How To Power A Power Generator With A Power Supply From A Powerstation

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1 LT636 Over-The-Top Micropower Rail-to-Rail Input and Output Op Amp FEATRES Rail-to-Rail Input and Output Micropower: 5µA I Q, 44V Supply Operating Temperature Range: 4 C to 25 C Over-The-Top : Input Common Mode Range Extends 44V Above V EE, Independent of V CC Low Input Offset Voltage: 225µV Max Specified on 3V, 5V and ±5V Supplies High Output Current: 8mA Output Shutdown Output Drives,pF with Output Compensation Reverse Battery Protection to 27V High Voltage Gain: 2V/mV High CMRR: db 22kHz Gain-Bandwidth Product 8-Lead DFN, MSOP, PDIP and SO Packages APPLICATIO S Battery- or Solar-Powered Systems Portable Instrumentation Sensor Conditioning Supply Current Sensing Battery Monitoring MX Amplifiers 4mA to 2mA Transmitters DESCRIPTIO The LT 636 op amp operates on all single and split supplies with a total voltage of 2.7V to 44V drawing less than 5µA of quiescent current. The LT636 can be shut down, making the output high impedance and reducing the quiescent current to 4µA. The LT636 has a unique input stage that operates and remains high impedance when above the positive supply. The inputs take 44V both differential and common mode, even when operating on a 3V supply. The output swings to both supplies. nlike most micropower op amps, the LT636 can drive heavy loads; its rail-to-rail output drives 8mA. The LT636 is unity-gain stable into all capacitive loads up to,pf when a.22µf and 5Ω compensation network is used. The LT636 is reverse supply protected: it draws no current for reverse supply up to 27V. Built-in resistors protect the inputs for faults below the negative supply up to 22V. There is no phase reversal of the output for inputs 5V below V EE or 44V above V EE, independent of V CC. The LT636 op amp is available in the 8-pin MSOP, PDIP and SO packages. For space limited applications the LT636 is available in a 3mm 3mm.8mm dual fine pitch leadless package (DFN). Over-The-Top is a registered trademark of Linear Technology Corporation., LTC and LT are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATIO SHDN Over-The-Top Current Source with Shutdown R* + LT636 LT4-.2 M I OT *OPTIONAL FOR LOW OTPT CRRENTS R TPO6 4V TO 44V I OT =.2 R e.g., ma = 2Ω 636 TA INPT BIAS CRRENT (na) Input Bias Current vs Common Mode Voltage V S = 5V, V T A = 55 C T A = 25 C T A = 25 C COMMON MODE VOLTAGE (V) 636 G3

2 LT636 ABSOLTE MAXIMM RATINGS W W W Total Supply Voltage (V + to V )... 44V Input Differential Voltage... 44V Input Current... ±25mA Shutdown Pin Voltage Above V... 32V Shutdown Pin Current... ±ma Output Short-Circuit Duration (Note 2)...Continuous Operating Temperature Range (Note 3) LT636C/LT636I... 4 C to 85 C LT636H... 4 C to 25 C (Note ) Specified Temperature Range (Note 4) LT636C/LT636I... 4 C to 85 C LT636H... 4 C to 25 C Junction Temperature... 5 C Junction Temperature (DD Package) C Storage Temperature Range C to 5 C Storage Temperature Range (DD Package) C to 25 C Lead Temperature (Soldering, sec)... 3 C PACKAGE/ORDER I FOR ATIO W TOP VIEW TOP VIEW NLL IN +IN V DD PACKAGE 8-LEAD (3mm 3mm) PLASTIC DFN T JMAX = 25 C, θ JA = 6 C/W (NOTE 2) NDERSIDE METAL CONNECTED TO V ORDER PART NMBER LT636CDD LT636IDD NLL V + OT SHDN DD PART* MARKING LAAJ NLL IN 2 +IN 3 V 4 ORDER PART NMBER LT636CMS8 LT636IMS8 TOP VIEW 8 NLL 7 V + 6 OT 5 SHDN MS8 PACKAGE 8-LEAD PLASTIC MSOP T JMAX = 5 C, θ JA = 25 C/W MS8 PART* MARKING LTCL T JMAX = 5 C, θ JA = 5 C/W (N8) T JMAX = 5 C, θ JA = 9 C/W (S8) ORDER PART NMBER LT636CN8 LT636CS8 LT636IN8 LT636IS8 LT636HS8 S8 PART* MARKING I 636H *The temperature grades are identified by a label on the shipping container. Consult factory for parts specified with wider operating temperature ranges. NLL IN +IN V N8 PACKAGE 8-LEAD PDIP NLL V + OT SHDN S8 PACKAGE 8-LEAD PLASTIC SO 3V A D 5V ELECTRICAL CHARACTERISTICS The denotes the specifications which apply over the full operating temperature range of 4 C T A 85 C. V S = 3V, V; V S = 5V, V; V CM = V OT = half supply unless otherwise specified. (Note 4) LT636C/LT636I SYMBOL PARAMETER CONDITIONS MIN TYP MAX NITS V OS Input Offset Voltage N8 Package µv C T A 7 C 4 µv 4 C T A 85 C 55 µv S8 Package µv C T A 7 C 6 µv 4 C T A 85 C 75 µv MS8 Package µv C T A 7 C 7 µv 4 C T A 85 C 5 µv 2

