EVALUATION KIT AVAILABLE MAX9025-MAX9028 UCSP, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference General Description The MAX9025/MAX9028 nanopower comparators in space-saving chip-scale (UCSPTM) packages feature Beyond-the-RailsTM inputs and are guaranteed to operate down to +1.8V. The MAX9025/MAX9026 feature an on-board 1.236V 1% reference and draw an ultralow supply current of only 1A, while the MAX9027- MAX9028 (without reference) require just 0.6A of supply current. These features make the MAX9025- MAX9028 family of comparators ideal for all 2-cell batterymonitoring/management applications. The unique design of the output stage limits supplycurrent surges while switching, virtually eliminating the supply glitches typical of many other comparators. This design also minimizes overall power consumption under dynamic conditions. The MAX9025/MAX9027 have a push-pull output stage that sinks and sources current. Large internal-output drivers allow rail-to-rail output swing with loads up to 5mA. The MAX9026/MAX9028 have an open-drain output stage that makes them suitable for mixed-voltage system design. All devices are available in the miniature 6-bump UCSP packages. Refer to the MAX9117 data sheet for similar comparators in 5-pin SC70 packages and the MAX9017 data sheet for similar dual comparators in 8-pin SOT23 packages. Applications Space-Saving UCSP Package (1mm x 1.52mm) Ultra-Low Supply Current * 0.6A (MAX9027/MAX9028) * 1A with Reference (MAX9025/MAX9026) Guaranteed to Operate Down to +1.8V Internal 1.236V 1% Reference (MAX9025/ MAX9026) Input Voltage Range Extends 200mV Beyond-the-Rails CMOS Push-Pull Output with 5mA Drive Capability (MAX9025/MAX9027) Open-Drain Output Versions Available (MAX9026/ MAX9028) Crowbar-Current-Free Switching Internal Hysteresis for Clean Switching No Phase Reversal for Overdriven Inputs Ordering Information PART TEMP RANGE MAX9025EBT+T -40C to +85C 6 UCSP ADB MAX9026EBT+T -40C to +85C 6 UCSP ADC MAX9027EBT+T -40C to +85C 6 UCSP ADD MAX9028EBT+T -40C to +85C 6 UCSP ADE Pin Configurations TOP VIEW (BUMPS ON BOTTOM) 1 Selector Guide INTERNAL REFERENCE OUTPUT TYPE SUPPLY CURRENT (A) MAX9025 Yes Push-Pull 1.0 MAX9026 Yes Open-Drain 1.0 MAX9027 No Push-Pull 0.6 MAX9028 No Open-Drain 0.6 Beyond-the-Rails and UCSP are trademarks of Maxim Integrated Products, Inc. B A IN+ VCC MAX9025- MAX9028 2 REF (VEE) OUT 3 IN- VEE Typical Application Circuit appears at end of data sheet. 19-3241; Rev 1; 6/11 BUMPPACKAGE +Denotes lead(Pb)-free/RoHS-compliant package. T = Tape and reel. 2-Cell Battery Monitoring/Management Ultra-Low-Power Systems Mobile Communications Notebooks and PDAs Sensing at Ground or Supply Line Telemetry and Remote Systems Medical Instruments PART Features ( ) MAX9027/MAX9028 PINS UCSP TOP MARK MAX9025-MAX9028 UCSP, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference Absolute Maximum Ratings Supply Voltage (VCC to VEE).................................................+6V Voltage Inputs (IN+, IN-, REF)....... (VEE - 0.3V) to (VCC + 0.3V) Output Voltage MAX9025/MAX9027................. (VEE - 0.3V) to (VCC + 0.3V) MAX9026/MAX9028................................