AS1976

AS1976, AS1977 U l t r a - L o w C u r r e n t , 1 . 8 V C o m pa r a t o r s D a ta S he e t 1 General Description The AS1976/AS1977 are very low-current comparators that can operate beyond the rail voltages and are guaranteed to operate down to 1.8V Low input bias current, current-limiting output circuitry, and ultra-small packaging make these comparators ideal for low-power 2-cell applications including powermanagement and power-monitoring systems. The comparators are available as the standard products listed in Table 1. Table 1. Standard Products 2 Key Features ! CMOS Push/Pull Output Sinks and Sources 8mA (AS1976) CMOS Open-Drain Output Voltage Extends Beyond VCC (AS1977) Ultra-Low Supply Current: 200nA Internal Hysteresis: 3mV 3V-to5V Logiv-Level Translation Guaranteed to Operate Down to +1.8V Input Voltage Range Operates 200mV Beyond the Rails Crowbar Current-Free Switching No Phase Reversal for Overdriven Inputs 5-pin SOT23 Package ! ! ! ! Model AS1976 AS1977 Output Type Push/Pull Open-Drain Current 200nA 200nA ! ! The AS1976 push/pull output can sink or source current. The AS1977 open-drain output can be pulled beyond VCC to a maximum of 6V > VEE. This open-drain model is ideal for use as a logic-level translator or bipolar-tounipolar converter. Large internal output drivers provide rail-to-rail output swings with loads up to 8mA. Both devices feature builtin battery power-management and power-monitoring circuitry. The AS1976/AS1977 are available in a 5-pin SOT23 package. ! ! ! 3 Applications The devices are ideal for battery monitoring/management, mobile communication devices, laptops and PDAs, ultra-low-power systems, threshold detectors/discriminators, telemetry and remote systems, medical instruments, or any other space-limited application with low power-consumption requirements. Figure 1. Block Diagram 5 VCC AS1976/ AS1977 + – 1 OUT 3 IN+ 4 IN2 VEE www.austriamicrosystems.com Revision 1.01 1 - 17 AS1976/AS1977 Data Sheet - P i n o u t 4 Pinout Pin Assignments Figure 2. Pin Assignments (Top View) OUT 1 5 VCC VEE 2 AS1976/ AS1977 IN+ 3 4 IN- Pin Descriptions Table 2. Pin Descriptions Pin Number 1 2 3 4 5 Pin Name OUT VEE IN+ INVCC Comparator Output Negative Supply Voltage Comparator Non-Inverting Input Comparator Inverting Input Positive Supply Voltage Description www.austriamicrosystems.com Revision 1.01 2 - 17 AS1976/AS1977 Data Sheet - A b s o l u t e M a x i m u m R a t i n g s 5 Absolute Maximum Ratings Stresses beyond those listed in Table 3 may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in Section 6 Electrical Characteristics on page 4 is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Table 3. Absolute Maximum Ratings Parameter Supply Voltage VCC to VEE Voltage Inputs IN+, INOutput Voltage AS1976, AS1978 Output Current Output Short-Circuit Duration Continuous Power Dissipation Operating Temperature Range Storage Temperature Range -40 -65 VEE - 0.3 VEE - 0.3 -50 Min Max +7 VCC + 0.3 VCC + 0.3 +50 10 571 +85 +150 Units V V V mA s mW ºC ºC The reflow peak soldering temperature (body temperature) specified is in accordance with IPC/ JEDEC J-STD-020C “Moisture/Reflow Sensitivity Classification for Non-Hermetic Solid State Surface Mount Devices”. The lead finish for Pb-free leaded packages is matte tin (100% Sn). Derate at 7.31mW/ºC above +70ºC Comments Package Body Temperature +260 ºC www.austriamicrosystems.com Revision 1.01 3 - 17 AS1976/AS1977 Data Sheet - E l e c t r i c a l C h a r a c t e r i s t i c s 6 Electrical Characteristics VCC = +5V, VEE = 0, VCM = 0, TAMB = -40 to +85ºC (unless otherwise specified). Typ values are at TAMB = +25ºC. Table 4. AS1976/AS1977 Electrical Characteristics Symbol VCC ICC Parameter Supply Voltage Range Supply Current Input Common-Mode Voltage Range Conditions Inferred from the PSRR test VCC = 1.8V VCC = 5V, TAMB = +25ºC VCC = 5V, TAMB = TMIN to TMAX VCM Inferred from CMRR test -0.2V ≤ VCM ≤ (VCC + 0.2V), 1 TAMB = +25ºC -0.2V ≤ VCM ≤ (VCC + 0.2V), TAMB = TMIN to TMAX -0.2V ≤ VCM ≤ (VCC + 0.2V) 3 2 Min 1.8 Typ 0.2 0.21 Max 5.5 0.5 0.9 VCC + 0.2 Units V µA VEE - 0.2 1 V 5 mV 10 VOS Input Offset Voltage VHB IB IOS PSRR CMRR Input-Referred Hysteresis Input Bias Current 3 0.15 10 1 2 mV nA pA 1 3 500 650 mV mV/V mV/V TAMB = +25ºC TAMB = TMIN to TMAX Input Offset Current Power-Supply Rejection Ratio Common-Mode Rejection Ratio VCC = 1.8 to 5.5V, TAMB = +25ºC (VEE - 0.2V) ≤ VCM ≤ (VCC + 0.2V), TAMB = +25ºC TAMB = +25ºC, AS1976 only VCC = 5.5V, ISINK = 8mA Output Voltage Swing High TAMB = TMIN to TMAX, AS1976 only VCC = 5.5V, ISINK = 8mA TAMB = +25ºC AS1976 only VCC = 1.8V, ISOURCE = 1mA TAMB = TMIN to TMAX, AS1976 only VCC = 1.8V, ISOURCE = 1mA TAMB = +25ºC, AS1976 only VCC = 5.5V, ISINK = 8mA Output Voltage Swing Low TAMB = TMIN to TMAX, AS1976 only VCC = 5.5V, ISINK = 8mA TAMB = +25ºC, VCC = 1.8V, ISOURCE = 1mA TAMB = TMIN to TMAX, VCC = 1.8V, ISOURCE = 1mA 0.05 0.2 220 VCC - VOH 80 200 300 220 500 650 mV VOL 70 200 300 ILEAK Output Leakage Current AS1977 only, VOUT = 5.5V Sourcing, VOUT = VEE, VCC = 5.5V 0.001 50 6 70 5 10 12 1 µA ISC Output Short-Circuit Current Sourcing, VOUT = VEE, VCC = 1.8V Sinking, VOUT = VCC, VCC = 5.5V Sinking, VOUT = VCC, VCC = 1.8V VCC = 1.8V VCC = 5.5V mA tPD- High-to-Low 4 Propagation Delay µs www.austriamicrosystems.com Revision 1.01 4 - 17 AS1976/AS1977 Data Sheet - E l e c t r i c a l C h a r a c t e r i s t i c s Table 4. AS1976/AS1977 Electrical Characteristics (Continued) Symbol Parameter Conditions AS1976 only, VCC = 1.8V tPD+ Low-to-High 4 Propagation Delay AS1976 only, VCC = 5.5V AS1977 only, VCC = 1.8V, RPULUP = 100kΩ AS1977 only, VCC = 3.6V, RPULUP = 100kΩ tRISE tFALL tON Rise Time Fall Time Power-Up Time AS1976 only, CLOAD = 15pF CLOAD = 15pF Min Typ 13 15 16 18 10 10 100 ns ns ns µs Max Units 1. VOS is defined as the center of the hysteresis band at the input. 2. The hysteresis-related trip points are defined as the edges of the hysteresis band, measured with respect to the center of the band (i.e., VOS) (see Figure 26 on page 11). 3. Guaranteed by design. 4. Specified with an input overdrive voltage (VOVERDRIVE) = 100mV, and load capacitance (CLOAD) = 15pF. VOVERDRIVE is defined above and beyond the offset voltage and hysteresis of the comparator input. A reference voltage error should also be added. www.austriamicrosystems.com Revision 1.01 5 - 17 AS1976/AS1977 Data Sheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s 7 Typical Operating Characteristics Figure 3. ICC vs. VCC and Temperature 500 Figure 4. ICC vs. Temperature 300 VCC = 3V Supply Current (nA) . Supply Current (nA) . 400 275 250 225 200 175 150 1.5 2.5 3.5 4.5 5.5 -40 -15 10 35 60 85 300 +85ºC +25ºC 200 -40ºC VCC = 5V VCC = 1.8V 100 0 Supply Voltage (V) Figure 5. ICC vs. Output Transition Frequency 50 Temperature (°C) Figure 6. VOL vs. ISINK 600 Supply Current (µA) . 