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MAX6791TPLD2+-MAX6791TPSD2+-MAX6791TPSD2+T-MAX6793TPLD2+-MAX6794TPLD3+-MAX6795TPLD2+-MAX6795TPLD2+T
High-Voltage, Micropower, Single/Dual Linear Regulators with Supervisory Functions
General DescriptionThe MAX6791–MAX6796 ultra-low-quiescent-current,
single-/dual-output linear regulators are ideal for auto-
motive applications. The devices offer a wide 5V to 72V
operating input range, allowing them to withstand auto-
motive load-dump conditions while consuming only
68µA. The MAX6791–MAX6794 are dual-output regula-
tors capable of supplying up to 150mA per output. The
MAX6795/MAX6796 offer a single output capable of
delivering up to 300mA. These devices offer standard
output-voltage options (5V, 3.3V, 2.5V, or 1.8V) and can
be adjusted to any voltage from 1.8V to 11V. The
MAX6791–MAX6794 also offer a fixed 5V output.
All devices feature a push-pull or open-drain, active-low
RESEToutput with a fixed output reset threshold that is
92.5%/87.5% of the regulator output OUT/OUT1. The
reset output asserts low when OUT/OUT1 drops below
the reset threshold and remains low for the fixed or
capacitor-adjustable reset timeout period after
OUT/OUT1 exceeds the reset threshold.
The MAX6791–MAX6796 provide a watchdog input that
monitors a pulse train from the microprocessor (µP) and
generates reset pulses if the watchdog input remains
high or low for a duration longer than the watchdog
timeout period. All devices are available with either a
fixed watchdog timeout period of 280ms (min) or a peri-
od adjustable with an external capacitor. The
MAX6791/MAX6792 feature a windowed watchdog
timeout period with selectable window ratio. The watch-
dog feature can be disabled.
The MAX6791–MAX6794 provide dual enable inputs
(ENABLE1 and ENABLE2) that control each regulator
independently. The single-output MAX6795/MAX6796
feature one enable input (ENABLE).
All devices include a hold input (HOLD)that aids the
implementation of a self-holding circuit without requir-
ing external components. Once the regulator is
enabled, setting HOLDlow forces the regulator to
remain on even if ENABLE/ENABLE1 is subsequently
set low. Releasing HOLDshuts down the regulator.
The MAX6791–MAX6796 are available in a small, ther-
mally enhanced TQFN package. The 5mm x 5mm
package dissipates up to 2.7W, supporting continuous
regulator operation during high ambient temperatures,
high battery voltage, and high load-current conditions.
The MAX6791–MAX6796 are specified for a -40°C to
+125°C operating temperature range.
Applications
FeaturesLow 68µA Quiescent Current Wide 5V to 72V Supply Voltage RangeOutput Current
Single Output Up to 300mA
Dual Outputs Up to 150mA per OutputLow Dropout Voltage420mV (typ) at 100mA (Single)
840mV (typ) at 100mA (Dual)Fixed Output-Voltage Options: 5V, 3.3V, 2.5V,
1.8V, or Adjustable Output (from 1.8V to 11V)ENABLE and HOLD FunctionalityRESET
Output: Open Drain or Push-PullInternally Fixed (35µs, 3.125ms, 12.5ms, 50ms, or
200ms) or Capacitor-Adjustable Reset Timeout
PeriodsInternally Fixed or Capacitor-AdjustableWatchdog Timeout PeriodsWindowed (Minimum/Maximum) Watchdog TimerOptions (MAX6791/MAX6792)Watchdog Disable FeatureThermal, Short-Circuit, and Output OvervoltageProtectionFully Specified from -40°C to +125°CSmall, Thermally Enhanced, 5mm x 5mm TQFN
MAX6791–MAX6796
High-Voltage, Micropower, Single/Dual
Linear Regulators with Supervisory Functions
Ordering Information19-3875; Rev 2; 10/11
+Denotes lead-free package.
For tape-and-reel, add a T after the “+.” Tape-and-reel are
offered in 2.5k increments. The first placeholder “_” designates
preset output-voltage option and preset reset threshold level;
see Table 1. The second placeholder “_ ” designates the reset
timeout period; see Table 2. For example, the MAX6791TPSD3+
indicates a 3.3V output voltage with a reset threshold of 87.5%
at nominal voltage and a 50ms reset timeout period. Samples
are generally held in stock. Nonstandard versions require a 2.5k
minimum order quantity.
/V Denotes an automotive-qualified part.
*EP = Exposed pad.