(VEE - 0.3V) to +6V Current into Input Pins........................................................20mA Output Current...................................................................50mA Output Short-Circuit Duration................................................. 10s Continuous Power Dissipation (TA = +70C) 6-Bump UCSP (derate 3.9mW/C above +70C).........308mW Operating Temperature Range............................ -40C to +85C Junction Temperature.......................................................+150C Storage Temperature Range............................. -65C to +150C Bump Temperature (soldering) Reflow............................. +235C 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 conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Electrical Characteristics-MAX9025/MAX9026 (with REF) (VCC = +5V, VEE = 0V, VIN+ = VREF, TA = -40C to +85C, unless otherwise noted. Typical values are at TA = +25C.) (Note 1) PARAMETER SYMBOL Supply Voltage Range VCC Supply Current ICC CONDITIONS MIN Inferred from the PSRR test 1.8 VCC = 1.8V VCC = 5V TA = +25C VIN+ Inferred from output swing test Input Offset Voltage VOS (Note 2) Input-Referred Hysteresis VHB (Note 3) Power-Supply Rejection Ratio Output Voltage Swing High Output Voltage Swing Low Output Leakage Current IB PSRR VCC VOH VOL ILEAK www.maximintegrated.com 1.7 VEE 0.2 VCC + 0.2 0.3 5 10 4 TA = +25C MAX9025, VCC = 1.8V, ISOURCE = 1mA TA = +25C VCC = 5V, ISINK = 6mA TA = +25C VCC = 1.8V, ISINK = 1mA TA = +25C 0.1 1 250 350 TA = TMIN to TMAX 450 56 TA = TMIN to TMAX mV 200 nA mV/V mV 300 250 TA = TMIN to TMAX 350 450 57 TA = TMIN to TMAX MAX9026 only, VO = 5.5V V mV 1 2 MAX9025, VCC = 5V, ISOURCE = 6mA A 2.2 0.15 VCC = 1.8V to 5.5V Sinking, VO = VCC V 1.5 TA = TMIN to TMAX ISC UNITS 5.5 1.0 TA = TMIN to TMAX TA = +25C Sourcing, VO = VEE Output Short-Circuit Current TA = +25C MAX 0.8 TA = TMIN to TMAX IN+ Voltage Range Input Bias Current TYP 200 mV 300 0.001 VCC = 5V 35 VCC = 1.8V 3 VCC = 5V 33 VCC = 1.8V 3 1 A mA Maxim Integrated 2 MAX9025-MAX9028 UCSP, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference Electrical Characteristics-MAX9025/MAX9026 (with REF) (continued) (VCC = +5V, VEE = 0V, VIN+ = VREF, TA = -40C to +85C, unless otherwise noted. Typical values are at TA = +25C.) (Note 1) PARAMETER High-to-Low Propagation Delay (Note 4) SYMBOL tPD- CONDITIONS MIN TYP VCC = 1.8V 7 VCC = 5V 6 MAX9025 only MAX UNITS s VCC = 1.8V 11 VCC = 5V 28 VCC = 1.8V 12 Low-to-High Propagation Delay (Note 4) tPD+ Rise Time tRISE MAX9025 only, CL = 15pF 1.6 s Fall Time tFALL CL = 15pF 0.2 s Power-Up Time Reference Voltage Reference Voltage Temperature Coefficient MAX9026 only, RPULLUP = 100k VCC = 5V 31 tON VREF s 1.2 TA = +25C 1.224 TA = TMIN to TMAX 1.205 TCREF 1.236 ms 1.248 V 1.267 ppm/ C 40 BW = 10Hz to 100kHz 29 BW = 10Hz to 6kHz 60 Reference Output Voltage Noise EN Reference Line Regulation DVREF/ DVCC VCC = 1.8V to 5.5V 0.5 mV/V Reference Load Regulation DVREF/ DIOUT DIOUT = 0nA to 100nA 0.03 mV/ nA CREF = 1nF VRMS Electrical Characteristics-MAX9027/MAX9028 (without REF) (VCC = +5V, VEE = 0V, VCM = 0V, TA = -40C to +85C, unless otherwise noted. Typical values are at TA = +25C.) (Note 1) PARAMETER SYMBOL Supply Voltage Range VCC Supply Current ICC CONDITIONS Inferred from the PSRR test MIN VCC = 1.8V Input Common-Mode Voltage Range VCC = 5V TA = +25C Inferred from the CMRR test Input Offset Voltage VOS -0.2V VCM (VCC + 0.2V) (Note 2) Input-Referred Hysteresis VHB -0.2V VCM (VCC + 0.2V) (Note 3) IB TA = +25C UNITS 5.5 V 0.75 0.6 1.0 A 1.25 VEE 0.2 VCC + 0.2 0.3 TA = TMIN to TMAX TA = +25C MAX 0.45 TA = TMIN to TMAX VCM Input Bias Current TYP 1.8 5 10 4 0.15 TA = TMIN to TMAX V mV mV 1 2 nA Power-Supply Rejection Ratio PSRR VCC = 1.8V to 5.5V 0.1 1 mV/V Common-Mode Rejection Ratio CMRR (VEE - 0.2V) VCM (VCC + 0.2V) 0.5 3 mV/V www.maximintegrated.com Maxim Integrated 3 MAX9025-MAX9028 UCSP, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference Electrical Characteristics-MAX9027/MAX9028 (without REF) (continued) (VCC = +5V, VEE = 0V, VCM = 0V, TA = -40C to +85C, unless otherwise noted. Typical values are at TA = +25C.) (Note 1) PARAMETER Output Voltage Swing High Output Voltage Swing Low Output Leakage Current SYMBOL CONDITIONS MAX9027 only, VCC = TA = +25C 5V, ISOURCE = 5mA TA = TMIN to TMAX VCC - VOH MAX9028 only, VCC = TA = +25C 1.8V, ISOURCE = 1mA TA = TMIN to TMAX VOL ILEAK VCC = 5V, ISINK = 5mA TA = +25C VCC = 1.8V, ISINK = 1mA TA = +25C Output Short-Circuit Current ISC Sourcing, VO = VCC High-to-Low Propagation Delay (Note 4) tPDMAX9027 only Low-to-High Propagation Delay (Note 4) tPD+ MAX9028 only TYP MAX 191 400 500 58 mV 400 500 56 TA = TMIN to TMAX VCC = 5V 200 UNITS 300 191 TA = TMIN to TMAX MAX9028 only, VO = 5.5V Sourcing, VO = VEE MIN 200 mV 300 0.001 1 A 35 VCC = 1.8V 3 VCC = 5V 33 VCC = 1.8V 3 VCC = 1.8V 16 VCC = 5V 14 VCC = 1.8V 15 VCC = 5V 40 VCC = 1.8V, RPULLUP = 100k 16 VCC = 5V, RPULLUP = 100k 45 mA s s Rise Time tRISE MAX9027 only, CL = 15pF 1.6 s Fall Time tFALL CL = 15pF 0.2 s 1.2 ms Power-Up Time tON Note 1: All specifications are 100% tested at TA = +25C. 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 as the edges of the hysteresis band, measured with respect to the center of the band (i.e., VOS) (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 MAX9025/MAX9026, reference voltage error should also be added. www.maximintegrated.com Maxim Integrated 4 MAX9025-MAX9028 UCSP, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference Typical Operating Characteristics (VCC = +5V, VEE = 0V, CL = 15pF, VOVERDRIVE = 100mV, TA = +25C, unless otherwise noted.) TA = +25C TA = -40C 400 600 1.5 2.5 3.5 300 5.5 4.5 1.5 2.5 VCC = 5V VCC = 3V 500 400 300 -15 10 60 85 OUTPUT VOLTAGE LOW vs. SINK CURRENT 600 VCC = 3V VCC = 1.8V 400 200 0 VCC = 5V 0 2 4 VCC = 3V 20 15 VCC = 5V 10 6 SINK CURRENT (mA) www.maximintegrated.com 8 10 0.1 MAX9025-28 toc03 35 60 85 35 1 10 25 VCC = 3V 20 15 VCC = 5V 10 5 0 100 VCC = 1.8V 0.1 1 10 100 TRANSITION FREQUENCY (kHz) OUTPUT VOLTAGE LOW vs. SINK CURRENT MAX9025/MAX9027 OUTPUT VOLTAGE HIGH vs. SOURCE CURRENT TA = +25C 400 TA = +85C 200 TA = -40C 0 30 TRANSITION FREQUENCY (kHz) 600 0 40 VCC = 1.8V 800 OUTPUT VOLTAGE LOW (mV) MAX9025-28 toc07 OUTPUT VOLTAGE