3 3V A D 5V ELECTRICAL CHARACTERISTICS The denotes the specifications which apply over the full operating temperature range of 4 C T A 85 C. V S = 3V, V; V S = 5V, V; V CM = V OT = half supply unless otherwise specified. (Note 4) LT636 LT636C/LT636I SYMBOL PARAMETER CONDITIONS MIN TYP MAX NITS DD Package µv C T A 7 C 9 µv 4 C T A 85 C 5 µv Input Offset Voltage Drift (Note 9) N8 Package, 4 C T A 85 C 5 µv/ C S8 Package, 4 C T A 85 C 2 8 µv/ C MS8 Package, 4 C T A 85 C 2 µv/ C DD Package, 4 C T A 85 C 2 µv/ C I OS Input Offset Current..8 na V CM = 44V (Note 5).6 µa I B Input Bias Current 5 8 na V CM = 44V (Note 5) 3 6 µa V S = V. na Input Noise Voltage.Hz to Hz.7 µv P-P e n Input Noise Voltage Density f = khz 52 nv/ Hz i n Input Noise Current Density f = khz.35 pa/ Hz R IN Input Resistance Differential 6 MΩ Common Mode, V CM = V to 44V 7 5 MΩ C IN Input Capacitance 4 pf Input Voltage Range 44 V CMRR Common Mode Rejection Ratio V CM = V to V CC V 84 db (Note 5) V CM = V to 44V (Note 8) db A VOL Large-Signal Voltage Gain V S = 3V, V O = 5mV to 2.5V, R L = k 2 3 V/mV V S = 3V, C T A 7 C 33 V/mV V S = 3V, 4 C T A 85 C V/mV V S = 5V, V O = 5mV to 4.5V, R L = k 4 2 V/mV V S = 5V, C T A 7 C 25 V/mV V S = 5V, 4 C T A 85 C 2 V/mV V OL Output Voltage Swing LOW No Load 2 mv I SINK = 5mA mv V S = 5V, I SINK = ma 86 6 mv V OH Output Voltage Swing HIGH V S = 3V, No Load V V S = 3V, I SORCE = 5mA V V S = 5V, No Load V V S = 5V, I SORCE = ma V I SC Short-Circuit Current (Note 2) V S = 3V, Short to GND 7 5 ma V S = 3V, Short to V CC 2 42 ma V S = 5V, Short to GND 2 25 ma V S = 5V, Short to V CC 25 5 ma PSRR Power Supply Rejection Ratio V S = 2.7V to 2.5V, V CM = V O = V 9 3 db Reverse Supply Voltage I S = µa 27 4 V I S Supply Current (Note 6) µa 6 µa Supply Current, SHDN V PIN5 = 2V, No Load (Note 6) 4 2 µa I SD Shutdown Pin Current V PIN5 =.3V, No Load (Note 6).5 5 na V PIN5 = 2V, No Load (Note 5). 5 µa Output Leakage Current, SHDN V PIN5 = 2V, No Load (Note 6).5 µa Maximum Shutdown Pin Current V PIN5 = 32V, No Load (Note 5) 27 5 µa t ON Turn-On Time V PIN5 = 5V to V, R L = k 2 µs t OFF Turn-Off Time V PIN5 = V to 5V, R L = k 2.5 µs 3

