19-2535; Rev 0; 7/02 Low-Power, Single-/Dual-Level Battery Monitors with Hysteresis and Integrated µP Reset Features ♦ Factory-Trimmed VBATT Threshold Options for Monitoring Single-Cell Li+ or Multicell Alkaline/NiCd/NiMH Applications ♦ Immune to Short Battery Voltage Transients ♦ Low Current (2.5µA typ at 3.6V) ♦ Single and Dual Low-Battery Output Options ♦ 150ms Minimum LBO Timeout Period ♦ Independent µP Reset with Manual Reset ♦ Factory-Set Reset Thresholds for Monitoring VCC from 1.8V to 3.3V ♦ Available with 150ms (min) and 1.2s (min) VCC Reset Timeout Period Options ♦ -40°C to +85°C Operating Temperature Range ♦ Small 6- and 8-Pin SOT23 Packages ♦ No External Components Ordering Information PART TEMP RANGE PIN-PACKAGE MAX6439UT_ _ _D_-T -40°C to +85°C 6 SOT23-6 MAX6440UT_ _ _D_-T -40°C to +85°C 6 SOT23-6 MAX6441KA_ _ _D_-T -40°C to +85°C 8 SOT23-8 MAX6442KA_ _ _D_-T -40°C to +85°C 8 SOT23-8 Note: The first two “_ _” are placeholders for the battery monitor voltage levels. Desired threshold levels are set by the part number suffix found in Tables 1 and 2. The third “_” is the VCC reset threshold level suffix found in Table 3. The “_” after the D is a placeholder for the reset timeout period suffix found in Table 4. All devices are available in tape-and-reel only. There is a 2500-piece minimum order increment for standard versions. Sample stock is typically held on standard versions only. Nonstandard versions require a minimum order increment of 10,000 pieces. Contact factory for availability. Pin Configurations Applications Battery-Powered Systems (Single-Cell Li+ or Two-/Three-Cell NiMH, NiCd, Alkaline) TOP VIEW VBATT 1 6 VCC 5 GND 4 RESET Cell Phones/Cordless Phones Portable Medical Devices MR 2 MAX6439 MAX6440 Electronic Toys Pagers LBO 3 PDAs MP3 Players SOT23-6 Pin Configurations continued at end of data sheet. ________________________________________________________________ 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 MAX6439–MAX6442 General Description The MAX6439–MAX6442 are a family of ultra-low-power battery monitors with integrated microprocessor (µP) supervisors. The battery monitors are offered with single or dual low-battery output options that can be used to signal when the battery is OK (enabling full system operation), when the battery is low (for low-power system operation), and when the battery is dead (to disable system operation). These devices also have an independent µP supervisor that monitors VCC and provides an active-low reset output. A manual reset function is available to reset the µP with a push-button. No external components are required. The MAX6439–MAX6442 are offered with several factory-trimmed low-battery threshold combinations ideal for single-cell lithium-ion (Li+) or multicell alkaline/NiCd/ NiMH applications. When the battery voltage drops below each specified low threshold, the low-battery outputs are asserted to alert the system. When the voltage rises above the specified high thresholds, the outputs are deasserted after a 150ms minimum timeout period, ensuring the voltages have stabilized before power circuitry is activated or providing microprocessor reset timing. The low and high thresholds provide hysteresis in battery-operated systems to