TSM917

TSM917 1.8V Nanopower Comparator with Internal 1.245V Reference FEATURES ♦ 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 DESCRIPTION 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 ORDER NUMBER PART CARRIER QUANTITY MARKING TSM917EUK+T TAAA Tape & Reel TSM917ESA+ 3000 TSM917ESA+T TS917E Tube Tape & Reel 97 2500 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 Supply Voltage Range Supply Current IN+ Voltage Range Input Offset Voltage Input-Referred Hysteresis Input Bias Current Power-Supply Rejection Ratio Output-Voltage Swing High SYMBOL VCC ICC VIN+ VOS VHB IB PSRR VCC - VOH CONDITIONS Inferred from the PSRR test VCC = 1.6V MIN TA = +25°C 1.8 0.75 0.80 VEE - 0.2 1 4 0.15 0.1 190 55 190 55 95 8 98 10 17 22 30 95 6 4 1.2 TA = +25°C TA = TMIN to TMAX BW = 10Hz to 100kHz BW = 10Hz to 100kHz, CREF = 1nF VCC = 1.8V to 5.5V 1.227 1.200 1.245 95 600 215 0.1 ±0.2 1.263 1.290 TYP MAX 5.5 1.30 1.60 VCC + 0.2 5 10 1 2 1 400 500 200 300 400 500 200 300 UNITS V μA V mV mV nA mV/V mV Output-Voltage Swing Low VOL Output Short-Circuit Current High-to-Low Propagation Delay (Note 4) Low-to-High Propagation Delay (Note 4) Rise Time Fall Time Power-Up Time Reference Voltage Reference Voltage Temperature Coefficient Reference Output Voltage Noise Reference Line Regulation Reference Load Regulation ISC tPDtPD+ tRISE tFALL tON VREF TCVREF en ∆VREF/ ∆VCC 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 mV mA µs µs µs µs ms V ppm/°C µVRMS mV/V mV/nA ∆VREF/ ∆IOUT ∆IOUT = 10nA 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 1.3 1.1 1 SUPPLY CURENT - µA SUPPLY CURENT - µA 1.1 TA = +85°C 0.9 0.9 0.8 VCC =+3V 0.7 0.6 VCC =+1.8V 0.5 0.4 1.5 2.5 3.5 4.5 5.5 -40 -15 10 35 60 85 SUPPLY VOLTAGE - Volt TEMPERATURE - °C VCC =+5V Supply Current vs Temperature 0.7 TA = +25°C TA = -40°C 0.5 Supply Current vs Output Transition Frequency 35 30 SUPPLY CURRENT - nA 25 VCC =+5V VOL - mV 20 15 10 VCC =+1.8V 5 0 1 10 100 1k 10k OUTPUT TRANSITION FREQUENCY - Hz Output Voltage Low vs. Sink Current and Temperature 300 TA = +85°C VCC – VOH - V 200 VOL - mV TA = +25°C 0.5 50 0 150 250 200 Output Voltage Low vs. Sink Current VCC =+1.8V VCC =+5V VCC =+3V VCC =+3V 100 0 2 4 6 8 10 12 14 16 SINK CURRENT- mA Output Voltage High vs Source Current VCC =+1.8V 0.4 0.3 0.2 0.1 0 VCC =+3V VCC =+5V 100 TA = -40°C 0 0 2 4 6 8 10 12 14 16 SINK CURRENT- mA 0 2 4 6 8 10 12 14 16 18 20 SOURCE CURRENT- mA Page 4 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 0.5 0.4 0.3 0.2 TA = -40°C 0.1 0 0 4 8 12 16 20 SOURCE CURRENT- mA TA = +25°C SINK CURRENT- mA TA = +85°C VCC – VOH - V 120 100 80 60 40 20 0 -40 -15 10 35 60 85 TEMPERATURE - °C VCC =+1.8V VCC =+5V VCC =+3V Short-Circuit Source Current vs Temperature 140 120 SOURCE CURRENT- mA 100 80 60 40 20 0 -40 -15 10 35 60 85 TEMPERATURE - °C VCC =+1.8V VCC =+5V 2.6 2.4 2.2 2.0 1.8 1.6 1.4 -40 Offset Voltage vs Temperature VCC =+3V VOS - mV VCC =+1.8V, 3V VCC =+5V -15 10 35 60 85 TEMPERATURE - °C Hysteresis Voltage vs Temperature 5.5 REFERENCE VOLTAGE - V 5 4.5 VHB - mV 4 3.5 3 2.5 -40 -15 10 35 60 85 TEMPERATURE - °C 1.246 1.245 1.244 1.243 1.242 1.241 Reference Voltage vs Temperature VCC =+1.8V VCC =+3V VCC =+5V -40 -15 10 35 60 85 TEMPERATURE - °C TSM917DS r1p0 Page 5 RTFDS TSM917 TYPICAL PERFORMANCE