TSM917 1.8V Nanopower Comparator with Internal 1.245V Reference FEATURES DESCRIPTION ♦ Second-source for MAX917 ♦ Guaranteed to Operate Down to +1.8V ♦ Ultra-Low Supply Current: 750nA ♦ Internal 1.245V ±1.5% Reference ♦ Input Voltage Range Extends 200mV Outside-the-Rails ♦ No Phase Reversal for Overdriven Inputs ♦ Push-pull Output ♦ Crowbar-Current-Free Switching ♦ Internal Hysteresis for Clean Switching ♦ 5-pin SOT23 and 8-pin SOIC Packaging The TSM917 nanopower analog comparator is electrically and form-factor identical to the MAX917 analog comparator. Ideally suited for all 2-cell batterymanagement/monitoring applications, this 5-pin SOT23 analog comparator guarantees +1.8V operation, draws very little supply current, and has a robust input stage that can tolerate input voltages beyond its power supply. The TSM917 draws 750nA of supply current and includes an on-board 1.245V ±1.5% reference. The TSM917’s push-push output drivers were designed to drive 8mA loads from one supply rail to the other supply rail. The TSM917 is also available in an 8-pin SOIC package. APPLICATIONS 2-Cell Battery Monitoring/Management Medical Instruments Threshold Detectors/Discriminators Sensing at Ground or Supply Line Ultra-Low-Power Systems Mobile Communications Telemetry and Remote Systems TYPICAL APPLICATION CIRCUIT The Touchstone Semiconductor logo is a registered trademark of Touchstone Semiconductor, Incorporated. Page 1 © 2011 Touchstone Semiconductor, Inc. All rights reserved. TSM917 ABSOLUTE MAXIMUM RATINGS Supply Voltage (VCC to VEE) ............................................ +6V Voltage Inputs (IN+, IN-, REF) .... (VEE - 0.3V) to (VCC + 0.3V) Output Voltage TSM917 ................................... (VEE - 0.3V) to (VCC + 0.3V) Current Into Input Pins ................................................ ±20mA Output Current ............................................................ ±50mA Output Short-Circuit Duration ............................................ 10s Continuous Power Dissipation (TA = +70°C) 5-Pin SC70 (Derate 2.5mW/°C above +70°C) ........ 200mW 8-Pin SOIC (Derate 5.88mW/°C above +70°C) ...... 471mW Operating Temperature Range ...................... -40°C to +85°C Junction Temperature ................................................ +150°C Storage Temperature Range ....................... -65°C to +150°C Lead Temperature (soldering, 10s) ............................... +300° Electrical and thermal stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other condition beyond those indicated in the operational sections of the specifications is not implied. Exposure to any absolute maximum rating conditions for extended periods may affect device reliability and lifetime. PACKAGE/ORDERING INFORMATION ORDER NUMBER PART CARRIER QUANTITY MARKING TSM917EUK+T Tape & Reel TAAA 3000 ORDER NUMBER PART CARRIER QUANTITY MARKING TSM917ESA+ Tube 97 Tape & Reel 2500 TSM917ESA+T TS917E Lead-free Program: Touchstone Semiconductor supplies only lead-free packaging. Consult Touchstone Semiconductor for products specified with wider operating temperature ranges. Page 2 TSM917DS r1p0 RTFDS TSM917 ELECTRICAL CHARACTERISTICS VCC = +5V, VEE = 0V, VIN+ = VREF, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C. See Note 1. PARAMETER SYMBOL Supply Voltage Range VCC Supply Current ICC IN+ Voltage Range VIN+ Input Offset Voltage VOS Input-Referred Hysteresis VHB Input Bias Current Power-Supply Rejection Ratio IB PSRR Output-Voltage Swing High VCC - VOH Output-Voltage Swing Low VOL Output Short-Circuit Current ISC High-to-Low Propagation Delay (Note 4) Low-to-High Propagation Delay (Note 4) Rise Time Fall Time tRISE tFALL Power-Up Time tON Reference Voltage tPDtPD+ VREF CONDITIONS Inferred from the PSRR test VCC = 1.6V MIN TA = +25°C TA = +25°C TA = +25°C VCC = 5V TA = TMIN to