40 VCC = 5V Output Voltage Low (mV) . 500 VCC = 3V 400 VCC = 1.8V 30 300 200 100 0 VCC = 5V 20 VCC = 3V VCC = 1.8V 10 0 1 10 100 1000 10000 100000 2 4 6 8 10 12 14 16 Output Transition Frequency (Hz) Figure 7. VOL vs. ISINK and Temperature 600 Sink Current (mA) Figure 8. VOH vs. ISOURCE 0.8 Output Voltage Low (mV) . 500 400 300 200 100 0 2 4 6 8 10 12 14 16 0 0 5 10 15 20 -40ºC +25ºC +85ºC VCC-VOH (mV) . 0.6 VCC = 1.8V VCC = 3V 0.4 VCC = 5V 0.2 Sink Current (mA) Source Current (mA) www.austriamicrosystems.com Revision 1.01 6 - 17 AS1976/AS1977 Data Sheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s Figure 9. VOH vs. ISOURCE and Temperature 0.8 Figure 10. Short Circuit Sink Current vs. Temperature 100 VCC-VOH (mV) . 0.6 +85ºC +25ºC Sink Current (mA) . 75 VCC = 5V 0.4 -40ºC 50 0.2 25 VCC = 3V VCC = 1.8V 0 0 5 10 15 20 0 -40 -15 10 35 60 85 Source Current (mA) Figure 11. Short Circuit Source Current vs. Temperature 80 Temperature (°C) Figure 12. tPD+ vs. Temperature 25 Source Current (mA) . 60 20 tPD+ (µs) . VCC = 5V 15 VCC = 5V VCC = 1.8V VCC = 3V 40 VCC = 3V 10 20 5 VCC = 1.8V 0 -40 -15 10 35 60 85 0 -40 -15 10 35 60 85 Temperature (°C) Figure 13. tPD- vs. Temperature 20 Temperature (°C) Figure 14. tPD- vs. Capacitive Load 150 125 16 VCC = 5V VCC = 3V tPD- (µs) . 100 12 VCC = 1.8V tPD- (µs) . 75 50 25 VCC = 5V VCC = 1.8V VCC = 3V 8 4 0 -40 -15 10 35 60 85 0 0.01 0.1 1 10 100 1000 Temperature (°C) Capacitive Load (nF) www.austriamicrosystems.com Revision 1.01 7 - 17 AS1976/AS1977 Data Sheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s Figure 15. tPD+ vs. Capacitive Load 200 Figure 16. tPD+ 5V 150 tPD+ (µs) . 100 VCC = 1.8V VCC = 3V VCC = 5V 0 0.01 0.1 1 10 100 1000 4µs/Div Capacitive Load (nF) Figure 17. tPD- 5V Figure 18. tPD+ 3V 100mV/Div 2V/Div 4µs/Div 4µs/Div Figure 19. tPD- 3V Figure 20. tPD+ 1.8V 100mV/Div 2V/Div 4µs/Div 4µs/Div www.austriamicrosystems.com Revision 1.01 1V/Div Out Out 100mV/Div In+ In+ 2V/Div Out Out 100mV/Div In+ In+ 2V/Div Out 50 100mV/Div In+ 8 - 17 AS1976/AS1977 Data Sheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s Figure 21. tPD- 1.8V Figure 22. 10kHz Response @ 1.8V 100mV/Div In+ 1V/Div 4µs/Div 20µs/Div Figure 23. 1kHz Response @ 5V Figure 24. Powerup/Powerdown Response 100mV/Div 2V/Div 200µs/Div 40µs/Div www.austriamicrosystems.com Revision 1.01 2V/Div Out Out 2V/Div In+ VCC 1V/Div Out Out 100mV/Div In+ 9 - 17 AS1976/AS1977 Data Sheet - D e t a i l e d D e s c r i p t i o n 8 Detailed Description The AS1976/AS1977 are ultra low-current comparators and are guaranteed to operate with voltages as low as +1.8V. The common-mode input voltage range extends 200mV beyond the rail voltages, and internal hysteresis ensures clean output switching, even with slow input signals. The AS1976 push/pull output stage sinks and sources-current. The AS1977 open-drain output stage can be pulled beyond VCC to an absolute maximum of 3.6V > VEE. The AS1979/AS1977 are perfect for implementing wired-OR output logic functions. For all comparators, large internal output drivers allow rail-to-rail output swings with loads of up to 8mA. The output stage design minimizes supply-current surges during switching, eliminating most power supply transients. Input Stage The