LOW (mV) 800 10 MAX9027/MAX9028 SUPPLY CURRENT vs. OUTPUT TRANSITION FREQUENCY 5 35 -15 MAX9025/MAX9026 SUPPLY CURRENT vs. OUTPUT TRANSITION FREQUENCY 25 TEMPERATURE (C) -40 TEMPERATURE (C) 30 0 600 5.5 35 VCC = 1.8V -40 4.5 MAX9025-28 toc08 600 800 VCC = 1.8V MAX9025-28 toc05 700 40 SUPPLY CURRENT (A) MAX9025-28 toc04 SUPPLY CURRENT (nA) 800 VCC = 3V SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V) MAX9027/MAX9028 SUPPLY CURRENT vs. TEMPERATURE 3.5 VCC = 5V 1000 MAX9025-28 toc06 800 500 1200 2 4 6 SINK CURRENT (mA) 8 10 800 MAX9025-28 toc09 TA = -40C 600 SUPPLY CURRENT (nA) TA = +25C TA = +85C MAX9025/MAX9026 SUPPLY CURRENT vs. TEMPERATURE SUPPLY CURRENT (A) 1000 700 OUTPUT VOLTAGE HIGH (VCC - VOH, mV) SUPPLY CURRENT (nA) TA = +85C 800 SUPPLY CURRENT (nA) MAX9025-28 toc01 1200 MAX9027/MAX9028 SUPPLY CURRENT vs. SUPPLY VOLTAGE MAX9025-28 toc02 MAX9025/MAX9026 SUPPLY CURRENT vs. SUPPLY VOLTAGE 600 VCC = 1.8V VCC = 3V 400 200 VCC = 5V 0 0 2 4 6 8 10 SOURCE CURRENT (mA) Maxim Integrated 5 MAX9025-MAX9028 UCSP, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference Typical Operating Characteristics (continued) (VCC = +5V, VEE = 0V, CL = 15pF, VOVERDRIVE = 100mV, TA = +25C, unless otherwise noted.) 400 TA = +85C 200 4 6 8 VCC = 5V 20 VCC = 3V 10 VCC = 1.8V -40 -15 10 35 60 20 VCC = 3V 10 VCC = 1.8V -15 -40 10 35 60 OFFSET VOLTAGE vs. TEMPERATURE HYSTERESIS VOLTAGE vs. TEMPERATURE INPUT BIAS CURRENT vs. INPUT BIAS VOLTAGE VCC = 3V 0.3 VCC = 3V VCC = 1.8V 3.5 3.0 VCC = 5V 2.5 -15 10 35 60 2.0 85 -40 -15 10 35 60 1.000 INPUT BIAS CURRENT (IN-) (nA) VCC = 1.8V 4.0 IN+ = 2.5V 0.600 0.200 -0.200 -0.600 -1.000 85 -0.5 0.5 1.5 2.5 3.5 4.5 MAX9025/MAX9026 REFERENCE VOLTAGE vs. TEMPERATURE MAX9025/MAX9026 REFERENCE VOLTAGE vs. TEMPERATURE MAX9025/MAX9026 REFERENCE VOLTAGE vs. SUPPLY VOLTAGE VCC = 5V 1.2350 1.2340 1.2330 -40 -15 10 35 TEMPERATURE (C) www.maximintegrated.com 60 85 5 DEVICES 1.237 1.235 1.233 1.231 -40 -15 10 35 TEMPERATURE (C) 60 85 1.238 5.5 MAX9025-28 toc18 VCC = 1.8V 1.2360 1.239 REFERENCE VOLTAGE (V) VCC = 3V REFERENCE VOLTAGE (V) INPUT BIAS VOLTAGE (IN-) (V) MAX9025-28 toc17 TEMPERATURE (C) MAX9025-28 toc16 TEMPERATURE (C) 1.2370 85 MAX9025-28 toc15 TEMPERATURE (C) VCC = 5V REFERENCE VOLTAGE (V) VCC = 5V TEMPERATURE (C) 0.5 -40 30 0 85 VOUT = VEE SOURCE CURRENT (mA) 0.8 0 40 MAX9025-28 toc12 30 0 10 MAX9025-28 toc13 OFFSET VOLTAGE (mV) 1.0 2 VOUT = VCC MAX9025-28 toc14 0 HYSTERESIS VOLTAGE (mV) 0 TA = -40C TA = +25C MAX9025/MAX9027 SHORT-CIRCUIT SOURCE CURRENT vs. TEMPERATURE SHORT-CIRCUIT SINK CURRENT (mA) 600 40 SHORT-CIRCUIT SINK CURRENT (mA) MAX9025-28 toc10 OUTPUT VOLTAGE HIGH (VCC - VOH, mV) 800 SHORT-CIRCUIT SINK CURRENT vs. TEMPERATURE MAX9025-28 toc11 MAX9025/MAX9027 OUTPUT VOLTAGE HIGH vs. SOURCE CURRENT 1.237 1.236 1.235 1.234 1.5 2.5 3.5 4.5 5.5 SUPPLY VOLTAGE (V) Maxim Integrated 6 MAX9025-MAX9028 UCSP, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference Typical Operating Characteristics (continued) (VCC = +5V, VEE = 0V, CL = 15pF, VOVERDRIVE = 100mV, TA = +25C, unless otherwise noted.) VCC = 1.8V 15 tPD- (s) VCC = 1.8V 1.236 VCC = 5V 50 40 tPD+ (s) VCC = 