4 LT636 3V A D 5V ELECTRICAL CHARACTERISTICS The denotes the specifications which apply over the full operating temperature range of 4 C T A 85 C. V S = 3V, V; V S = 5V, V; V CM = V OT = half supply unless otherwise specified. (Note 4) LT636C/LT636I SYMBOL PARAMETER CONDITIONS MIN TYP MAX NITS GBW Gain Bandwidth Product f = khz 2 khz (Note 5) C T A 7 C khz 4 C T A 85 C 9 khz SR Slew Rate A V =, R L =.35.7 V/µs (Note 7) C T A 7 C.3 V/µs 4 C T A 85 C.3 V/µs ±5V ELECTRICAL CHARACTERISTICS The denotes the specifications which apply over the full operating temperature range of 4 C T A 85 C. V S = ±5V, V CM = V, V OT = V, V SHDN = V unless otherwise specified. (Note 4) LT636C/LT636I SYMBOL PARAMETER CONDITIONS MIN TYP MAX NITS V OS Input Offset Voltage N8 Package 45 µv C T A 7 C 55 µv 4 C T A 85 C 7 µv 4 S8 Package 45 µv C T A 7 C 75 µv 4 C T A 85 C 9 µv MS8 Package 45 µv C T A 7 C 85 µv 4 C T A 85 C 2 µv DD Package µv C T A 7 C 5 µv 4 C T A 85 C 2 µv Input Offset Voltage Drift (Note 9) N8 Package, 4 C T A 85 C 4 µv/ C S8 Package, 4 C T A 85 C 2 8 µv/ C MS8 Package, 4 C T A 85 C 2 µv/ C DD Package, 4 C T A 85 C 2 µv/ C I OS Input Offset Current.2. na I B Input Bias Current 4 na Input Noise Voltage.Hz to Hz µv P-P e n Input Noise Voltage Density f = khz 52 nv/ Hz i n Input Noise Current Density f = khz.35 pa/ Hz R IN Input Resistance Differential MΩ Common Mode, V CM = 5V to 4V 2 MΩ C IN Input Capacitance 4 pf Input Voltage Range 5 29 V CMRR Common Mode Rejection Ratio V CM = 5V to 29V 86 3 db A VOL Large-Signal Voltage Gain V O = ±4V, R L = k 5 V/mV C T A 7 C 75 V/mV 4 C T A 85 C 5 V/mV V OL Output Voltage Swing LOW No Load V I SINK = 5mA V I SINK = ma V V OH Output Voltage Swing HIGH No Load V I SORCE = 5mA V I SORCE = ma V

5 ±5V ELECTRICAL CHARACTERISTICS The denotes the specifications which apply over the full operating temperature range of 4 C T A 85 C, otherwise specifications are at T A = 25 C. V S = ±5V, V CM = V, V OT = V, V SHDN = V unless otherwise specified. (Note 4) LT636 LT636C/LT636I SYMBOL PARAMETER CONDITIONS MIN TYP MAX NITS I SC Short-Circuit Current (Note 2) Short to GND ±8 ±3 ma C T A 7 C ±5 ma 4 C T A 85 C ± ma PSRR Power Supply Rejection Ratio V S = ±.35V to ±22V 9 4 db I S Supply Current 5 7 µa 85 µa Positive Supply Current, SHDN V PIN5 = 2V, V S = ±22V, No Load 2 3 µa I SHDN Shutdown Pin Current V PIN5 = 2.7V, V S = ±22V, No Load.7 5 na V PIN5 = 2V, V S = ±22V, No Load.2 8 µa Maximum Shutdown Pin Current V PIN5 = 32V, V S = ±22V 27 5 µa Output Leakage Current, SHDN V PIN5 = 2V, V S = ±22V, No Load. 2 µa GBW Gain Bandwidth Product f = khz khz C T A 7 C khz 4 C T A 85 C khz SR Slew Rate A V =, R L =, V O = ±V Measured at ±5V V/µs C T A 7 C.33 V/µs 4 C T A 85 C.3 V/µs 3V A D 5V ELECTRICAL CHARACTERISTICS The denotes the specifications which apply over the full operating temperature range of 4 C T A 25 C. V S = 3V, V; V S = 5V, V; V CM = V OT = half supply unless otherwise specified. (Note 4) LT636H SYMBOL PARAMETER CONDITIONS MIN TYP MAX NITS V OS Input Offset Voltage µv 3 mv Input Offset Voltage Drift (Note 9) 3 µv/ C I OS Input Offset Current 3 na V CM = 44V (Note 5) µa I B Input Bias Current 3 na V CM = 44V (Note 5) µa Input Voltage Range.3 44 V CMRR Common Mode Rejection Ratio V CM =.3V to V CC V 72 db (Note 5) V CM =.3V to 44V 74 db A VOL Large-Signal Voltage Gain V S = 3V, V O = 5mV to 2.5V, R L = k 2 3 V/mV 2 V/mV V S = 5V, V O = 5mV to 4.5V, R L = k 4 2 V/mV 35 V/mV V OL Output Voltage Swing LOW No Load 5 mv I SINK = 2.5mA 875 mv V OH Output Voltage Swing HIGH V S = 3V, No Load V V S = 3V, I SORCE = 5mA 2.35 V V S = 5V, No Load V V S = 5V, I SORCE = ma 4. V PSRR Power Supply Rejection Ratio V S = 2.7V to 2.5V, V CM = V O = V 8 db Minimum Supply Voltage 2.7 V 5

