET and Tolerance, 8-Lead SOT-23 Package LTC2906 Precision Dual Supply Monitor One Selectable and One Separate V Pin, RST/RST Outputs CC Adjustable LTC2907 Precision Dual Supply Monitor One Selectable and One Separate V , Adjustable Reset Timer CC Adjustable LTC2908 Precision Six Supply Monitor (Four Fixed and Two 8-Lead SOT-23 and DDB Packages Adjustable) LTC2909 Prevision Dual Input UV, OV and Negative Voltage Monitor Separate V Pin, Adjustable Reset Timer, 8-Lead SOT-23 and DDB CC Packages LTC2914 Quad UV/OV Positive/Negative Voltage Monitor Separate V Pin, Four Inputs, Up to Two Negative Monitors, CC Adjustable Reset Timer, 16-Lead SSOP and DFN Packages 2910fc 16 Linear Technology Corporation LT 1007 REV C • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2006

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