EVALUATION KIT
AVAILABLE
PARTTEMP RANGEPIN-PACKAGEA X6 7 9 1 TP _D _+ -40°C to +125°C20 TQFN-EP*
A X6 7 9 2 TP _D _+ -40°C to +125°C20 TQFN-EP*
A X6 7 9 3 TP _ D _+ -40°C to +125°C20 TQFN-EP*
A X6 7 9 4 TP _ D _+ -40°C to +125°C20 TQFN-EP*
A X6 7 9 5 TP _ D _+ -40°C to +125°C20 TQFN-EP*AX 6795TP _D _/V + -40°C to +125°C20 TQFN-EP*AX 6795TP S D 2/V + -40°C to +125°C20 TQFN-EP*
A X6 7 9 6 TP _D _+ -40°C to +125°C20 TQFN-EP*
MAX6791–MAX6796
High-Voltage, Micropower, Single/Dual Linear
Regulators with Supervisory Functions
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VIN= 14V, CIN= 1µF, COUT = 10µF, TA= TJ= -40°C to +125°C, unless otherwise noted. Typical values are at TA= TJ= +25°C.)
(Note 1)
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.
(All pins referenced to GND, unless otherwise noted.)
IN to GND...............................................................-0.3V to +80V
ENABLE, ENABLE1, ENABLE2, PFI,
GATEP to GND.........................................-0.3V to (VIN+ 0.3V)
GATEP to IN...........................................................-12V to +0.3V
OUT, OUT1, OUT2, PFO, RESET(open-drain versions),
CSRT, CSWT.......................................................-0.3V to +12VHOLD, RESET(push-pull versions), WDI, WDS0, WDS1,
WD-DIS, SET, SET1......................-0.3V to (VOUT/OUT1+ 0.3V)
OUT, OUT1, OUT2 Short Circuit to GND.....................Continuous
Maximum Current (all pins except IN and OUT_)...............50mA
Continuous Power Dissipation (TA= +70°C)
20-Pin TQFN (derate 33.3mW/°C above +70°C).....2666.7mW
Operating Temperature Range (TA)..................-40°C to +125°C
Junction Temperature (TJ).................................................150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C
Soldering Temperature (reflow).......................................+260°C
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS Supply Voltage Range VIN 5 72 V
Regulators on (ILOAD = 0mA), VIN = 8V 68 85
VIN = 8V, ILOAD = 300mA
(MAX6795/MAX6796) 130 220
VIN = 14V, ILOAD = 100mA
(MAX6795/MAX6796) 100160
VIN = 8V, ILOAD1 = ILOAD2
= 150mA
(MAX6791–MAX6794)
130 220
Regulators on,
VOUT/OUT1 =
VOUT2 = 5V
VIN = 14V, ILOAD1 =
ILOAD2 = 50mA
(MAX6791–MAX6794)
100160
Regulators on (ILOAD = 0mA), VIN = 42V 74 95
Supply Current IIN
Regulators on (ILOAD = 20mA, total)
OUT1/OUT2/OUT = 5V, VIN= 42V 100 170
µA
Shutdown Supply Current ISHDN Regulators off, VIN= 14V 27 45 µA
MAX6791–MAX6796
High-Voltage, Micropower, Single/Dual Linear
Regulators with Supervisory Functions
ELECTRICAL CHARACTERISTICS (continued)(VIN= 14V, CIN= 1µF, COUT = 10µF, TA= TJ= -40°C to +125°C, unless otherwise noted. Typical values are at TA= TJ= +25°C.)
(Note 1)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS L/M, ILOAD = ILOAD1 = 1mA 4.858 4.974 5.090
L/M, ILOAD = 150mA (MAX6791–MAX6794),
VIN= 8V 4.811 4.945 5.078
L/M, ILOAD = 300mA (MAX6795/MAX6796),
VIN = 8V 4.850 5 5.150
T/S, ILOAD = ILOAD1 = 1mA 3.206 3.282 3.360
T/S, ILOAD = 150mA (MAX6791–MAX6794),
VIN= 6V 3.175 3.263 3.351
T/S, ILOAD = 300mA (MAX6795/MAX6796),
VIN= 6V 3.201 3.3 3.399
Z/Y, ILOAD = ILOAD1 = 1mA 2.429 2.487 2.546
Z/Y, ILOAD = 150mA (MAX6791–MAX6794),
VIN= 5.5V 2.405 2.472 2.539
Z/Y, ILOAD = 300mA (MAX6795/MAX6796),
VIN= 5.5V 2.425 2.5 2.575
W/V, ILOAD = ILOAD1 = 1mA 1.748 1.791 1.832
W/V, ILOAD = 150mA (MAX6791–MAX6794),
VIN= 5V 1.731 1.780 1.828
Output Voltage VOUT/
VOUT1
W/V, ILOAD = 300mA (MAX6795/MAX6796),
VIN= 5V 1.746 1.8 1.854
ILOAD2 = 1mA 4.858 4.974 5.090 Output Voltage
(MAX6791–MAX6794) VOUT2 ILOAD2 = 150mA 4.811 4.945 5.079 V
SET/SET1 Threshold Voltage VSET ILOAD = ILOAD1 = 1mA, VOUT/OUT1 = 5V 1.207 1.2315 1.256 V
Adjustable Output Voltage VOUT 1.8 11.0 V
SET/SET1 rising 124 Dual-Mode™ SET Threshold
SET/SET1 falling 62
mV
SET/SET1 Input Current SET/SET1 = 1V, VIN = 11V -100 +100 nA
L/M, ILOAD = 20mA (Note 2) 84 130
L/M, ILOAD = 300mA (Note 2) 1200 1800 (MAX6795/
MAX6796)
T/S, ILOAD = 300mA (Note 3) 1700 2400
L/M, ILOAD = 150mA (Note 2) 1000 1800
L/M, ILOAD = 10mA (Note 2) 84 130
Dropout Voltage VDO
(MAX6791–
MAX6794)
T/S, ILOAD = 150mA (Note 3) 1700 2400
mV
MAX6795/MAX6796, inferred from dropout test 300 Guaranteed Output Current
(Note 4) MAX6791–MAX6794, inferred from dropout test 150 mA
Dual Mode is a trademark of Maxim Integrated Products, Inc.