6 LT636 3V A D 5V ELECTRICAL CHARACTERISTICS The denotes the specifications which apply over the full operating temperature range of 4 C T A 25 C. V S = 3V, V; V S = 5V, V; V CM = V OT = half supply unless otherwise specified. (Note 4) LT636H SYMBOL PARAMETER CONDITIONS MIN TYP MAX NITS Reverse Supply Voltage I S = µa 25 V I S Supply Current (Note 6) µa 75 µa Supply Current, SHDN V PIN5 = 2V, No Load (Note 6) 5 µa I SD Shutdown Pin Current V PIN5 =.3V, No Load (Note 6) 2 na V PIN5 = 2V, No Load (Note 5) 7 µa Output Leakage Current, SHDN V PIN5 = 2V, No Load (Note 6) 5 µa Maximum Shutdown Pin Current V PIN5 = 32V, No Load (Note 5) 2 µa GBW Gain Bandwidth Product f = khz (Note 5) 2 khz 6 khz SR Slew Rate A V =, R L = (Note 7).35.7 V/µs.5 V/µs ±5V ELECTRICAL CHARACTERISTICS The denotes the specifications which apply over the full operating temperature range of 4 C T A 25 C. V S = ±5V, V CM = V, V OT = V, V SHDN = V unless otherwise specified. (Note 4) LT636H SYMBOL PARAMETER CONDITIONS MIN TYP MAX NITS V OS Input Offset Voltage 55 µv 3.4 mv Input Offset Voltage Drift (Note 9) 3 µv/ C I OS Input Offset Current 5 na I B Input Bias Current 5 na CMRR Common Mode Rejection Ratio V CM = 4.7V to 29V 72 db A VOL Large-Signal Voltage Gain V O = ±4V, R L = k 5 V/mV 4 V/mV V O Output Voltage Swing No Load ±4.8 V I OT = ±2.5mA ±4.3 V PSRR Power Supply Rejection Ratio V S = ±.35V to ±22V 84 db Minimum Supply Voltage ±.35 V I S Supply Current 5 7 µa µa Positive Supply Current, SHDN V PIN5 = 2V, V S = ±22V, No Load 4 µa I SHDN Shutdown Pin Current V PIN5 = 2.7V, V S = ±22V, No Load 2 na V PIN5 = 2V, V S = ±22V, No Load µa Maximum Shutdown Pin Current V PIN5 = 32V, V S = ±22V 2 µa Output Leakage Current, SHDN V PIN5 = 2V, V S = ±22V, No Load µa V L Shutdown Pin Input Low Voltage V S = ±22V 2.7 V V H Shutdown Pin Input High Voltage V S = ±22V 2 V GBW Gain Bandwidth Product f = khz khz 75 khz SR Slew Rate A V =, R L =, V O = ±V V/µs Measured at V O = ±5V.2 V/µs 6