eliminate output chattering. The MAX6439/MAX6440 offer factory-trimmed battery monitors with a single output. The MAX6441/MAX6442 offer factory-trimmed battery monitors with dual outputs. All battery monitors have open-drain low-battery outputs. The MAX6439–MAX6442 monitor system voltages (VCC) from 1.8V to 3.3V with seven fixed reset threshold options. Each device is offered with two minimum reset timeout periods of 150ms or 1200ms. The MAX6439/ MAX6441 are offered with an open-drain RESET output and the MAX6440/MAX6442 are offered with a pushpull RESET output. The MAX6439–MAX6442 are offered in a SOT23 package and are fully specified over a -40°C to +85°C temperature range. MAX6439–MAX6442 Low-Power, Single-/Dual-Level Battery Monitors with Hysteresis and Integrated µP Reset ABSOLUTE MAXIMUM RATINGS VBATT, VCC to GND.................................................-0.3V to +6V* Open-Drain LBO, LBOH, LBOL, LBOLH to GND ...-0.3V to +6V* Open-Drain RESET to GND ....................................-0.3V to +6V* Push-Pull RESET to GND............................-0.3V to (VCC + 0.3V) MR to GND .................................................-0.3V to (VCC + 0.3V) Input/Output Current, All Pins .............................................20mA Continuous Power Dissipation (TA = +70°C) 6-Pin SOT23 (derate 8.7mW/°C above +70°C)............695mW 8-Pin SOT23 (derate 8.9mW/°C above +70°C)............714mW 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°C *Applying 7V for a duration of 1ms does not damage the device. 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 (VBATT = 1.2V to 5.5V, VCC = 1.2V to 5.5V, TA = -40°C to +85°C, unless otherwise specified. Typical values are at TA = +25°C.) (Note1) PARAMETER SYMBOL VBATT Operating Voltage Range VBATT VCC Operating Voltage Range VCC + VBATT Supply Current VCC CONDITIONS MIN TYP MAX TA = 0°C to +85°C 1.0 5.5 TA = -40°C to +85°C 1.2 5.5 TA = 0°C to +85°C 1.0 5.5 TA = -40°C to +85°C 1.2 5.5 ICC + IBATT VBATT = 3.6V, VCC = 3.3V, no load (Note 2) 2.5 7 UNITS V V µA VBATT THRESHOLDS HTH Threshold LTH Threshold 2 HTH LTH MAX6439UT_ J, MAX6440UT_ J 3.510 3.60 3.690 MAX6439UT_ I, MAX6440UT_ I 3.413 3.50 3.588 MAX6439UT_ H, MAX6440UT_ H 3.315 3.40 3.485 MAX6439UT_ G, MAX6440UT_ G 3.218 3.30 3.383 MAX6439UT_ T, MAX6440UT_ T 2.535 2.60 2.665 MAX6439UT_ S, MAX6440UT_ S 2.438 2.50 2.563 MAX6439UT_ R, MAX6440UT_ R 2.340 2.40 2.460 MAX6439UT_ Q, MAX6440UT_ Q 2.243 2.30 2.358 MAX6439UTF, MAX6440UTF 3.023 3.10 3.178 MAX6439UTE, MAX6440UTE 2.925 3.00 3.075 MAX6439UTD, MAX6440UTD 2.828 2.90 2.973 MAX6439UTC, MAX6440UTC 2.730 2.80 2.870 MAX6439UTB, MAX6440UTB 2.633 2.70 2.768 MAX6439UTA, MAX6440UTA 2.535 2.60 2.665 MAX6439UTP, MAX6440UTP 2.048 2.10 2.153 MAX6439UTO, MAX6440UTO 1.950 2.00 2.050 MAX6439UTN, MAX6440UTN 1.853 1.90 1.948 MAX6439UTM, MAX6440UTM 1.755 1.80 1.845 MAX6439UTL, MAX6440UTL 1.658 1.70 1.743 MAX6439UTK, MAX6440UTK 1.560 1.60 1.640 _______________________________________________________________________________________ V V Low-Power, Single-/Dual-Level Battery Monitors with Hysteresis and Integrated µP Reset (VBATT = 1.2V to 5.5V, VCC = 1.2V to 5.5V, TA = -40°C to +85°C, unless otherwise specified. Typical values are at TA = +25°C.) (Note1) PARAMETER