TMAX Inferred from the output swing test TA = +25°C (Note 2) TA = TMIN to TMAX (Note 3) TA = +25°C TA = TMIN to TMAX VCC = 1.8V to 5.5V TA = +25°C VCC = 5V, ISOURCE = 8mA TA = TMIN to TMAX TA = +25°C VCC = 1.8V, ISOURCE = 1mA TA = TMIN to TMAX TA = +25°C VCC = 5V, ISINK = 8mA TA = TMIN to TMAX TA = +25°C VCC = 1.8V, ISINK = 1mA TA = TMIN to TMAX VCC = 5V Sourcing, VO = VEE VCC = 1.8V VCC = 5V Sinking, VO = VCC VCC = 1.8V VCC = 1.8V VCC = 5V VCC = 1.8V VCC = 5V CL = 15pF CL = 15pF 0.75 0.80 VEE - 0.2 1 4 0.15 0.1 190 55 190 55 MAX UNITS 5.5 V 1.30 1.60 VCC + 0.2 5 10 μA 95 8 98 10 17 22 30 95 6 4 ∆VREF/ ∆VCC Reference Load Regulation ∆VREF/ ∆IOUT ∆IOUT = 10nA 1.227 1.200 1.245 95 TCVREF BW = 10Hz to 100kHz BW = 10Hz to 100kHz, CREF = 1nF VCC = 1.8V to 5.5V 600 215 0.1 ±0.2 V mV mV 1 2 1 400 500 200 300 400 500 200 300 nA mV/V mV mV mA µs µs µs µs 1.2 TA = +25°C TA = TMIN to TMAX Reference Voltage Temperature Coefficient Reference Output Voltage Noise Reference Line Regulation en TYP 1.8 ms 1.263 1.290 V ppm/°C µVRMS mV/V mV/nA Note 1: All specifications are 100% tested at TA = +25°C. Specification limits over temperature (TA = TMIN to TMAX) are guaranteed by design, not production tested. Note 2: VOS is defined as the center of the hysteresis band at the input. Note 3: The hysteresis-related trip points are defined by the edges of the hysteresis band, measured with respect to the center of the hysteresis band (i.e., VOS) (See Figure 2). Note 4: Specified with an input overdrive (VOVERDRIVE) of 100mV, and load capacitance of CL = 15pF. VOVERDRIVE is defined above and beyond the offset voltage and hysteresis of the comparator input. For the TSM917, reference voltage error should also be added. TSM917DS r1p0 Page 3 RTFDS TSM917 TYPICAL PERFORMANCE CHARACTERISTICS VCC = +5V; VEE = 0V; CL = 15pF; VOVERDRIVE = 100mV; TA = +25°C, unless otherwise noted. Supply Current vs Supply Voltage and Temperature Supply Current vs Temperature 1.3 1.1 SUPPLY CURENT - µA SUPPLY CURENT - µA 1 1.1 TA = +85°C 0.9 0.7 TA = +25°C TA = -40°C 0.5 0.9 VCC =+5V 0.8 VCC =+3V 0.7 0.6 VCC =+1.8V 0.5 0.4 1.5 2.5 4.5 3.5 5.5 -40 -15 60 85 TEMPERATURE - °C SUPPLY VOLTAGE - Volt Supply Current vs Output Transition Frequency Output Voltage Low vs. Sink Current 35 250 30 VCC =+1.8V 200 25 VCC =+5V 20 15 VOL - mV SUPPLY CURRENT - nA 35 10 VCC =+3V 150 VCC =+5V VCC =+3V 100 10 VCC =+1.8V 50 5 0 0 1 10 1k 100 10k 0 2 OUTPUT TRANSITION FREQUENCY - Hz 6 8 10 12 14 16 SINK CURRENT- mA Output Voltage Low vs. Sink Current and Temperature Output Voltage High vs Source Current 0.5 300 VCC =+1.8V TA = +85°C VCC – VOH - V TA = +25°C VOL - mV VCC =+3V 0.4 200 100 TA = -40°C 0.3 VCC =+5V 0.2 0.1 0 0 0 2 4 6 8 10 12 SINK CURRENT- mA Page 4 4 14 16 0 2 4 6 8 10 12 14 16 18 20 SOURCE CURRENT- mA TSM917DS r1p0 RTFDS TSM917 TYPICAL PERFORMANCE CHARACTERISTICS VCC = +5V; VEE = 0V; CL = 15pF; VOVERDRIVE = 100mV; TA = +25°C, unless otherwise noted. Output Voltage High Short-Circuit Sink Current vs Temperature vs Source Current and Temperature 0.6 120 0.5 100 SINK CURRENT- mA VCC – VOH - V TA = +85°C 0.4 0.3 TA = +25°C 0.2 TA = -40°C 0.1 VCC =+5V 80 60 VCC =+3V 40 VCC =+1.8V 20 0 0 0 4 8 12 16 20 -40 60 85 Offset Voltage vs Temperature Short-Circuit Source Current vs Temperature 140 2.6 120 2.4 100 VCC =+5V VOS - mV SOURCE CURRENT- mA 35 TEMPERATURE - °C SOURCE CURRENT- mA 80 60 VCC =+3V 2.2 VCC =+1.8V, 3V 2.0 1.8 40 1.6 VCC =+1.8V 20 0 VCC =+5V 1.4 -40 -15 10 35 60 85 -40 TEMPERATURE - °C -15 10 35 60 85 TEMPERATURE - °C Reference Voltage vs Temperature Hysteresis Voltage vs Temperature 1.246 5.5 REFERENCE VOLTAGE - V 5 4.5 VHB - mV 10 -15 4 3.5 3 2.5 VCC =+1.8V 1.245 1.244 VCC =+3V 1.243 VCC =+5V 1.242 1.241 -40 -15 10 35 TEMPERATURE - °C TSM917DS r1p0 60 85 -40 -15 10 35 60 85 TEMPERATURE - °C Page 5 RTFDS TSM917 