7 ELECTRICAL CHARACTERISTICS Note : Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: A heat sink may be required to keep the junction temperature below absolute maximum. The θ JA specified for the DD package is with minimal PCB heat spreading metal. A significant reduction in θ JA can be obtained with expanded PCB metal area on all layers of a board. Note 3: The LT636C and LT636I are guaranteed functional over the operating temperature range of 4 C to 85 C. The LT636H is guaranteed functional over the operating temperature range of 4 C to 25 C. Note 4: The LT636C is guaranteed to meet specified performance from C to 7 C. The LT636C is designed, characterized and expected to meet specified performance from 4 C to 85 C but is not tested or QA LT636 sampled at these temperatures. The LT636I is guaranteed to meet specified performance from 4 C to 85 C. The LT636H is guaranteed to meet specified performance from 4 C to 25 C. Note 5: V S = 5V limits are guaranteed by correlation to V S = 3V and V S = ±5V or V S = ±22V tests. Note 6: V S = 3V limits are guaranteed by correlation to V S = 5V and V S = ±5V or V S = ±22V tests. Note 7: Guaranteed by correlation to slew rate at V S = ±5V and GBW at V S = 3V and V S = ±5V tests. Note 8: This specification implies a typical input offset voltage of 6µV at V CM = 44V and a maximum input offset voltage of 3mV at V CM = 44V. Note 9: This parameter is not % tested. TYPICAL PERFOR A CE CHARACTERISTICS W SPPLY CRRENT (µa) Supply Current vs Supply Voltage T A = 25 C 5 4 T A = 55 C T A = 25 C TOTAL SPPLY VOLTAGE (V) CHANGE IN INPT OFFSET VOLTAGE (µv) Minimum Supply Voltage 3 2 T A = 25 C 2 T A = 55 C T A = 25 C TOTAL SPPLY VOLTAGE (V) 5 INPT BIAS CRRENT (na) Input Bias Current vs Common Mode Voltage V S = 5V, V T A = 55 C T A = 25 C T A = 25 C COMMON MODE VOLTAGE (V) 636 G 636 G2 636 G3 OTPT SATRATION VOLTAGE (V). Output Saturation Voltage vs Load Current (Output High) V S = 5V V OD = 3mV T A = 25 C T A = 25 C T A = 55 C..... SORCING LOAD CRRENT (ma) 636 G4 OTPT SATRATION VOLTAGE (V).. Output Saturation Voltage vs Load Current (Output Low) V S = 5V V OD = 3mV T A = 25 C T A = 25 C T A = 55 C..... SINKING LOAD CRRENT (ma) 636 G5 OTPT SATRATION VOLTAGE (mv) Output Saturation Voltage vs Input Overdrive V S = ±2.5V NO LOAD OTPT HIGH OTPT LOW INPT OVERDRIVE (mv) 636 G6 7

8 LT636 TYPICAL PERFOR A CE CHARACTERISTICS W NOISE VOLTAGE (4nV/DIV).Hz to Hz Noise Voltage V S = ±2.5V TIME (SEC) INPT NOISE VOLTAGE DENSITY (nv/ Hz) Noise Voltage Density vs Frequency FREQENCY (Hz) INPT NOISE CRRENT DENSITY (pa/ Hz) Input Noise Current vs Frequency FREQENCY (Hz) 636 G7 636 G8 635 G9 GAIN (db) k Open-Loop Gain and Phase Shift vs Frequency GAIN PHASE k k M FREQENCY (Hz) V S = ±2.5V 636 G PHASE SHIFT (DEG) GAIN-BANDWIDTH PRODCT (khz) Gain-Bandwidth Product vs Temperature f = khz V S = ±.5V V S = ±5V TEMPERATRE ( C) 636 G SLEW RATE (V/µs) Slew Rate vs Temperature RISING, V S = ±.5V RISING, V S = ±5V FALLING, V S = ±5V FALLING, V S = ±.5V TEMPERATRE ( C) 636 G2 GAIN-BANDWIDTH PRODCT (khz) Gain-Bandwidth Product and Phase Margin vs Supply Voltage R L = k f = khz PHASE MARGIN GAIN BANDWIDTH PHASE MARGIN (DEG) COMMON MODE REJECTION RATIO (db) CMRR vs Frequency V S = ±.5V V S = ±5V POWER SPPLY REJECTION RATIO (db) PSRR vs Frequency V S = ±2.5V NEGATIVE SPPLY POSITIVE SPPLY TOTAL SPPLY VOLTAGE (V) 2 K K FREQENCY (Hz) K 2 k k FREQENCY (Hz) k 636 G3 636 G4 636 G5 8

9 LT636 TYPICAL PERFOR A CE CHARACTERISTICS W GAIN-BANDWIDTH PRODCT (khz) Gain-Bandwidth Product and Phase Margin vs Load Resistance V S = ±2.5V GAIN BANDWIDTH PHASE MARGIN PHASE MARGIN (DEG) OTPT IMPEDANCE (Ω) Output Impedance vs Frequency k V S = ±2.5V k A V = A V = A V = OTPT SWING (V P-P ) ndistorted Output Swing vs Frequency V s = ±5V V s = ±2.5V DISTORTION % A V = 5 k k LOAD RESISTANCE (Ω) k. k k FREQENCY (Hz) k k k k FREQENCY (Hz) 636 G6 635 G7 635 G8 OTPT STEP (V) Settling Time to.% vs Output Step V S = ±5V A V = A V = A V = A V = SETTLING TIME (µs) 636 G9 OVERSHOOT (%) Capacitive Load Handling, Overshoot vs Capacitive Load V S = ±2.5V I SORCE = 4µA NO OTPT COMPENSATION A V = A V = 5 A V = 2 A V = CAPACITIVE LOAD (pf) 636 G2 THD + NOISE (%)... Total Harmonic Distortion + Noise vs Frequency V S = 3V, V V OT = 2V P-P V CM =.2V R L = 5k A V = A V = k k FREQENCY (Hz) 636 G2 THD + NOISE (%)... Total Harmonic Distortion + Noise vs Load Resistance V S = 3V, V V IN =.5V TO 2.5V V S = 3V TOTAL A V = V IN = 2V P-P AT khz V S = ±.5V V IN = ±V V S = 3V, V V IN =.2V TO 2.2V k k k LOAD RESISTANCE TO GROND (Ω) 636 G22 THD + NOISE (%).. Total Harmonic Distortion + Noise vs Output Voltage R L = k V CM = HALF SPPLY f = khz A V = V S = ±.5V A V = V S = ±.5V A V = V S = 3V, V A V = V S = 3V, V. 2 3 OTPT VOLTAGE (V P-P ) 636 G23 9