HTH- Threshold HTH+ Threshold LTH- Threshold LTH+ Threshold SYMBOL HTH- HTH+ LTH- LTH+ MIN TYP MAX MAX6441UT_ J, MAX6442UT_ J CONDITIONS 3.510 3.600 3.690 MAX6441UT_ I, MAX6442UT_ I 3.413 3.500 3.588 MAX6441UT_ H, MAX6442UT_ H 3.315 3.400 3.485 MAX6441UT_ G, MAX6442UT_ G 3.218 3.300 3.383 MAX6441UT_ T, MAX6442UT_ T 2.535 2.600 2.665 MAX6441UT_ S, MAX6442UT_ S 2.438 2.500 2.563 MAX6441UT_ R, MAX6442UT_ R 2.340 2.400 2.460 MAX6441UT_ Q, MAX6442UT_ Q 2.243 2.300 2.358 MAX6441UT_ J, MAX6442UT_ J 3.686 3.780 3.875 MAX6441UT_ I, MAX6442UT_ I 3.583 3.675 3.767 MAX6441UT_ H, MAX6442UT_ H 3.481 3.570 3.659 MAX6441UT_ G, MAX6442UT_ G 3.378 3.465 3.552 MAX6441UT_ T, MAX6442UT_ T 2.662 2.730 2.798 MAX6441UT_ S, MAX6442UT_ S 2.559 2.625 2.691 MAX6441UT_ R, MAX6442UT_ R 2.457 2.520 2.583 MAX6441UT_ Q, MAX6442UT_ Q 2.355 2.415 2.476 MAX6441UTF, MAX6442UTF 3.023 3.100 3.178 MAX6441UTE, MAX6442UTE 2.925 3.000 3.075 MAX6441UTD, MAX6442UTD 2.828 2.900 2.973 MAX6441UTC, MAX6442UTC 2.730 2.800 2.870 MAX6441UTB, MAX6442UTB 2.633 2.700 2.768 MAX6441UTA, MAX6442UTA 2.535 2.600 2.665 MAX6441UTP, MAX6442UTP 2.048 2.100 2.153 MAX6441UTO, MAX6442UTO 1.950 2.000 2.050 MAX6441UTN, MAX6442UTN 1.853 1.900 1.948 MAX6441UTM, MAX6442UTM 1.755 1.800 1.845 1.743 MAX6441UTL, MAX6442UTL 1.658 1.700 MAX6441UTK, MAX6442UTK 1.560 1.600 1.640 MAX6441UTF, MAX6442UTF 3.174 3.255 3.337 MAX6441UTE, MAX6442UTE 3.071 3.150 3.229 MAX6441UTD, MAX6442UTD 2.969 3.045 3.121 MAX6441UTC, MAX6442UTC 2.867 2.940 3.014 MAX6441UTB, MAX6442UTB 2.764 2.835 2.906 MAX6441UTA, MAX6442UTA 2.662 2.730 2.798 MAX6441UTP, MAX6442UTP 2.150 2.205 2.260 MAX6441UTO, MAX6442UTO 2.048 2.100 2.153 MAX6441UTN, MAX6442UTN 1.945 1.995 2.045 MAX6441UTM, MAX6442UTM 1.843 1.890 1.937 MAX6441UTL, MAX6442UTL 1.740 1.785 1.830 MAX6441UTK, MAX6442UTK 1.638 1.680 1.722 UNITS V V V V _______________________________________________________________________________________ 3 MAX6439–MAX6442 ELECTRICAL CHARACTERISTICS (continued) MAX6439–MAX6442 Low-Power, Single-/Dual-Level Battery Monitors with Hysteresis and Integrated µP Reset ELECTRICAL CHARACTERISTICS (continued) (VBATT = 1.2V to 5.5V, VCC = 1.2V to 5.5V, TA = -40°C to +85°C, unless otherwise specified. Typical values are at TA = +25°C.) (Note1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 150 225 300 ms LBO, LBOL, LBOH, LBOLH Timeout Period tLBOP VBATT rising above threshold LBO, LBOL, LBOH, LBOLH Delay Time tLBOD VBATT falling below threshold LBO, LBOL, LBOH, LBOLH Output Low (Open Drain) LBO, LBOL, LBOH, LBOLH Output Open-Drain Leakage Current VCC Reset Threshold VOL ILKG VTH 100 (VBATT or VCC) ≥ 1.2V, ISINK = 50µA, asserted low 0.3 (VBATT or VCC) ≥ 1.6V, ISINK = 100µA, asserted low 0.3 (VBATT or VCC) ≥ 2.7V, ISINK = 1.2mA, asserted low 0.3 (VBATT or VCC) ≥ 4.5V, ISINK = 3.2mA, asserted low 0.3 Output deasserted 500 V MAX64_ _ _ _ _ _ T 3.000 3.075 3.150 MAX64_ _ _ _ _ _ S 2.850 2.925 3.000 MAX64_ _ _ _ _ _ R 2.550 2.625 2.700 MAX64_ _ _ _ _ _ Z 2.250 2.313 2.375 MAX64_ _ _ _ _ _ Y 2.125 2.188 2.250 MAX64_ _ _ _ _ _ W 1.620 1.665 1.710 MAX64_ _ _ _ _ _ V 1.530 1.575 1.620 VCC Reset Hysteresis VCC falling at 10mV/µs from (VTH + 100mV) to (VTH - 100mV) VCC to RESET Delay VCC to RESET Timeout Period MR Input Voltage MR Minimum