19-3241; Rev 0; 5/04 UCSP, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference The MAX9025–MAX9028 nanopower comparators in space-saving chip-scale (UCSP™) packages feature Beyond-the-Rails™ inputs and are guaranteed to operate down to +1.8V. The MAX9025/MAX9026 feature an on-board 1.236V ±1% reference and draw an ultra-low supply current of only 1µA, while the MAX9027/ MAX9028 (without reference) require just 0.6µA 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 2-Cell Battery Monitoring/Management Ultra-Low-Power Systems Features ♦ Space-Saving UCSP Package (1mm x 1.52mm) ♦ Ultra-Low Supply Current 0.6µA (MAX9027/MAX9028) 1µA 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 -40°C to +85°C 6 UCSP-6 ADB MAX9026EBT-T -40°C to +85°C 6 UCSP-6 ADC MAX9027EBT-T -40°C to +85°C 6 UCSP-6 ADD MAX9028EBT-T -40°C to +85°C 6 UCSP-6 ADE Mobile Communications BUMPPACKAGE TOP MARK Pin Configurations Notebooks and PDAs TOP VIEW (BUMPS ON BOTTOM) Sensing at Ground or Supply Line B A IN+ VCC Telemetry and Remote Systems 1 Medical Instruments Selector Guide INTERNAL REFERENCE OUTPUT TYPE SUPPLY CURRENT (µA) MAX9025 Yes Push-Pull 1.0 MAX9026 Yes Open-Drain 1.0 MAX9027 No Push-Pull 0.6 MAX9028 No Open-Drain 0.6 PART Typical Application Circuit appears at end of data sheet. Beyond-the-Rails and UCSP are trademarks of Maxim Integrated Products, Inc. MAX9025– MAX9028 2 REF (VEE) OUT 3 IN- VEE ( ) MAX9027/MAX9028 PINS UCSP ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX9025–MAX9028 General Description 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 = +70°C) 6-Bump UCSP (derate 3.9mW/°C above +70°C)........308mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +150°C Bump Temperature (soldering) Reflow............................+235°C 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 = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER SYMBOL Supply Voltage Range VCC Supply Current ICC CONDITIONS Inferred from the PSRR test MIN VCC = 1.8V VCC = 5V 0.8 TA = +25°C 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 2 tPD- VEE 0.2 UNITS 5.5 V 1.5 1.7 VCC + 0.2 0.3 TA = TMIN to TMAX 5 10 4 0.15 MAX9025, VCC = 5V, ISOURCE = 6mA TA = +25°C MAX9025, VCC = 1.8V, ISOURCE = 1mA TA = +25°C 0.1 1 250 350 56 200 TA = TMIN to TMAX 450 TA = TMIN to TMAX VCC = 5V, ISINK = 6mA TA = +25°C VCC = 1.8V, ISINK = 1mA TA = +25°C 250 350 57 200 450 TA = TMIN to TMAX VCC = 5V mV nA mV/V mV mV 300 0.001 1 µA 35 VCC = 1.8V 3 VCC = 5V 33 VCC = 1.8V V 300 TA = TMIN to TMAX MAX9026 only, VO = 5.5V µA mV 1 2 VCC = 1.8V to 5.5V ISC MAX 2.2 TA = TMIN to TMAX Sinking, VO = VCC High-to-Low Propagation Delay (Note 4) TA = +25°C TA = +25°C Sourcing, VO = VEE Output Short-Circuit Current 1.0 TA = TMIN to TMAX IN+ Voltage Range Input Bias Current TYP 1.8 mA 3 VCC = 1.8V 7 VCC = 5V 6 _______________________________________________________________________________________ µs UCSP, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference MAX9025–MAX9028 ELECTRICAL CHARACTERISTICS—MAX9025/MAX9026 (WITH REF) (continued) (VCC = +5V, VEE = 0V, VIN+ = VREF, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN VCC = 1.8V MAX9025 only TYP MAX UNITS 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 µs Fall Time tFALL CL = 15pF 0.2 µs Power-Up Time MAX9026 only, RPULLUP = 100kΩ VCC = 5V 31 tON Reference Voltage VREF Reference Voltage Temperature Coefficient TCREF Reference Output Voltage Noise EN µs 1.2 TA = +25°C 1.224 TA = TMIN to TMAX 1.205 1.236 ms 1.248 1.267 ppm/ °C 40 CREF = 1nF BW = 10Hz to 100kHz 29 BW = 10Hz to 6kHz 60 V µVRMS Reference Line Regulation ∆VREF/ ∆VCC VCC = 1.8V to 5.5V 0.5 mV/V Reference Load Regulation ∆VREF/ ∆IOUT ∆IOUT = 0nA to 100nA 0.03 mV/ nA ELECTRICAL CHARACTERISTICS—MAX9027/MAX9028 (WITHOUT REF) (VCC = +5V, VEE = 0V, VCM = 0V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER SYMBOL Supply Voltage Range VCC Supply Current ICC CONDITIONS Inferred from the PSRR test MIN VCC = 1.8V VCC = 5V 0.45 TA = +25°C VCM Inferred from the CMRR test Input Offset Voltage VOS -0.2V ≤ VCM ≤ (VCC + 0.2V) (Note 2) Input Bias Current VHB IB 0.6 TA = TMIN to TMAX Input Common-Mode Voltage Range Input-Referred Hysteresis TYP 1.8 TA = +25°C MAX UNITS 5.5 V 0.75 1.0 µA 1.25 VEE 0.2 VCC + 0.2 0.3 V 5 mV TA = TMIN to TMAX -0.2V ≤ VCM ≤ (VCC + 0.2V) (Note 3) TA = +25°C 10 4 0.15 TA = TMIN to TMAX 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 _______________________________________________________________________________________ 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 = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER Output Voltage Swing High Output Voltage Swing Low Output Leakage Current SYMBOL VCC - VOH VOL ILEAK CONDITIONS MAX9027 only, VCC = 5V, ISOURCE = 5mA TA = +25°C MAX9028 only, VCC = 1.8V, ISOURCE = 1mA TA = +25°C VCC = 5V, ISINK = 5mA TA = +25°C VCC = 1.8V, ISINK = 1mA TA = +25°C 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 TA = TMIN to TMAX 500 58 TA = TMIN to TMAX 191 mV 400 500 56 TA = TMIN to TMAX VCC = 5V 200 UNITS 300 TA = TMIN to TMAX MAX9028 only, VO = 5.5V Sourcing, VO = VEE Output Short-Circuit Current MIN 200 mV 300 0.001 1 µA 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 = 100kΩ 16 VCC = 5V, RPULLUP = 100kΩ 45 mA µs µs Rise Time tRISE MAX9027 only, CL = 15pF 1.6 µs Fall Time tFALL CL = 15pF 0.2 µs 1.2 ms Power-Up Time tON 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 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. 4 _______________________________________________________________________________________ UCSP, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference MAX9027/MAX9028 SUPPLY CURRENT vs. SUPPLY VOLTAGE TA = +25°C TA = -40°C 800 TA = +85°C 600 500 TA = +25°C 2.5 1.5 3.5 4.5 4.5 5.5 -40 -15 10 35 60 SUPPLY VOLTAGE (V) TEMPERATURE (°C) MAX9027/MAX9028 SUPPLY CURRENT vs. TEMPERATURE MAX9025/MAX9026 SUPPLY CURRENT vs. OUTPUT TRANSITION FREQUENCY MAX9027/MAX9028 SUPPLY CURRENT vs. OUTPUT TRANSITION FREQUENCY VCC = 3V VCC = 3V 25 20 15 VCC = 5V 10 400 VCC = 1.8V -15 10 35 60 85 25 VCC = 3V 20 15 VCC = 5V 5 0 VCC = 1.8V 0 1 0.1 10 100 0.1 1 100 10 TEMPERATURE (°C) TRANSITION FREQUENCY (kHz) TRANSITION FREQUENCY (kHz) OUTPUT VOLTAGE LOW vs. SINK CURRENT OUTPUT VOLTAGE LOW vs. SINK CURRENT MAX9025/MAX9027 OUTPUT VOLTAGE HIGH vs. SOURCE CURRENT VCC = 3V VCC = 1.8V 400 200 VCC = 5V 600 TA = +25°C 400 TA = +85°C 200 TA = -40°C 0 0 2 4 6 SINK CURRENT (mA) 8 10 800 MAX9025-28 toc09 600 800 MAX9025-28 toc08 MAX9025-28 toc07 800 OUTPUT VOLTAGE LOW (mV) -40 30 10 5 300 35 VCC = 1.8V 85 MAX9025-28 toc06 30 SUPPLY CURRENT (µA) 600 500 35 SUPPLY CURRENT (µA) VCC = 5V 40 MAX9025-28 toc05 40 MAX9025-28 toc04 700 SUPPLY CURRENT (nA) 3.5 SUPPLY VOLTAGE (V) 800 0 800 600 2.5 1.5 5.5 VCC = 3V VCC = 1.8V 300 600 VCC = 5V 1000 TA = -40°C 400 OUTPUT VOLTAGE LOW (mV) MAX9025-28 toc02 700 SUPPLY CURRENT (nA) 1000 1200 OUTPUT VOLTAGE HIGH (VCC - VOH, mV) SUPPLY CURRENT (nA) TA = +85°C 800 SUPPLY CURRENT (nA) MAX9025-28 toc01 1200 MAX9025/MAX9026 SUPPLY CURRENT vs. TEMPERATURE MAX9025-28 toc03 MAX9025/MAX9026 SUPPLY CURRENT vs. SUPPLY VOLTAGE 600 VCC = 1.8V VCC = 3V 400 200 VCC = 5V 0 0 2 4 6 SINK CURRENT (mA) 8 10 0 2 4 6 8 10 SOURCE CURRENT (mA) _______________________________________________________________________________________ 5 MAX9025–MAX9028 Typical Operating Characteristics (VCC = +5V, VEE = 0V, CL = 15pF, VOVERDRIVE = 100mV, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (VCC = +5V, VEE = 0V, CL = 15pF, VOVERDRIVE = 100mV, TA = +25°C, unless otherwise noted.) TA = +85°C 200 TA = -40°C TA = +25°C 0 VCC = 5V 20 VCC = 3V 10 VCC = 1.8V VOUT = VEE 0 4 6 8 10 VCC = 5V 20 VCC = 3V 10 VCC = 1.8V -15 10 35 60 85 -40 -15 10 35 60 TEMPERATURE (°C) OFFSET VOLTAGE vs. TEMPERATURE HYSTERESIS VOLTAGE vs. TEMPERATURE INPUT BIAS CURRENT vs. INPUT BIAS VOLTAGE MAX9025-28 toc13 0.8 VCC = 1.8V VCC = 3V 0.3 4.0 VCC = 3V VCC = 1.8V 3.5 3.0 VCC = 5V 2.5 1.000 85 MAX9025-28 toc15 TEMPERATURE (°C) MAX9025-28 toc14 SOURCE CURRENT (mA) 1.0 0.5 30 0 -40 INPUT BIAS CURRENT (IN-) (nA) 2 HYSTERESIS VOLTAGE (mV) 0 OFFSET VOLTAGE (mV) 30 40 SHORT-CIRCUIT SINK CURRENT (mA) 400 VOUT = VCC MAX9025-28 toc11 600 MAX9025/MAX9027 SHORT-CIRCUIT SOURCE CURRENT vs. TEMPERATURE 40 SHORT-CIRCUIT SINK CURRENT (mA) MAX9025-28 toc10 OUTPUT VOLTAGE HIGH (VCC - VOH, mV) 800 SHORT-CIRCUIT SINK CURRENT vs. TEMPERATURE MAX9025-28 toc12 MAX9025/MAX9027 OUTPUT VOLTAGE HIGH vs. SOURCE CURRENT IN+ = 2.5V 0.600 0.200 -0.200 -0.600 VCC = 5V 2.0 0 -40 -15 10 35 60 -15 10 35 60 85 -0.5 0.5 1.5 2.5 3.5 4.5 INPUT BIAS VOLTAGE (IN-) (V) MAX9025/MAX9026 REFERENCE VOLTAGE vs. TEMPERATURE MAX9025/MAX9026 REFERENCE VOLTAGE vs. TEMPERATURE MAX9025/MAX9026 REFERENCE VOLTAGE vs. SUPPLY VOLTAGE 1.2340 1.237 1.235 1.233 -40 -15 10 35 TEMPERATURE (°C) 60 85 1.237 1.236 1.235 1.234 1.231 1.2330 1.238 5.5 MAX9025-28 toc18 MAX9025-28 toc17 5 DEVICES REFERENCE VOLTAGE (V) VCC = 5V 1.2350 1.239 REFERENCE VOLTAGE (V) VCC = 1.8V 1.2360 MAX9025-28 toc16 TEMPERATURE (°C) VCC = 3V 6 -1.000 -40 85 TEMPERATURE (°C) 1.2370 REFERENCE VOLTAGE (V) MAX9025–MAX9028 UCSP, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference -40 -15 10 35 TEMPERATURE (°C) 60 85 1.5 2.5 3.5 SUPPLY VOLTAGE (V) _______________________________________________________________________________________ 