input common-mode voltage range extends from (VEE - 0.2V) to (VCC + 0.2V), and the comparators can operate at any differential input voltage within this range. The comparators have very low input bias current (±0.15nA, typ) if the input voltage is within the common-mode voltage range. Inputs are protected from over-voltage conditions by internal ESD protection diodes connected to the supply rails. As the input voltage exceeds the supply rails, these ESD protection diodes are forward biased and begin to conduct. Output Stage The break-before-make output stage is capable of rail-to-rail operation with loads up to 8mA. Many comparators consume orders of magnitude more current during switching than during steady-state operation. Even at loads of up to 8mA, changes in supply-current during an output transition are extremely small (see Figure 5 on page 6). As shown in Figure 5, the minimal supply current increases as the output switching frequency approaches 1kHz. This characteristic reduces the need for power-supply filter capacitors to reduce transients created by comparator switching currents. Because of the unique design of its output stage, the AS1976/AS1977 can dramatically increase battery life, even in high-speed applications. www.austriamicrosystems.com Revision 1.01 10 - 17 AS1976/AS1977 Data Sheet - A p p l i c a t i o n I n f o r m a t i o n 9 Application Information The AS1976/AS1977 comparators are perfect for use with all 2-cell battery-powered applications. Figure 25 shows a typical application for the AS1977. Figure 25. AS1977 Typical Application Circuit VIN 5 4 INVCC AS1977 RPULLUP 1 OUT 3 IN+ 2 VEE Internal Hysteresis The comparators were designed with 3mV of internal hysteresis to neutralize the effects of parasitic feedback, i.e., to prevent unwanted rapid changes between the two output states. The internal hysteresis in the AS1976/AS1977 creates two trip points: ! ! Rising Input Voltage (VTHR) – The comparator switches its output from low to high as VIN rises above this trip point. Falling Input Voltage (VTHF) – The comparator switches its output from high to low as VIN falls below this trip point. The area between the trip points is the hysteresis band (VHB) (see Figure 26). When the AS1976/AS1977 input voltages are equivalent, the hysteresis effectively causes one input to move quickly past the other, thus taking the input out of the region where oscillation occurs. In Figure 26 IN- has a fixed voltage applied and IN+ is varied. Note: If the inputs are reversed the output will be inverted. Figure 26. Threshold Hysteresis Band Thresholds IN+ VTHR INVTHF VHB Hysteresis Band OUT www.austriamicrosystems.com Revision 1.01 11 - 17 AS1976/AS1977 Data Sheet - A p p l i c a t i o n I n f o r m a t i o n Additional Hysteresis (AS1976) Additional hysteresis can be added to the AS1976 and AS1978 with three resistors and positive feedback (see Figure 27), however, this positive feedback method slows hysteresis response time. Figure 27. AS1976 Additional Hysteresis VCC R3 R1 VIN + – VREF VCC VEE OUT R2 Resistor Selection Example For the circuit shown in Figure 27, use the following steps to calculate values for R1, R2, and R3. 