Pulse Width tRP 225 300 1800 2400 VIL 0.3 x VCC 0.7 x VCC 1 tDEB V ns 200 tMRP ms µs 100 MR Pullup Resistance 4 µs 150 MR to RESET Delay MR Rising Debounce Period 50 1200 tMPW V % MAX64_ _ _ _ _ _ _ D7 VIH nA 0.3 MAX64_ _ _ _ _ _ _ D3 MR Glitch Rejection MR Reset Timeout Period µs ns 150 225 300 MR to VCC 750 1500 2250 Ω (Note 3) 150 225 300 ms _______________________________________________________________________________________ ms Low-Power, Single-/Dual-Level Battery Monitors with Hysteresis and Integrated µP Reset (VBATT = 1.2V to 5.5V, VCC = 1.2V to 5.5V, TA = -40°C to +85°C, unless otherwise specified. Typical values are at TA = +25°C.) (Note1) PARAMETER SYMBOL CONDITIONS MIN VCC ≥ 1.53V, ISOURCE = 100µA, RESET deasserted RESET Output High (Push-Pull) VOH RESET Output Low RESET Output Leakage Current (Open Drain) MAX UNITS 0.8 x VCC V VCC ≥ 2.55V, ISOURCE = 500µA, RESET deasserted VOL TYP 0.8 x VCC VCC ≥ 1.0V, ISINK = 50µA, RESET asserted 0.3 VCC ≥ 1.2V, ISINK = 100µA, RESET asserted 0.3 VCC ≥ 2.12V, ISINK = 1.2mA, RESET asserted 0.3 RESET deasserted 500 V nA Note 1: Production testing done at TA = +25°C; limits over temperature guaranteed by design only. Note 2: The device is powered up by the highest voltage between VBATT and VCC. Note 3: MR input ignores falling input pulses, which occur within the MR debounce period (tDEB) after a valid MR reset assertion. This prevents invalid reset assertion due to switch bounce. Typical Operating Characteristics (VBATT = 1.2V to 5.5V, VCC = 1.2V to 5.5V, unless otherwise specified. Typical values are at TA = +25°C.) TOTAL 2 IBATT 1 ICC 0 1.05 1.00 0.95 0.90 -40 -20 0 20 40 TEMPERATURE (°C) 60 80 NORMALIZED RESET TIMEOUT PERIOD vs. TEMPERATURE 1.015 MAX6439 toc03 MAX6439 toc02 MAX6439 toc01 3 1.10 NORMALIZED LBO TIMEOUT PERIOD SUPPLY CURRENT (µA) 4 NORMALIZED LBO TIMEOUT PERIOD vs. TEMPERATURE NORMALIZED RESET TIMEOUT PERIOD SUPPLY CURRENT vs. TEMPERATURE VCC = 3.3V, VBATT = 3.6V 1.010 1.005 1.000 0.995 0.990 0.985 0.980 -40 -20 0 20 40 TEMPERATURE (°C) 60 80 -40 -20 0 20 40 60 80 TEMPERATURE (°C) _______________________________________________________________________________________ 5 MAX6439–MAX6442 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (continued) (VBATT = 1.2V to 5.5V, VCC = 1.2V to 5.5V, unless otherwise specified. Typical values are at TA = +25°C.) LBO ASSERTS ABOVE THIS LINE 100 90 80 70 60 55 50 RESET ASSERTS ABOVE THIS LINE 45 40 35 30 1.050 100 1000 LOWER TRIP VOLTAGE 1.000 UPPER TRIP VOLTAGE 0.975 0.950 10 100 LTH THRESHOLD OVERDRIVE (mV) -40 1000 -20 0 VTH THRESHOLD OVERDRIVE (mV) 20 40 TEMPERATURE (°C) LBO OUTPUT vs. SINK CURRENT VCC = 3.3V, VBATT = 2.1V NORMALIZED RESET THRESHOLD vs. TEMPERATURE MAX6439 toc08 120 MAX6439 toc07 1.050 100 1.025 LBO OUTPUT (mV) NORMALIZED RESET THRESHOLD 1.025 25 20 10 MAX6439 toc06 MAXIMUM VCC TRANSIENT DURATION (µs) 110 NORMALIZED UPPER (HTH) AND LOWER (LTH) TRIP VOLTAGES vs. TEMPERATURE MAX6439 toc05 60 MAX6439 toc04 120 MAXIMUM VCC TRANSIENT DURATION vs. VTH THRESHOLD OVERDRIVE NORMALIZED TRIP VOLTAGES MAXIMUM VBATT TRANSIENT DURATION vs. LTH THRESHOLD OVERDRIVE MAXIMUM VBATT TRANSIENT DURATION (µs) 1.000 80 60 40 0.975 20 LBO ASSERTED 0 0.950 -40 -20 0 20 40 60 2 0 80 4 TEMPERATURE (°C) 6 