CHARACTERISTICS VCC = +5V; VEE = 0V; CL = 15pF; VOVERDRIVE = 100mV; TA = +25°C, unless otherwise noted. Reference Voltage vs Supply Voltage 1.246 REFERENCE VOLTAGE - V 1.245 1.244 1.243 1.242 REFERENCE VOLTAGE - V Reference Voltage vs Reference Source Current 1.246 1.245 1.244 1.243 1.242 1.241 1.240 1.239 2.5 3.5 4.5 5.5 0 2 4 6 8 10 SUPPLY VOLTAGE - Volt SOURCE CURRENT- nA VCC =+3V VCC =+5V VCC =+1.8V 1.241 1.5 Reference Voltage vs Reference Sink Current 1.2515 REFERENCE VOLTAGE - V 1.2505 1.2495 1.2485 1.2475 1.2465 1.2455 1.2445 1.2435 0 2 4 6 8 10 SINK CURRENT- nA VCC =+3V 5 0 VCC =+5V tPD- - µs VCC =+1.8V 20 15 10 30 25 Propagation Delay (tPD-) vs Temperature VCC =+5V VCC =+3V VCC =+1.8V -40 -15 10 35 60 85 TEMPERATURE - °C Propagation Delay (tPD+) vs Temperature 140 120 100 tPD+ - µs tPD- - µs 80 60 40 20 0 -40 -15 10 35 60 85 TEMPERATURE - °C VCC =+1.8V VCC =+3V VCC =+5V Propagation Delay (tPD-) vs Capacitive Load 100 80 VCC =+1.8V 60 VCC =+3V 40 VCC =+5V 20 0 0.01 0.1 1 10 100 1000 CAPACITIVE LOAD - nF Page 6 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 120 VCC =+5V 100 VCC =+3V 80 tPD+ - µs 60 40 20 0 0.01 0.1 1 10 100 1000 CAPACITIVE LOAD - nF tPD- - µs VCC =+1.8V Propagation Delay (tPD-) vs Input Overdrive 80 70 60 50 40 30 20 10 0 10 20 30 40 50 INPUT OVERDRIVE - mV Propagation Delay (tPD-) at VCC = +5V VCC =+5V VCC =+3V VCC =+1.8V Propagation Delay (tPD+) vs Input Overdrive 120 100 VCC =+5V 80 tPD+ - µs 60 40 20 0 0 10 20 30 40 50 INPUT OVERDRIVE - mV VCC =+1.8V VCC =+3V OUTPUT INPUT 20µs/DIV Propagation Delay (tPD+) at VCC = +5V Propagation Delay (tPD-) at VCC = +3V OUTPUT INPUT 20µs/DIV OUTPUT INPUT 20µs/DIV TSM917DS r1p0 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 = +3V Propagation Delay (tPD-) at VCC = +1.8V INPUT OUTPUT 20µs/DIV OUTPUT INPUT 20µs/DIV Propagation Delay (tPD+) at VCC = +1.8V 10kHz Transient Response at VCC = +1.8V INPUT OUTPUT OUTPUT INPUT 20µs/DIV 1kHz Transient Response at VCC = +5V 20µs/DIV Power-Up/Power-Down Transient Response OUTPUT INPUT 200µs/DIV OUTPUT INPUT 0.2s/DIV Page 8 TSM917DS r1p0 RTFDS TSM917 PIN FUNCTIONS TSM917 5-pin 8-pin SOT23 SOIC 1 6 2 4 3 3 4 5 — — 2 7 — 1, 5, 8 NAME OUT VEE IN+ REF 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. 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. TSM917DS r1p0 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. 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 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 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 Table 1: Battery Applications using the TSM917 BATTERY TYPE Alkaline (2 Cells) Nickel-Cadmium (2 Cells) Lithium-Ion (1 Cell) Nickel-Metal- Hydride (2 Cells) RECHARGEABLE No Yes Yes Yes VFRESH (V) 3.0 2.4 3.5 2.4 VEND-OF-LIFE (V) 1.8 1.8 2.7 1.8 CAPACITY, AA SIZE (mA-h) 2000 750 1000 1000 TSM917 OPERATING TIME (hrs) 6 2.5 x 10 937,500 1.25 x 10 1.25 x 10 6 6 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 Page 10 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. 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. 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. 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 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. Page 12 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