1. First select the value for R3. Leakage current at IN is less than 2nA, thus the current through R3 should be at least 0.2µA to minimize errors due to leakage current. The current through R3 at the trip point is: (VREF - VOUT)/R3 (EQ 1) Taking into consideration the two possible output states, solving for R3 yields two formulas: R3 = VREF/IR3 R3 = (VCC - VREF)/IR3 (EQ 2) (EQ 3) Use the smaller of the two resulting values for R3. For example, for VREF = 1.245V, VCC = 3.3V, and IR3 = 1µA, the two resistor values are 1.2MΩ and 2.0MΩ, therefore choose a 1.2MΩ standard resistor for R3. 2. Choose the required hysteresis band (VHB). For this example, choose 33mV. 3. Calculate R1 as: R1 = R3(VHB/VCC) (EQ 4) Substituting the R1 and VHB example values gives: R1 = 1.2MΩ(50mV/3.3V) = 12kΩ 4. Choose the trip point for VIN rising (VTHR) such that VTHR > VREF(R1 + R3)/R3. For this example, choose 3V. 5. Calculate R2 as: R2 = 1/[VTHR/(VREF x R1) - (1/R1) - (1/R3)] (EQ 5) Substituting the R1 and R3 example values gives: R2 = 1/[3.0V/(1.2V x 12kΩ) - (1/12kΩ) - (1/1.2MΩ)] = 8.05kΩ In this example, a standard 8.2kΩ resistor should be used for R2. 6. Verify the trip voltages and hysteresis as: VTHR = VREF x R1[(1/R1) + (1/R2) + (1/R3)] VTHF = VTHR - (R1 x VCC/R3) Hysteresis = VTHR - VTHF (EQ 6) (EQ 7) (EQ 8) www.austriamicrosystems.com Revision 1.01 12 - 17 AS1976/AS1977 Data Sheet - A p p l i c a t i o n I n f o r m a t i o n Additional Hysteresis (AS1977) Additional hysteresis can be added to the AS1977 and AS1979 with 4 resistors and positive feedback (see Figure 28). Figure 28. AS1977 Additional Hysteresis VCC R3 R4 R1 VIN R2 VREF + – VCC VEE OUT Resistor Selection Example For the circuit shown in Figure 28, use the following steps to calculate values for R1, R2, R3, and R4. 1. Select R3 according to one of these formulas: R3 = VREF/1µA R3 = (VCC - VREF)/1µA - R4 (EQ 9) (EQ 10) Use the smaller of the two resulting resistor values for R3. 2. Choose the hysteresis band required (VHB). 3. Calculate R1 as: R1 = (R3 + R4)(VHB/VCC) (EQ 11) 4. Choose the trip point for VIN rising (VTHR). 5. Calculate R2 as: R2 = 1/[VTHR/(VREF x R1) - (1/R1) - 1/R3] (EQ 12) (EQ 13) (EQ 14) (EQ 15) 6. Verify the trip voltages and hysteresis as: VIN rising: VTHR = VREF[R1(1/R1 + 1/R2 + 1/R3)] VIN falling: VTHF = VREF[R1(1/R1 + 1/R2 + 1/(R3+R4))] - [1/(R3+R4)]VCC Hysteresis = VTHR - VTHF Zero-Crossing Detector Figure 29 shows the AS1976 in a zero-crossing detector circuit. The inverting input (IN-) is connected to ground, and the non-inverting input (IN+) is connected to a 100mVp-p signal source. When the signal at IN- crosses 0V, the signal at OUT changes states. Figure 29. Zero Crossing Detector 100mVp-p 3 IN+ 4 IN5 VCC + – 1 OUT AS1976 2 VEE www.austriamicrosystems.com Revision 1.01 13 - 17 AS1976/AS1977 Data Sheet - A p p l i c a t i o n I n f o r m a t i o n Logic-Level Translation The AS1977 can be used as a 5V-to-3V logic translator. Figure 30 shows an application that converts 5V- to 3V-logic levels, and provides the full 5V logic-swing without creating overvoltage on the 3V logic inputs. Note: When the comparator is powered by a 5V supply, RPULUP for the open-drain output should be connected to the +3V supply voltage. For 3V-to-5V logic-level translations, connect the +3V supply voltage to VCC and the +5V supply voltage to RPULUP. Figure 30. AS1977 Logic-Level Translation Circuit +3/+5V +3/+5V 100kΩ 5 VCC RPullup 4 REF 1 +5/+3V Logic Out 100kΩ AS1977 OUT +5/+3V Logic In 3 IN+ 2 VEE Logic-Level Translator Layout Considerations The