8 10 ISINK (mA) RESET OUTPUT vs. SINK CURRENT VCC = 2.1V, VBATT = 3.6V RESET OUTPUT vs. SOURCE CURRENT VCC = 3.3V, VBATT = 3.6V 120 MAX6439 toc10 3.50 MAX6439 toc09 140 3.25 100 RESET OUTPUT (V) RESET OUTPUT (mV) MAX6439–MAX6442 Low-Power, Single-/Dual-Level Battery Monitors with Hysteresis and Integrated µP Reset 80 60 40 RESET ASSERTED 3.00 2.75 20 0 2.50 0 2 4 6 ISINK (mA) 6 8 10 0 0.5 1.0 1.5 2.0 2.5 3.0 ISOURCE (mA) _______________________________________________________________________________________ 3.5 60 80 Low-Power, Single-/Dual-Level Battery Monitors with Hysteresis and Integrated µP Reset PIN MAX6439/ MAX6440 MAX6441/ MAX6442 NAME FUNCTION 1 1 VBATT Battery Voltage Input. Input for battery voltage threshold monitors and device power supply if VBATT is greater than VCC. 2 3 MR Manual Reset Input, Active-Low, Internal 1.5kΩ Pullup to VCC. Pull low to assert a one-shot edge-triggered RESET output for the MR reset timeout period. Leave unconnected or connect to VCC if unused. The MR input is debounced for MR rising edges to prevent false reset events. 3 — LBO Low-Battery Output, Active Low, Open Drain. LBO is asserted when VBATT drops below the LTH specification and remains asserted until VBATT rises above the HTH specification for at least 150ms. Reset Output, Active Low, Push-Pull or Open Drain. RESET changes from high to low when the VCC input drops below the selected reset threshold and remains low for the VCC reset timeout period after VCC exceeds the reset threshold. RESET is one-shot edge-trigger pulsed low for the MR reset timeout period when the MR input is pulled low. RESET is an open-drain output for the MAX6439/MAX6441, and a push-pull output for the MAX6440/MAX6442. The push-pull outputs are referenced to VCC. RESET is guaranteed to be in the correct logic state for VBATT or VCC > 1.0V. 4 5 RESET 5 2 GND Ground 6 8 VCC VCC Voltage Input. Input for VCC reset threshold monitor and device power supply if VCC is greater than VBATT. — 6 LBOH Low-Battery Output High, Active Low, Open Drain. LBOH is asserted when VBATT drops below the HTH- specification. LBOH is deasserted when VBATT rises above the HTH+ specification for at least 150ms. — 7 LBOL Low-Battery Output Low, Active Low, Open Drain. LBOL is asserted when VBATT drops below the LTH- specification. LBOL is deasserted when VBATT rises above the LTH+ specification for at least 150ms. — 4 LBOLH Low-Battery Output Low/High, Active Low, Open Drain. LBOLH is asserted when VBATT drops below the LTH- specification. LBOLH is deasserted when VBATT rises above the HTH+ specification for at least 150ms. Detailed Description The MAX6439–MAX6442 family is available with several monitoring options. The factory-trimmed thresholds eliminate the requirement for external components. The MAX6439/MAX6440 have single low-battery outputs and the MAX6441/MAX6442 have dual low-battery outputs (see Figure 1a and Figure 1b). The MAX6439–MAX6442 combine a 1.23V reference with two comparators, logic, and timing circuitry to provide the user with information about the charge state of the power-supply batteries. The MAX6441/MAX6442 monitor separate high-voltage and low-voltage thresholds to determine battery status. The output(s) can be used to signal when