10 LT636 TYPICAL PERFOR A CE CHARACTERISTICS W Open-Loop Gain Large-Signal Response Small-Signal Response CHANGE IN INPT OFFSET VOLTAGE (µv/div) A C B A B C A: R L = 2k B: R L = k C: R L = 5k V S = ±5V V V V OTPT VOLTAGE (5V/DIV) 636 G24 V S = ±5V A V = 636 G25 V S = ±5V A V = 636 G26 APPLICATIONS INFORMATION Supply Voltage W The positive supply pin of the LT636 should be bypassed with a small capacitor (about.µf) within an inch of the pin. When driving heavy loads an additional 4.7µF electrolytic capacitor should be used. When using split supplies, the same is true for the negative supply pin. The LT636 is protected against reverse battery voltages up to 27V. In the event a reverse battery condition occurs, the supply current is less than na. When operating the LT636 on total supplies of 2V or more, the supply must not be brought up faster than µs. This is especially true if low ESR bypass capacitors are used. A series RLC circuit is formed from the supply lead inductance and the bypass capacitor. 5Ω of resistance in the supply or the bypass capacitor will dampen the tuned circuit enough to limit the rise time. Inputs The LT636 has two input stages, NPN and PNP (see Simplified Schematic), resulting in three distinct operating regions as shown in the Input Bias Current vs Common Mode typical performance curve. For input voltages about.8v or more below V +, the PNP input stage is active and the input bias current is typically 4nA. When the input voltage is about.5v or less from V +, the NPN input stage is operating and the input bias current is typically na. Increases in temperature will cause the voltage at which operation switches from the PNP stage to the NPN stage to move towards V +. The input offset voltage of the NPN stage is untrimmed and is typically 6µV. A Schottky diode in the collector of each NPN transistor of the NPN input stage allows the LT636 to operate with either or both of its inputs above V +. At about.3v above V + the NPN input transistor is fully saturated and the input bias current is typically 3µA at room temperature. The input offset voltage is typically 6µV when operating above V +. The LT636 will operate with its input 44V above V regardless of V +. The inputs are protected against excursions as much as 22V below V by an internal k resistor in series with each input and a diode from the input to the negative supply. There is no output phase reversal for inputs up to 5V below V. There are no clamping diodes between the inputs and the maximum differential input voltage is 44V. Output The output voltage swing of the LT636 is affected by input overdrive as shown in the typical performance curves. When monitoring voltages within mv of V +, gain should be taken to keep the output from clipping. The output of the LT636 can be pulled up to 27V beyond V + with less than na of leakage current, provided that V + is less than.5v.