3V 10 VCC = 5V 1.234 MAX9025/MAX9027 PROPAGATION DELAY (tPD+) vs. TEMPERATURE 5 MAX9025-28 toc21 VCC = 3V 1.238 20 MAX9025-28 toc19 REFERENCE VOLTAGE (V) 1.240 PROPAGATION DELAY (tPD-) vs. TEMPERATURE MAX9025-28 toc20 MAX9025/MAX9026 REFERENCE VOLTAGE vs. REFERENCE CURRENT VCC = 5V 30 VCC = 3V 20 10 VCC = 1.8V -100 -50 0 50 0 100 -40 REFERENCE CURRENT (nA) VCC = 3V 1 10 80 70 60 VCC = 1.8V 50 40 VCC = 3V VCC = 5V 10 1 10 100 0 0 10 20 30 40 50 CAPACITIVE LOAD (nF) INPUT OVERDRIVE (mV) MAX9025/MAX9027 PROPAGATION DELAY (tPD+) vs. INPUT OVERDRIVE MAX9026/MAX9028 PROPAGATION DELAY (tPD+) vs. PULLUP RESISTANCE PROPAGATION DELAY (VCC = 5V) MAX9025-28 toc25 200 175 150 30 tPD+ (s) VCC = 5V 40 tPD+ (s) 0.1 85 20 VCC = 1.8V 0.01 60 CAPACITIVE LOAD (nF) 50 VCC = 3V 10 VCC = 1.8V 10 20 30 INPUT OVERDRIVE (mV) www.maximintegrated.com MAX9025 toc27 +100mV IN+ -100mV 125 100 75 20 0 20 0 100 35 PROPAGATION DELAY (tPD-) vs. INPUT OVERDRIVE VCC = 5V VCC = 3V 10 0.1 10 30 60 0 30 VCC = 5V 0.01 -15 MAX9025-28 toc26 0 -40 TEMPERATURE (C) tPD- (s) 10 5 0 85 60 MAX9025-28 toc23 MAX9025-28 toc22 VCC = 1.8V 35 MAX9025/MAX9027 PROPAGATION DELAY (tPD+) vs. CAPACITIVE LOAD 40 tPD+ (s) tPD- (s) 15 10 TEMPERATURE (C) PROPAGATION DELAY (tPD-) vs. CAPACITIVE LOAD 20 -15 MAX9025-28 toc24 1.232 40 50 50 VCC = 5V 25 VCC = 3V 0 10 OUT 2V/div 0V VCC = 1.8V 100 1000 10000 20s/div PULLUP RESISTANCE (k) Maxim Integrated 7 MAX9025-MAX9028 UCSP, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference Typical Operating Characteristics (continued) (VCC = +5V, VEE = 0V, CL = 15pF, VOVERDRIVE = 100mV, TA = +25C, unless otherwise noted.) PROPAGATION DELAY (VCC = 1.8V) PROPAGATION DELAY (VCC = 3V) MAX9025 toc29 MAX9025 toc28 1kHz FREQUENCY RESPONSE (VCC = 5V) MAX9025 toc30 +100mV +100mV IN+ IN+ IN+ -100mV -100mV -100mV OUT 1V/div OUT 2V/div 0V 0V OUT 1V/div 0V 20s/div 20s/div 10kHz FREQUENCY RESPONSE (VCC = 1.8V) 200s/div REFERENCE RESPONSE TO SUPPLY VOLTAGE TRANSIENT (CREF = 10nF) MAX9025 toc31 +100mV MAX9025 toc32 POWER-UP/POWER-DOWN RESPONSE MAX9025 toc33 +100mV REF 200mV/div IN+ -100mV VCC 2V/div 5V VCC 1V/div OUT 1V/div 0V OUT 2V/div 1.8V 0V 20s/div www.maximintegrated.com 0V 1ms/div 40s/div Maxim Integrated 8 MAX9025-MAX9028 UCSP, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference Functional Diagrams VCC VCC IN+ IN+ OUT IN- OUT IN- MAX9027 MAX9028 MAX9025 MAX9026 REF REF 1.236V VEE VEE Pin Description PIN MAX9025/ MAX9026 MAX9027/ MAX9028 NAME FUNCTION A2 A2 OUT Comparator Output A3 A3, B2 VEE Negative Supply Voltage B1 B1 IN+ Comparator Noninverting Input B2 -- REF 1.236V Reference Output A1 A1 VCC Positive Supply Voltage B3 B3 IN- Comparator Inverting Input Detailed Description The MAX9025/MAX9026 feature an on-board 1.236V 1% reference, yet draw an ultra-low supply current of 1.0A. The MAX9027/MAX9028 (without reference) consume just 0.6A of supply current. All four devices are guaranteed to operate down to +1.8V. Their common-mode input voltage range extends 200mV beyond-the-rails. Internal hysteresis ensures clean output switching, even with slow-moving input signals. Large internal output drivers allow rail-to-rail