the battery is charged, when the battery is low, and when the battery is empty. Factorytrimmed thresholds are ideal for monitoring single-cell Li+ or multicell alkaline/NiCd/NiMH power supplies. When the power-supply voltage drops below the specified low threshold, the low-battery output asserts. When the voltage rises above the specified high threshold following a 150ms (min) timeout period, the low-battery output is deasserted. This ensures the supply voltage _______________________________________________________________________________________ 7 MAX6439–MAX6442 Pin Description MAX6439–MAX6442 Low-Power, Single-/Dual-Level Battery Monitors with Hysteresis and Integrated µP Reset VBATT MAX6441 VBATT MAX6440 LTH DETECT LBOL 5% HYST LTH DETECT R Q S Q LBO TIMEOUT PERIOD LBOH LBO HTH DETECT LBO TIMEOUT PERIOD HTH DETECT 5% HYST LBOLH VCC 1.23V VCC VCC VTH DETECT RESET TIMEOUT PERIOD 1.23V RESET RESET VTH DETECT VCC RESET TIMEOUT PERIOD MR VCC MR Figure 1a. Functional Diagram Figure 1b. Functional Diagram has stabilized before power-converter or microprocessor activity is enabled. low-battery outputs: LBOH, LBOL, and LBOLH. LBOH asserts when VBATT drops below VHTH- and remains asserted for at least 150ms after VBATT rises above VHTH+. LBOL asserts when VBATT drops below VLTHand remains asserted for at least 150ms after VBATT rises above VLTH+. LBOLH asserts when VBATT drops below VLTH- and remains asserted for at least 150ms after VBATT rises above VHTH+ (see Figure 3). For fastrising VBATT input, the LBOL timeout period must complete before the LBOH/LBOLH timeout period begins. These devices also have an independent µP supervisor that monitors VCC and provides an active-low reset output. A manual reset function is available to allow the user to reset the µP with a push-button. Low-Battery Output The low-battery outputs are available in active-low (LBO, LBOL, LBOH, LBOLH), open-drain configurations. The low-battery outputs can be pulled to a voltage independent of VCC or VBATT, up to 5.5V. This allows the device to monitor and operate from direct battery voltage while interfacing to higher voltage microprocessors. The MAX6439/MAX6440 single-output voltage monitors provide a single low-battery output, LBO. These fixedthreshold devices assert LBO when VBATT drops below V LTH and remain asserted for at least 150ms after VBATT rises above VHTH (see Figure 2). The MAX6441/ MAX6442 triple-output voltage monitors provide three 8 Reset Output The MAX6439–MAX6442 provide an active-low reset output (RESET). RESET is asserted when the voltage at VCC falls below the reset threshold level. Reset remains asserted for the reset timeout period after VCC exceeds the threshold. If VCC goes below the reset threshold before the reset timeout period is completed, the internal timer restarts. The MAX6439/MAX6441 have opendrain reset outputs, while the MAX6440/MAX6442 have push-pull reset outputs (see Figure 4). _______________________________________________________________________________________ Low-Power, Single-/Dual-Level Battery Monitors with Hysteresis and Integrated µP Reset MAX6439–MAX6442 VBATT HTH LTH tLBOP LBO tLBOD tLBOP Figure 2. Single Low-Battery Output Timing HTH+ HTH- VBATT LTH+ LTH- LBOL tD tLBOP LBOH