11 LT636 APPLICATIONS INFORMATION W The normally reverse biased substrate diode from the output to V will cause unlimited currents to flow when the output is forced below V. If the current is transient and limited to ma, no damage will occur. The LT636 is internally compensated to drive at least 2pF of capacitance under any output loading conditions. A.22µF capacitor in series with a 5Ω resistor between the output and ground will compensate these amplifiers for larger capacitive loads, up to,pf, at all output currents. Distortion There are two main contributors of distortion in op amps: output crossover distortion as the output transitions from sourcing to sinking current and distortion caused by nonlinear common mode rejection. Of course, if the op amp is operating inverting there is no common mode induced distortion. When the LT636 switches between input stages there is significant nonlinearity in the CMRR. Lower load resistance increases the output crossover distortion, but has no effect on the input stage transition distortion. For lowest distortion the LT636 should be operated single supply, with the output always sourcing current and with the input voltage swing between ground and (V +.8V). See the Typical Performance Characteristics curves. Gain The open-loop gain is less sensitive to load resistance when the output is sourcing current. This optimizes performance in single supply applications where the load is returned to ground. The typical performance photo of Open-Loop Gain for various loads shows the details. Shutdown The LT636 can be shut down two ways: using the shutdown pin or bringing V + to within.5v of V. When V + is brought to within.5v of V both the supply current and output leakage current drop to less than na. When the shutdown pin is brought.2v above V, the supply current drops to about 4µA and the output leakage current is less than µa, independent of V +. In either case the input bias current is less than.na (even if the inputs are 44V above the negative supply). The shutdown pin can be taken up to 32V above V. The shutdown pin can be driven below V, however the pin current through the substrate diode should be limited with an external resistor to less than ma. Input Offset Nulling The input offset voltage can be nulled by placing a k potentiometer between Pins and 8 with its wiper to V (see Figure ). The null range will be at least ±mv. LT636 k V 636 F Figure. Input Offset Nulling 8

12 LT636 TYPICAL APPLICATIONS MX Amplifier MX Amplifier Waveforms V IN + LT636 SHDN 5V VOT V IN2 + 5V LT636 SHDN V S = 5V V IN =.2kHz AT 4V P-P, V IN2 = 2.4kHz AT 2V P-P INPT SELECT = 2Hz AT 5V P-P INPT SELECT 74HC4 636 TA5 Optional Output Compensation for Capacitive Loads Greater Than 2pF V IN + LT636 C L,pF.22µF 5Ω 636 TA9 2

13 LT636 W SI PLIFIED SCHEMATIC W Q D D2 Q3 Q9 7 V + Q25 SHDN 5 R M Q3 2µA R2 3k Q2 IN +IN 2 3 R3 k R4 k Q Q9 Q Q2 Q4 Q5 Q6 Q7 Q8 D3 Q2 Q2 Q22 Q23 Q24 6 OT Q26 Q4 Q5 Q6 Q7 Q8 D4 D5 NLL R5 R6 4k 4k 8 NLL R7 3Ω R8 3Ω 636 SS 4 V 3

14 LT636 PACKAGE DESCRIPTION DD Package 8-Lead Plastic DFN (3mm 3mm) (Reference LTC DWG # ).675 ±.5 R =.5 TYP ±. 3.5 ± ±.5.65 ±.5 (2 SIDES) PACKAGE OTLINE.28 ±.5.5 BSC 2.38 ±.5 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS PIN TOP MARK.2 REF 3. ±. (4 SIDES).75 ± ±. (2 SIDES) 4.28 ± ±. (2 SIDES) BOTTOM VIEW EXPOSED PAD NOTE:. DRAWING TO BE MADE A JEDEC PACKAGE OTLINE M-229 VARIATION OF (WEED-) 2. ALL DIMENSIONS ARE IN MILLIMETERS 3. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED.5mm ON ANY SIDE 4. EXPOSED PAD SHALL BE SOLDER PLATED.5 BSC (DD8) DFN 23 MS8 Package 8-Lead Plastic MSOP (Reference LTC DWG # ).889 ±.27 (.35 ±.5) 5.23 (.26) MIN (.26.36) 4.42 ±.4 (.65 ±.5) TYP GAGE PLANE.8 (.77).254 (.) DETAIL A.65 (.256) BSC RECOMMENDED SOLDER PAD LAYOT DETAIL A NOTE:. DIMENSIONS IN MILLIMETER/(INCH) 2. DRAWING NOT TO SCALE 6 TYP.53 ±.5 (.2 ±.6) SEATING PLANE 3. ±.2 (.8 ±.4) (NOTE 3) 4.9 ±.5 (.93 ±.6). (.43) MAX (.9.5) TYP.65 (.256) BSC DIMENSION DOES NOT INCLDE MOLD FLASH, PROTRSIONS OR GATE BRRS. MOLD FLASH, PROTRSIONS OR GATE BRRS SHALL NOT EXCEED.52mm (.6") PER SIDE 4. DIMENSION DOES NOT INCLDE INTERLEAD FLASH OR PROTRSIONS. INTERLEAD FLASH OR PROTRSIONS SHALL NOT EXCEED.52mm (.6") PER SIDE 5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE.2mm (.4") MAX.52 (.26) REF 3. ±.2 (.8 ±.4) NOTE 4.86 (.34) REF.3 ±.76 (.5 ±.3) MSOP (MS8) 82