AS1976/AS1977 requires proper layout and design techniques for optimum performance. ! ! ! ! Power-supply bypass capacitors are not typically required, although 100nF bypass capacitors should be placed close to the AS1976/AS1977 supply pins when supply impedance is high, leads are long, or for excessive noise on the supply lines. Minimize signal trace lengths to reduce stray capacitance. A ground plane should be used. Surface-mount components should be used whenever practical. www.austriamicrosystems.com Revision 1.01 14 - 17 AS1976/AS1977 Data Sheet - P a c k a g e D r a w i n g s a n d M a r k i n g s 10 Package Drawings and Markings The AS1976/AS1977 are available in a 5-pin SOT23 package. Figure 31. 5-pin SOT23 Package Symbol A A1 A2 b C D E E1 L e e1 α Min Max 0.90 1.45 0.00 0.15 0.90 1.30 0.30 0.50 0.09 0.20 2.80 3.05 2.60 3.00 1.50 1.75 0.30 0.55 0.95 REF 1.90 REF 0º 8º Notes: 1. 2. 3. 4. 5. Controlling dimension is millimeters. Foot length measured at intercept point between datum A and lead surface. Package outline exclusive of mold flash and metal burr. Package outline inclusive of solder plating. Meets JEDEC MO178. www.austriamicrosystems.com Revision 1.01 15 - 17 AS1976/AS1977 Data Sheet - O r d e r i n g I n f o r m a t i o n 11 Ordering Information The devices are available as the standard products shown in Table 5. Table 5. Ordering Information Type Marking Description Output Type Delivery Form Package AS1976 AS1976-T AS1977 AS1977-T ASI9 ASI9 ASJA ASJA Ultra-Low Current 1.8V Comparator Ultra-Low Current 1.8V Comparator Ultra-Low Current 1.8V Comparator Ultra-Low Current 1.8V Comparator Push/Pull Push/Pull Open-Drain Open-Drain Tube Tape and Reel Tube Tape and Reel 5-pin SOT23 5-pin SOT23 5-pin SOT23 5-pin SOT23 www.austriamicrosystems.com Revision 1.01 16 - 17 AS1976/AS1977 Data Sheet Copyrights Copyright © 1997-2007, austriamicrosystems AG, Schloss Premstaetten, 8141 Unterpremstaetten, Austria-Europe. Trademarks Registered ®. All rights reserved. The material herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. All products and companies mentioned are trademarks or registered trademarks of their respective companies. Disclaimer Devices sold by austriamicrosystems AG are covered by the warranty and patent indemnification provisions appearing in its Term of Sale. austriamicrosystems AG makes no warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described devices from patent infringement. austriamicrosystems AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior to designing this product into a system, it is necessary to check with austriamicrosystems AG for current information. This product is intended for use in normal commercial applications. Applications requiring extended temperature range, unusual environmental requirements, or high reliability applications, such as military, medical life-support or lifesustaining equipment are specifically not recommended without additional processing by austriamicrosystems AG for each application. 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Contact Information Headquarters austriamicrosystems AG A-8141 Schloss Premstaetten, Austria Tel: +43 (0) 3136 500 0 Fax: +43 (0) 3136 525 01 For Sales Offices, Distributors and Representatives, please visit: http://www.austriamicrosystems.com/contact www.austriamicrosystems.com Revision 1.01 17 - 17