TYPICAL PERFORMANCE CHARACTERISTICS VCC = +5V; VEE = 0V; CL = 15pF; VOVERDRIVE = 100mV; TA = +25°C, unless otherwise noted. Reference Voltage vs Reference Source Current Reference Voltage vs Supply Voltage 1.246 REFERENCE VOLTAGE - V REFERENCE VOLTAGE - V 1.246 1.245 1.244 1.243 1.242 1.241 1.5 1.244 1.243 VCC =+1.8V VCC =+5V 1.242 VCC =+3V 1.241 1.240 1.239 2.5 3.5 4.5 0 5.5 8 6 4 2 10 SUPPLY VOLTAGE - Volt SOURCE CURRENT- nA Reference Voltage vs Reference Sink Current Propagation Delay (tPD-) vs Temperature 1.2515 30 1.2505 VCC =+5V 25 VCC =+1.8V 1.2495 20 1.2485 tPD- - µs REFERENCE VOLTAGE - V 1.245 VCC =+5V 1.2475 1.2465 VCC =+3V 15 VCC =+1.8V 10 VCC =+3V 1.2455 5 1.2445 1.2435 0 0 2 4 6 8 -40 10 -15 35 10 60 85 TEMPERATURE - °C SINK CURRENT- nA Propagation Delay (tPD+) vs Temperature Propagation Delay (tPD-) vs Capacitive Load 140 100 120 VCC =+5V 80 VCC =+3V 60 VCC =+1.8V 80 tPD- - µs tPD+ - µs 100 60 VCC =+3V 40 VCC =+5V 40 VCC =+1.8V 20 20 0 0 -40 -15 10 35 TEMPERATURE - °C Page 6 60 85 0.01 0.1 1 10 100 1000 CAPACITIVE LOAD - nF TSM917DS r1p0 RTFDS TSM917 TYPICAL PERFORMANCE CHARACTERISTICS VCC = +5V; VEE = 0V; CL = 15pF; VOVERDRIVE = 100mV; TA = +25°C, unless otherwise noted. Propagation Delay (tPD+) vs Capacitive Load Propagation Delay (tPD-) vs Input Overdrive 80 120 VCC =+5V 70 100 VCC =+3V 60 VCC =+1.8V tPD- - µs tPD+ - µs 80 60 40 VCC =+5V 50 VCC =+3V 40 VCC =+1.8V 30 20 20 0 10 0.01 0.1 1 10 100 0 1000 CAPACITIVE LOAD - nF 10 20 30 40 50 INPUT OVERDRIVE - mV Propagation Delay (tPD-) at VCC = +5V Propagation Delay (tPD+) vs Input Overdrive 120 INPUT 100 VCC =+5V VCC =+3V 60 OUTPUT tPD+ - µs 80 40 20 VCC =+1.8V 0 0 10 20 30 40 50 20µs/DIV Propagation Delay (tPD+) at VCC = +5V Propagation Delay (tPD-) at VCC = +3V OUTPUT OUTPUT INPUT INPUT INPUT OVERDRIVE - mV 20µs/DIV TSM917DS r1p0 20µs/DIV Page 7 RTFDS TSM917 TYPICAL PERFORMANCE CHARACTERISTICS VCC = +5V; VEE = 0V; CL = 15pF; VOVERDRIVE = 100mV; TA = +25°C, unless otherwise noted. Propagation Delay (tPD-) at VCC = +1.8V INPUT OUTPUT OUTPUT INPUT Propagation Delay (tPD+) at VCC = +3V Propagation Delay (tPD+) at VCC = +1.8V 10kHz Transient Response at VCC = +1.8V OUTPUT OUTPUT INPUT 20µs/DIV INPUT 20µs/DIV 20µs/DIV 20µs/DIV Power-Up/Power-Down Transient Response OUTPUT OUTPUT INPUT INPUT 1kHz Transient Response at VCC = +5V 200µs/DIV Page 8 0.2s/DIV TSM917DS r1p0 RTFDS TSM917 PIN FUNCTIONS TSM917 5-pin 8-pin SOT23 SOIC 1 6 2 4 3 3 NAME OUT VEE IN+ 4 2 REF 5 — — 7 — 1, 5, 8 VCC INNC FUNCTION Comparator Output Negative Supply Voltage Comparator Noninverting Input 1.245V Reference Output and Comparator Inverting Input Positive Supply Voltage Comparator Inverting Input No Connection. Not internally connected. BLOCK DIAGRAMS DESCRIPTION OF OPERATION Guaranteed to operate from +1.8V supplies, the TSM917 analog comparator only draws 750nA supply current, features a robust input stage that can tolerate input voltages 200mV beyond the power supply rails, and includes an on-board +1.245V ±1.5% voltage reference. To insure clean output switching behavior, the TSM917 features 4mV internal hysteresis. The TSM917’s push-pull output drivers were designed to minimize supply-current surges while driving ±8mA loads with rail-to-rail output swings. TSM917DS r1p0 Input Stage Circuitry The robust design of the analog comparator’s input stage can accommodate any differential input voltage from VEE - 0.2V to VCC + 0.2V. Input bias currents are typically ±0.15nA so long as the applied input voltage remains between the supply rails. ESD protection diodes - connected internally to the supply rails - protect comparator inputs against overvoltage conditions. However, if the applied input voltage exceeds either or both supply rails, an increase in input current can occur when these ESD protection diodes start to conduct. Page 