output swing with up to 5mA loads. The output stage employs a unique design that minimizes supply-current surges while switching, virtually eliminating the supply glitches typical of many other comparators. The MAX9025/MAX9027 have a push-pull output stage that sinks as well as sources current. The MAX9026/ www.maximintegrated.com MAX9028 have an open-drain output stage that can be pulled beyond VCC to a maximum of 5.5V above VEE. These open-drain versions are ideal for implementing wire-OR output logic functions. Input Stage Circuitry The input common-mode voltage range extends from VEE - 0.2V to VCC + 0.2V. These comparators operate at any differential input voltage within these limits. Input bias current is typically 0.15nA if the input voltage is between the supply rails. Comparator inputs are protected from overvoltage by internal ESD protection diodes connected to the supply rails. As the input voltage exceeds the supply rails, these ESD protection diodes become forward biased and begin to conduct. Output Stage Circuitry The MAX9025-MAX9028 contain a unique break-beforemake output stage capable of rail-to-rail operation with up to 5mA loads. Many comparators consume orders of magnitude more current during switching than during steady-state operation. However, with this family of comparators, the supply-current change during an output transition is extremely small. In the Typical Operating Characteristics, the Supply Current vs. Output Transition Frequency graphs show the minimal supply-current increase as the output switching frequency approaches 1kHz. This characteristic reduces the need for powersupply filter capacitors to reduce glitches created by comparator switching currents. In battery-powered applications, this characteristic results in a substantial increase in battery life. Maxim Integrated 9 MAX9025-MAX9028 UCSP, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference Reference (MAX9025/MAX9026) The MAX9025-MAX9028s' internal +1.236V reference has a typical temperature coefficient of 40ppm/C over the full -40C to +85C temperature range. The reference is a very-low-power bandgap cell, with a typical 35k output impedance. REF can source and sink up to 100nA to external circuitry. For applications needing increased drive, buffer REF with a low input-bias current op amp such as the MAX4162. Most applications require no REF bypass capacitor. For noisy environments or fast VCC transients, connect a 1nF to 10nF ceramic capacitor from REF to GND. Applications Information Low-Voltage, Low-Power Operation The MAX9025-MAX9028 are ideally suited for use with most battery-powered systems. Table 1 lists a variety of battery types, capacities, and approximate operating times for the MAX9025-MAX9028, assuming nominal conditions. Internal Hysteresis Many comparators oscillate in the linear region of operation because of noise or undesired parasitic feedback. This tends to occur when the voltage on one input is equal or very close to the voltage on the other input. The MAX9025-MAX9028 have internal 4mV hysteresis to counter parasitic effects and noise. The hysteresis in a comparator creates