15 LT636 PACKAGE DESCRIPTION N8 Package 8-Lead PDIP (Narrow.3 Inch) (Reference LTC DWG # 5-8-5).4* (.6) MAX ±.5* (6.477 ±.38) ( ) (.43.65).3 ±.5 (3.32 ±.27).8.5 (.23.38) ( ).65 (.65) TYP. (2.54) BSC NOTE: INCHES. DIMENSIONS ARE MILLIMETERS *THESE DIMENSIONS DO NOT INCLDE MOLD FLASH OR PROTRSIONS. MOLD FLASH OR PROTRSIONS SHALL NOT EXCEED. INCH (.254mm).2 (3.48) MIN.8 ±.3 (.457 ±.76).2 (.58) MIN N8 2 S8 Package 8-Lead Plastic Small Outline (Narrow.5 Inch) (Reference LTC DWG # 5-8-6) N.5 BSC.45 ± ( ) NOTE MIN 2 3 N/2.6 ± ( ) N N/ ( ) NOTE 3.3 ±.5 TYP RECOMMENDED SOLDER PAD LAYOT ( )..2 ( ) 45 8 TYP ( ).4. (..254) (.46.27) ( ) NOTE: INCHES TYP. DIMENSIONS IN (MILLIMETERS) 2. DRAWING NOT TO SCALE 3. THESE DIMENSIONS DO NOT INCLDE MOLD FLASH OR PROTRSIONS. MOLD FLASH OR PROTRSIONS SHALL NOT EXCEED.6" (.5mm).5 (.27) BSC Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. SO8 52 5

16 LT636 TYPICAL APPLICATIONS Over-The-Top Comparator with Hysteresis M 3V TO 44V Self-Buffered Micropower Reference 4V TO 44V IN (V TO 44V) IN2 (V TO 44V) k k HYSTERESIS = + V CC LT636 M 2N587 2N TA3 M M V OT.µF LT636 + M LT V OT =.25V I OT ma N TA4 Lamp Outage Detector Over-The-Top Current Sense LAMP ON/OFF 5V TO 44V k 5k.5Ω M 3V LT636 + OT OT = V FOR GOOD BLB 3V FOR OPEN BLB 5V TO 44V R 2Ω LOAD R S.2Ω I LOAD + 5V LT636 V I OT LOAD = (R S )(R2/R) R2 2k 636 TA8 V OT (V TO 4.3V) 636 TA7 RELATED PARTS PART NMBER DESCRIPTION COMMENTS LT78/LT79 Dual/Quad 55µA Max, Single Supply, Precision Op Amps Input/Output Common Mode Includes Ground, 7µV V OS(MAX) LT278/LT279 and 2.5µV/ C Drift (Max), 2kHz GBW,.7V/µs Slew Rate LT78/LT79 Dual/Quad 7µA Max, Single Supply, Precison Op Amps Input/Output Common Mode Includes Ground, 7µV V OS(MAX) LT278/LT279 and 4µV/ C Drift (Max), 85kHz GBW,.4V/µs Slew Rate LT366/LT367 Dual/Quad Precision, Rail-to-Rail Input and Output Op Amps 475µV V OS(MAX), 5V/mV A VOL(MIN), 4kHz GBW LT49/LT49 Dual/Quad Over-The-Top Micropower, Rail-to-Rail Input and Single Supply Input Range:.4V to 44V, Micropower 5µA Output Op Amps per Amplifier, Rail-to-Rail Input and Output, 2kHz GBW LT637 Single Over-The-Top Micropower Rail-to-Rail Input and Output.MHz, V CM Extends 44V above V EE, Op Amp Independent of V CC ; MSOP Package, Shutdown Function LT638/LT639 Dual/Quad.2MHz Over-The-Top Micropower, Rail-to-Rail.4V/µs Slew Rate, 23µA Supply Current per Amplifier Input and Output Op Amps LT782 Micropower, Over-The-Top, SOT-23, Rail-to-Rail SOT-23, 8µV V OS(MAX), I S = 55µA (Max), Input and Output Op Amp Gain-Bandwidth = 2kHz, Shutdown Pin LT783.2MHz, Over-The-Top, Micropower, Rail-to-Rail SOT-23, 8µV V OS(MAX), I S = 3µA (Max), Input and Output Op Amp Gain-Bandwidth =.2MHz, Shutdown Pin 6 Linear Technology Corporation 63 McCarthy Blvd., Milpitas, CA (48) FAX: (48) LT/LT 55 REV C PRINTED IN SA LINEAR TECHNOLOGY CORPORATION 998