9 RTFDS TSM917 Output Stage Circuitry Many conventional analog comparators can draw orders of magnitude higher supply current when switching. Because of this behavior, additional power supply bypass capacitance may be required to provide additional charge storage during switching. The design of the TSM917’s rail-to-rail output stage implements a technique that virtually eliminates supply-current surges when output transitions occur. As shown on Page 4 of the Typical Operating Characteristics, the supply-current change as a function of output transition frequency exhibited by this analog comparator family is very small. Material benefits of this attribute to batterypower applications are the increase in operating time and in reducing the size of power-supply filter capacitors. can be bypassed with a low-leakage capacitor and is stable for any capacitive load. An external buffer – Figure 1: TSM917’s Internal VREF Output Equivalent Circuit TSM917’s Internal +1.245V VREF The TSM917’s internal +1.245V voltage reference exhibits a typical temperature coefficient of 95ppm/°C over the full -40°C to +85°C temperature range. An equivalent circuit for the reference section is illustrated in Figure 1. Since the output impedance of the voltage reference is typically 200kΩ, its output such as the TS1001 – can be used to buffer the voltage reference output for higher output current drive or to reduce reference output impedance. APPLICATIONS INFORMATION Low-Voltage, Low-Power Operation Because it was designed specifically for any lowpower, battery-operated application, the TSM917 analog comparator is an excellent choice. Under nominal conditions, approximate operating times for this analog comparator is illustrated in Table 1 for a number of battery types and their corresponding charge capacities. Internal Hysteresis As a result of circuit noise or unintended parasitic feedback, many analog comparators often break into oscillation within their linear region of operation especially when the applied differential input voltage approaches 0V (zero volt). Externally-introduced hysteresis is a well-established technique to stabilizing analog comparator behavior and requires external components. As shown in Figure 2, adding comparator hysteresis creates two trip points: VTHR (for the rising input voltage) and VTHF (for the falling input voltage). The hysteresis band (VHB) is defined as the voltage difference between the two trip points. When a comparator’s input voltages are equal, hysteresis effectively forces one comparator input to Table 1: Battery Applications using the TSM917 Alkaline (2 Cells) No 3.0 1.8 2000 TSM917 OPERATING TIME (hrs) 6 2.5 x 10 Nickel-Cadmium (2 Cells) Yes 2.4 1.8 750 937,500 Lithium-Ion (1 Cell) Nickel-Metal- Hydride (2 Cells) Yes 3.5 2.7 1000 1.25 x 10 6 Yes 2.4 1.8 1000 1.25 x 10 6 BATTERY TYPE Page 10 RECHARGEABLE VFRESH (V) VEND-OF-LIFE (V) CAPACITY, AA SIZE (mA-h) TSM917DS r1p0 RTFDS TSM917 move quickly past the other input, moving the input out of the region where oscillation occurs. Figure 2 illustrates the case in which an IN- input is a fixed voltage and an IN+ is varied. If the input signals were reversed, the figure would be the same with an inverted output. To save cost and external pcb area, an internal 4mV hysteresis circuit was added to the TSM917. point is (VREF - VOUT)/R2. In solving for R2, there are two formulas – one each for the two possible output states: R2 = VREF/IR2 or R2 = (VCC - VREF)/IR2 From the results of the two formulae, the smaller of the two resulting resistor values is chosen. For example, when using the TSM917 (VREF = 1.245V) at a VCC = 3.3V and if IR2 = 0.2μA is chosen, then the formulae above produce two resistor values: 6.23MΩ and 10.24MΩ - the 6.2MΩ standard value for R2 is selected. Figure 2: TSM917’s Threshold Hysteresis Band Adding Hysteresis to the TSM917 The TSM917 exhibits an internal hysteresis band (VHB) of 4mV. Additional hysteresis can be generated with three external resistors using positive feedbackas shown in Figure 3. Unfortunately, this method also reduces the hysteresis response time. The design procedure below can be used to calculate resistor values. 