two trip points: one for the rising input voltage (VTHR) and one for the falling input voltage (VTHF) (Figure 2). The difference between the trip points is the hysteresis (VHB). When the comparator's input voltages are equal, the hysteresis VCC BANDGAP REF VEE Figure 1. MAX9025/MAX9026 Voltage Reference Output Equivalent Circuit effectively causes one comparator input to move quickly past the other, thus taking the input out of the region where oscillation occurs. Figure 2 illustrates the case in which IN- has a fixed voltage applied, and IN+ is varied. If the inputs were reversed, the figure would be the same, except with an inverted output. Adding External Hysteresis In applications requiring more than the internal 4mV hysteresis of the MAX9025-MAX9028, additional hysteresis can be added with external components. Because the MAX9025-MAX9028 are intended for very low-power systems, care should be taken to minimize power dissipation in the additional circuitry. Regardless of which approach is taken, the external hysteresis will be VCC dependent. Over the full discharge range of battery-powered systems, the hysteresis can change as much as 40%. This must be considered during design. Table 1. Battery Applications Using MAX9025-MAX9028 BATTERY TYPE RECHARGEABLE VFRESH (V) VEND-OF-LIFE (V) CAPACITY, AA SIZE (mA-h) MAX9025/MAX9026 OPERATING TIME (hr) MAX9027/MAX9028 OPERATING TIME (hr) Alkaline (2 Cells) No 3.0 1.8 2000 1.8 x 106 2.8 x 106 N i c k e l Cadmium (2 Cells) Yes 2.4 1.8 750 680,000 1.07 x 106 Lithium-Ion (1 Cell) Yes 3.5 2.7 1000 0.9 x 106 1.4 x 106 Nickel-MetalHydride (2 Cells) Yes 2.4 1.8 1000 0.9 x 106 1.4 x 106 www.maximintegrated.com Maxim Integrated 10 MAX9025-MAX9028 UCSP, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference THRESHOLDS IN+ VTHR HYSTERESIS IN- VHB VIN RFB RS VCC BAND VTHF MAX9027 OUT VCC/2 OUT Figure 2. Threshold Hysteresis Band Figure 3. MAX9025/MAX9027 External Hysteresis Simplest Circuit Asymmetrical Hysteresis The simplest circuit for adding external hysteresis is shown in Figure 3. In this example, the hysteresis is defined by: When the input threshold is not set at 1/2 VCC, the hysteresis added to the input threshold will not be symmetrical. This is typical of the MAX9025/MAX9026 where the internal reference is usually used as the threshold. If the asymmetry is unacceptable, it can be corrected by adding resistors to the circuit. Hysteresis = RS x VCC R FB where RS is the source resistance and RFB is the feedback resistance. Because the comparison threshold is 1/2 VCC, the MAX9027 was chosen for its push-pull output and lack of reference. This provides symmetrical hysteresis around the threshold. Output Considerations In most cases, the push-pull outputs of the MAX9025/ MAX9027 are best for external hysteresis. The opendrain output of the MAX9026/MAX9028 can be used, but the effect of the feedback network on the actual output high voltage must be considered. Component Selection Because the MAX9025-MAX9028 are intended for very low power-supply systems, the highest impedance circuits should be used wherever possible. The offset error due to input-bias