4.5 5.5 UCSP, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference MAX9025/MAX9026 REFERENCE VOLTAGE vs. REFERENCE CURRENT 1.238 VCC = 1.8V 15 40 VCC = 5V tPD- (µs) 1.236 VCC = 5V tPD+ (µs) VCC = 3V VCC = 1.8V 10 30 VCC = 3V 20 VCC = 5V 1.234 MAX9025-28 toc21 VCC = 3V 50 MAX9025-28 toc20 20 MAX9025-28 toc19 1.240 REFERENCE VOLTAGE (V) MAX9025/MAX9027 PROPAGATION DELAY (tPD+) vs. TEMPERATURE PROPAGATION DELAY (tPD-) vs. TEMPERATURE 5 10 VCC = 1.8V 1.232 0 -50 -100 0 50 100 0 -40 -15 10 35 85 -15 10 35 60 TEMPERATURE (°C) PROPAGATION DELAY (tPD-) vs. CAPACITIVE LOAD MAX9025/MAX9027 PROPAGATION DELAY (tPD+) vs. CAPACITIVE LOAD PROPAGATION DELAY (tPD-) vs. INPUT OVERDRIVE 30 10 VCC = 3V 20 VCC = 5V VCC = 1.8V 0 40 VCC = 3V 10 100 VCC = 5V 10 0 0 1 VCC = 1.8V 50 20 10 0.1 60 VCC = 3V 30 5 0.01 70 tPD- (µs) tPD+ (µs) VCC = 5V MAX9025-28 toc24 VCC = 1.8V 0.01 0.1 1 10 100 0 10 20 30 40 CAPACITIVE LOAD (nF) 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) 50 175 150 tPD+ (µs) VCC = 5V 30 VCC = 3V 50 MAX9025 toc27 MAX9025-28 toc26 200 MAX9025-28 toc25 60 40 85 80 MAX9025-28 toc23 40 MAX9025-28 toc22 15 tPD+ (µs) -40 TEMPERATURE (°C) 20 tPD- (µs) 60 REFERENCE CURRENT (nA) +100mV IN+ -100mV 125 100 75 20 10 VCC = 1.8V 0 OUT 2V/div 50 VCC = 5V 25 VCC = 3V 0V VCC = 1.8V 0 0 10 20 30 INPUT OVERDRIVE (mV) 40 50 10 100 1000 10000 20µs/div PULLUP RESISTANCE (kΩ) _______________________________________________________________________________________ 7 MAX9025–MAX9028 Typical Operating Characteristics (continued) (VCC = +5V, VEE = 0V, CL = 15pF, VOVERDRIVE = 100mV, TA = +25°C, unless otherwise noted.) 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 = +25°C, unless otherwise noted.) 1kHz FREQUENCY RESPONSE (VCC = 5V) PROPAGATION DELAY (VCC = 1.8V) PROPAGATION DELAY (VCC = 3V) MAX9025 toc29 MAX9025 toc28 MAX9025 toc30 +100mV +100mV IN+ IN+ IN+ -100mV -100mV OUT 1V/div OUT 2V/div 0V 0V -100mV OUT 1V/div 0V 20µs/div 20µs/div 10kHz FREQUENCY RESPONSE (VCC = 1.8V) REFERENCE RESPONSE TO SUPPLY VOLTAGE TRANSIENT (CREF = 10nF) 200µs/div POWER-UP/POWER-DOWN RESPONSE MAX9025 toc32 MAX9025 toc31 +100mV 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 20µs/div 8 0V 1ms/div 40µs/div _______________________________________________________________________________________ UCSP, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference 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 MAX9026/MAX9028 have an open-drain output stage that can be pulled beyond VCC to a maximum of 5.5V above V EE. These open-drain versions are ideal for implementing wire-OR output logic functions. Input Stage Circuitry 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 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 Detailed Description The MAX9025/MAX9026 feature an on-board 1.236V ±1% reference, yet draw an ultra-low supply current of 1.0µA. The MAX9027/MAX9028 (without reference) consume just 0.6µA 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 The MAX9025–MAX9028 contain a unique breakbefore-make 