2) Next, the desired hysteresis band (VHYSB) is set. In this example, VHYSB is set to 100mV. 3) Resistor R1 is calculated according to the following equation: R1 = R2 x (VHB/VCC) and substituting the values selected in 1) and 2) above yields: R1 = 6.2MΩ x (100mV/3.3V) = 187.88kΩ The 187kΩ standard value for R1 is selected. 4) The trip point for VIN rising (VTHR) is chosen such that VTHR > VREF x (R1 + R2)/R2 (where VTHF is the trip point for VIN falling). This is the threshold voltage at which the comparator switches its output from low to high as VIN rises above the trip point. In this example, VTHR is set to 3V. 5) With the VTHR from Step 4 above, resistor R3 is then computed as follows: Figure 3: Using Three Resistors Introduces Additional Hysteresis in the TSM917. 1) Setting R2. As the leakage current at the IN pin is under 2nA, the current through R2 should be at least 0.2μA to minimize offset voltage errors caused by the input leakage current. The current through R2 at the trip TSM917DS r1p0 R3 = 1/[VTHR/(VREF x R1) - (1/R1) - (1/R2)] R3 = 1/[3V/(1.245V x 187kΩ) - (1/187kΩ) - (1/6.2MΩ)] = 135.56kΩ In this example, a 137kΩ, 1% standard value resistor is selected for R3. Page 11 RTFDS TSM917 6) The trip voltages and hysteresis band should be verified as follows: For VIN rising: VTHR = VREF x R1 x [(1/R1) + (1 / R2) + (1 / R3)] = 3V For VIN falling: VTHF = VTHR - (R1 x VCC/R2) = 2.9V and Hysteresis Band = VTHR – VTHF = 100mV Page 12 PC Board Layout and Power-Supply Bypassing While power-supply bypass capacitors are not typically required, it is always good engineering practice to use 0.1uF bypass capacitors close to the device’s power supply pins when the power supply impedance is high, the power supply leads are long, or there is excessive noise on the power supply traces. To reduce stray capacitance, it is also good engineering practice to make signal trace lengths as short as possible. Also recommended are a ground plane and surface mount resistors and capacitors. TSM917DS r1p0 RTFDS TSM917 PACKAGE OUTLINE DRAWING 5-Pin SOT23 Package Outline Drawing (N.B., Drawings are not to scale) TSM917DS r1p0 Page 13 RTFDS TSM917 PACKAGE OUTLINE DRAWING 8-Pin SOIC Package Outline Drawing (N.B., Drawings are not to scale) Information furnished by Touchstone Semiconductor is believed to be accurate and reliable. However, Touchstone Semiconductor does not assume any responsibility for its use nor for any infringements of patents or other rights of third parties that may result from its use, and all information provided by Touchstone Semiconductor and its suppliers is provided on an AS IS basis, WITHOUT WARRANTY OF ANY KIND. Touchstone Semiconductor reserves the right to change product specifications and product descriptions at any time without any advance notice. No license is granted by implication or otherwise under any patent or patent rights of Touchstone Semiconductor. Touchstone Semiconductor assumes no liability for applications assistance or customer product design. Customers are responsible for their products and applications using Touchstone Semiconductor components. To minimize the risk associated with customer products and applications, customers should provide adequate design and operating safeguards. Trademarks and registered trademarks are the property of their Page 14 Touchstone Semiconductor, Inc. 630 Alder Drive, Milpitas, CA 95035 +1 (408) 215 - 1220 ▪ www.touchstonesemi.com TSM917DS r1p0 RTFDS