current is proportional to the total impedance seen at the input. For example, selecting components for Figure 3, with a target of 50mV hysteresis, a 5V supply, and choosing an RFB of 10M gives RS as 100k. The total impedance seen at IN+ is therefore 10M || 100k, or 99k. The maximum IB of the MAX9025-MAX9028 is 2nA; therefore, the error due to source impedance is less than 400V. www.maximintegrated.com Board Layout and Bypassing Power-supply bypass capacitors are not typically needed, but use 100nF bypass capacitors close to the device's supply pins when supply impedance is high, supply leads are long, or excessive noise is expected on the supply lines. Minimize signal trace lengths to reduce stray capacitance. A ground plane and surface-mount components are recommended. If the REF pin is decoupled, use a new low-leakage capacitor. Zero-Crossing Detector Figure 4 shows a zero-crossing detector application. The MAX9027's inverting input is connected to ground, and its noninverting input is connected to a 100mVP-P signal source. As the signal at the noninverting input crosses 0V, the comparator's output changes state. Logic-Level Translator The Typical Application Circuit shows an application that converts 5V logic to 3V logic levels. The MAX9028 is powered by the +5V supply voltage, and the pullup resistor for the MAX9028's open-drain output is connected to the +3V supply voltage. This configuration allows the full 5V logic swing without creating overvoltage on the 3V logic inputs. For 3V to 5V logic-level translations, simply connect the +3V supply voltage to VCC and the +5V supply voltage to the pullup resistor. Maxim Integrated 11 MAX9025-MAX9028 UCSP, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference Typical Application Circuit VCC VCC 100mVP-P +5V (+3V) IN+ +3V (+5V) OUT IN- 2M MAX9027 VEE VCC RPULLUP IN- 3V (5V) LOGIC OUT OUT 2M IN+ MAX9028 Figure 4. Zero-Crossing Detector UCSP Applications Information For the latest application details on UCSP construction, dimensions, tape carrier information, printed circuit board techniques, bump-pad layout, and recommended reflow temperature profiles, as well as the latest information on reliability testing results, go to Application Note 1891: Wafer-Level Packaging (WLP) and its Applications. VEE 5V (3V) LOGIC IN LOGIC-LEVEL TRANSLATOR Chip Information PROCESS: BiCMOS Package Information For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a "+", "#", or "-" in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. www.maximintegrated.com PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO. 6 UCSP B6+1 21-0097 Refer to Application Note 1891 Maxim Integrated 12 MAX9025-MAX9028 UCSP, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference Revision History REVISION NUMBER REVISION DATE 0 5/04 Initial release -- 1 6/11 Added information for lead-free versions 1 DESCRIPTION PAGES CHANGED For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated's website at www.maximintegrated.com. Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance. Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc. (c) 2011 Maxim Integrated Products, Inc. 13