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 power-supply filter capacitors to reduce glitches created by comparator switching currents. In battery-powered applications, this characteristic results in a substantial increase in battery life. _______________________________________________________________________________________ 9 MAX9025–MAX9028 Functional Diagrams MAX9025–MAX9028 UCSP, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference Reference (MAX9025/MAX9026) VCC The MAX9025–MAX9028s’ internal +1.236V reference has a typical temperature coefficient of 40ppm/°C over the full -40°C to +85°C temperature range. The reference is a very-low-power bandgap cell, with a typical 35kΩ 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 effectively causes one comparator input to move REF BANDGAP VEE Figure 1. MAX9025/MAX9026 Voltage Reference Output Equivalent Circuit 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 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 NickelCadmium (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 BATTERY TYPE 10 ______________________________________________________________________________________ UCSP, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference RFB RS VTHR VIN HYSTERESIS INVHB VCC BAND VTHF MAX9027 OUT VCC/2 OUT Figure 2. Threshold Hysteresis Band Figure 3. MAX9025/MAX9027 External Hysteresis Simplest Circuit The simplest circuit for adding external hysteresis is shown in Figure 3. In this example, the hysteresis is defined by: Asymmetrical Hysteresis 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 × VCC RFB 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 open-drain 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 10MΩ gives RS as 100kΩ. The total impedance seen at IN+ is therefore 10MΩ || 100kΩ, or 99kΩ. The maximum IB of the MAX9025–MAX9028 is 2nA; therefore, the error due to source impedance is less than 400µV. 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 surfacemount 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. ______________________________________________________________________________________ 11 MAX9025–MAX9028 THRESHOLDS IN+ MAX9025–MAX9028 UCSP, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference Typical Application Circuit VCC +5V (+3V) VCC 100mVP-P +3V (+5V) IN+ OUT 2MΩ IN- VCC RPULLUP IN- MAX9027 OUT 2MΩ VEE 3V (5V) LOGIC OUT 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 Maxim’s web site at www.maxim-ic.com/ucsp to find the Application Note: UCSP—A Wafer-Level Chip-Scale Package. 12 VEE 5V (3V) LOGIC IN LOGIC-LEVEL TRANSLATOR Chip Information TRANSISTOR COUNT: 209 PROCESS: BiCMOS ______________________________________________________________________________________ UCSP, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference 6L, UCSP.EPS PACKAGE OUTLINE, 3x2 UCSP 21-0097 G 1 1 Note: The MAX9025EBT–MAX9028EBT use Package Code B6-1. Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 13 © 2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. MAX9025–MAX9028 Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.)