tLBOP tLBOP tD tLBOP LBOLH Figure 3. Dual Low-Battery Output Timing VCC VTH GND SWITCH BOUNCE MR SWITCH BOUNCE SWITCH BOUNCE SWITCH BOUNCE GND RESET tRP tMRP tMRP GND tDEB tMPW tDEB tMPW Figure 4. RESET Timing Diagram _______________________________________________________________________________________ 9 MAX6439–MAX6442 Low-Power, Single-/Dual-Level Battery Monitors with Hysteresis and Integrated µP Reset CURRENTLIMITED AC WALL ADAPTER VHTH VHYST VBATT DC/DC CONVERTER IN SHDN LED OUT GATE IN VLTH BATT CHG tLBOP MAX1879 PULSE-WIDTH SELECT INPUT LBO TSEL THERM 1-CELL Li+ BATTERY VCC VBATT LBOL MAX6441 MAX6442 GND LBOH LBOLH ADJ RESET HTH = BATTERY VOLTAGE GOOD, ENABLE OPERATION. LTH = BATTERY VOLTAGE LOW, SUSPEND/DISABLE OPERATION. GND THERMISTOR Figure 5. Hysteresis Figure 6. Li+ Charger Application (Using MAX1879) IN Li+ 3.6V DC/DC SHDN OUT LBOL VCC VBATT LBOH MAX6441 MAX6442 VCC NMI Hysteresis µP MR RESET GND logic levels, open-drain/open-collector outputs, or a momentary push-button switch to GND (the MR function is internally debounced for the tDEB timeout period) to create a manual reset function. If MR is driven from long cables, or if the device is used in a noisy environment, connect a 0.1µF capacitor from MR to GND to provide additional noise immunity (see Figure 4). RESET GND Hysteresis increases the comparator’s noise margin by increasing the upper threshold or decreasing the lower threshold. The hysteresis prevents the output from oscillating (chattering) when VBATT is near the low-battery threshold. This is especially important for applications where the load on the battery creates significant fluctuations in battery voltages (see Figure 5). Applications Information Li+ Battery Charger Application Figure 7. DC-to-DC Converter Application Manual Reset Many microprocessor-based products require manual reset capability, allowing the operator, a test technician, or external logic circuitry to initiate a reset while the monitored supplies remain above their reset thresholds. These devices have a dedicated active-low MR pin. When MR is pulled low, RESET asserts a one-shot low pulse for the MR reset timeout period. The MR input has an internal 1.5kΩ pullup resistor to VCC and can be left unconnected if not used. MR can be driven with CMOS- 10 The MAX6441/MAX6442 dual-output battery monitors can be used in conjunction with a battery charger to provide a system with additional information about the battery charge state. Many battery chargers, such as the MAX1879, provide the user with a CHG output, which tells the system when the battery is charged. The MAX6441/MAX6442 dual-output battery monitors provide three outputs, which can be used to relay the battery condition to the system. This information is useful in determining which system resources can be powered by the battery at the current charge state (see Figure 6). ______________________________________________________________________________________ Low-Power, Single-/Dual-Level Battery Monitors with Hysteresis and Integrated µP Reset VOLTAGES LOWER THRESHOLD (LTH) UPPER THRESHOLD (HTH) 3.3V 3.4V 3.5V 3.6V 2.6V AG AH AI AJ 2.7V BG BH BI BJ 2.8V CG CH CI CJ 2.9V DG DH DI DJ 3.0V EG EH EI EJ 3.1V FG FH FI FJ Table 2. Factory-Trimmed Lower and Upper Threshold Combinations for Two-Cell Alkaline/NiCd/NiMH Applications VOLTAGES LOWER THRESHOLD (LTH) UPPER THRESHOLD (HTH) 2.3V 2.4V 2.5V 2.6V 1.6V KQ KR KS KT 1.7V LQ LR LS LT 1.8V MQ MR MS MT 1.9V NQ NR NS NT 2.0V OQ OR OS OT 2.1V PQ PR PS PT Table 3. Factory-Trimmed VCC Reset Threshold Levels Table 4. VCC Reset Timeout Period Suffix Guide ACTIVE TIMEOUT PERIOD (ms) PART NO. SUFFIX (_) VCC NOMINAL RESET THRESHOLD (V) TIMEOUT PERIOD SUFFIX D3 150 300 T 3.075 D7 1200 2400 S 2.925 R 2.625 Z 2.313 Y 2.188 W 1.665 V 1.575 DC-to-DC Converter Application The MAX6441/MAX6442 triple-output battery monitors can be used in conjunction with a DC-to-DC converter to power microprocessor systems using a single Li+ cell or two to three alkaline/NiCd/NiMH cells. The LBOH output indicates that the battery voltage is weak, and is used to warn the microprocessor of potential problems. Armed with this information, the microprocessor can MIN MAX reduce system power consumption. The LBOL output indicates the battery is empty, and system power should be disabled. By connecting LBOL to the SHDN pin of the DC-to-DC converter, power to the microprocessor is removed. Microprocessor power does not return until the battery has recharged to a voltage greater than VLTH+ (see Figure 7). ______________________________________________________________________________________ 11 MAX6439–MAX6442 Table 1. Factory-Trimmed Lower and Upper Threshold Combinations for Single-Cell Li+ or Three-Cell Alkaline/NiCd/NiMH Applications MAX6439–MAX6442 Low-Power, Single-/Dual-Level Battery Monitors with Hysteresis and Integrated µP Reset Selector Guide OPEN-DRAIN RESET PUSH-PULL RESET SINGLE LOWBATTERY OUTPUT DUAL LOW-BATTERY OUTPUT MAX6439 X — X — MAX6440 — X X — MAX6441 X — — X MAX6442 — X — X PART Typical Application Circuit Standard Versions Table PART TOP MARK MAX6439UTDHRD3 ABMN MAX6439UTDHSD3 ABMO MAX6439UTEHRD3 ABMP MAX6439UTEHSD3 ABMQ MAX6439UTEIRD3 ABMR MAX6439UTEISD3 ABMS MAX6440UTDHRD3 ABMT MAX6440UTDHSD3 ABMU MAX6440UTEHRD3 ABMV MAX6440UTEHSD3 ABMW MAX6440UTEIRD3 ABMX MAX6440UTEISD3 ABMY DC/DC Li+ 3.6V VCC VCC LBO MR NMI µP MAX6439 MAX6440 VBATT RESET RESET GND MAX6441KADHRD3 AEEI MAX6441KADHSD3 AEEJ MAX6441KAEHRD3 AEEK MAX6441KAEHSD3 AEEL MAX6441KAEIRD3 AEEM MAX6441KAEISD3 AEEN MAX6442KADHRD3 AEEO GND MAX6442KADHSD3 AEEP MR MAX6442KAEHRD3 AEEQ MAX6442KAEHSD3 AEER MAX6442KAEIRD3 AEES MAX6442KAEISD3 AEET GND Pin Configurations (continued) TOP VIEW VBATT 1 2 3 MAX6441 MAX6442 LBOLH 4 8 VCC 7 LBOL 6 LBOH 5 RESET SOT23-8 Chip Information TRANSISTOR COUNT: 1478 PROCESS: BiCMOS 12 ______________________________________________________________________________________ Low-Power, Single-/Dual-Level Battery Monitors with Hysteresis and Integrated µP Reset 6LSOT.EPS ______________________________________________________________________________________ 13 MAX6439–MAX6442 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.) Package Information (continued) (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.) SOT23, 8L.EPS MAX6439–MAX6442 Low-Power, Single-/Dual-Level Battery Monitors with Hysteresis and Integrated µP Reset 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. 14 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.