MAX6791–MAX6796
High-Voltage, Micropower, Single/Dual Linear
Regulators with Supervisory Functions
ELECTRICAL CHARACTERISTICS (continued)(VIN= 14V, CIN= 1µF, COUT = 10µF, TA= TJ= -40°C to +125°C, unless otherwise noted. Typical values are at TA= TJ= +25°C.)
(Note 1)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS MAX6795/MAX6796, output shorted,
VIN = 6V 400 480
Short-Circuit Output Current Limit
(Note 4) MAX6791–MAX6794, output shorted,
VIN = 6V 200 240
mA
Thermal-Shutdown Temperature +165 °C
Thermal-Shutdown Hysteresis 20 °C
8V VIN 72V, ILOAD = 1mA 1 Line Regulation 8V VIN 72V, ILOAD = 10mA 1
% of
VOUT
IOUT = 1mA to 300mA
(MAX6795/MAX6796) 2
Load Regulation (Note 5)
IOUT = 1mA to 150mA
(MAX6791–MAX6794) 1.5
Power-Supply Rejection Ratio PSRR ILOAD = 10mA, f = 100Hz, VIN = 500mVP-P 69 dB
ILOAD = 300mA, VOUT = 5V,
VOUT = 90% of its nominal value 180
Startup Response Time tSTART
ILOAD = 150mA, VOUT = 5V,
VOUT1/OUT2 = 90% of its nominal value 360
µs
Output Overvoltage Protection
Threshold OVTH ISINK = 1mA from OUT/OUT1/OUT2 1.05 x
VOUT
1.1 x
VOUTV
Output Overvoltage Protection
Sink Current VOUT = VOUT (nominal) x 1.15 5 10 mA
IN to GATEP Clamp Voltage IGATEP = -100µA, VIN = 20V 13.8 16.3 18.8 V
IN to GATEP Drive Voltage IGATEP = 0A, VIN = 20V 8 10 12 V
ENABLE/ENABLE1/ENABLE2/
HOLD Input-Voltage Low VIL 0.4 V
ENABLE/ENABLE1/ENABLE2/
HOLD Input-Voltage High VIH 1.4 V
ENABLE/ENABLE1/ENABLE2
Input Pulldown Current Enable is internally pulled down to GND 0.5 µA
HOLD Input Pullup Current HOLD is internally pulled to OUT/OUT1 2 µA
MAX6791–MAX6796
High-Voltage, Micropower, Single/Dual Linear
Regulators with Supervisory Functions
ELECTRICAL CHARACTERISTICS (continued)(VIN= 14V, CIN= 1µF, COUT = 10µF, TA= TJ= -40°C to +125°C, unless otherwise noted. Typical values are at TA= TJ= +25°C.)
(Note 1)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
RESET OUTPUT 4.500 4.625 4.750 4.250 4.375 4.500 2.970 3.053 3.135 2.805 2.888 2.970 2.250 2.313 2.375 2.125 2.188 2.250 1.620 1.665 1.710
Reset Threshold (Preset Output
Voltage) SET/SET1 = GND 1.530 1.575 1.620
L/T/Z/W 0.90 x
VOUT
0.925 x
VOUT
0.95 x
VOUTReset Threshold (Adjustable
Output Voltage)
M/S/Y/V 0.85 x
VOUT
0.875 x
VOUT
0.90 x
VOUT
OUT to Reset Delay VOUT1/VOUT falling 35 µs
D0 35 µs
D1 2.187 3.125 4.063
D2 8.75 12.5 16.25
D3 35 50 65
Reset Timeout Period
(CSRT = OUT/OUT1) tRP VOUT1/VOUT rising
D4 140 200 260
ms
CSRT Ramp Current 800 1000 1250 nA
CSRT Ramp Threshold 1.185 1.218 1.255 V
WATCHDOG INPUT CSWT = OUT/OUT1 (fixed) 280.0 400.0 520.0 Normal Watchdog Timeout
Period tWD2CSWT = 1500pF (adjustable) 170 236.2 290 ms
CSWT = OUT/OUT1 (fixed) 37.5 50.0 62.5 Fast Watchdog Timeout Period
SET Ratio = 8 tWD1CSWT = 1500pF (adjustable) 21.95 29.52 36.90 ms
CSWT = OUT/OUT1 (fixed) 18.75 25.0 31.25 Fast Watchdog Timeout Period
SET Ratio = 16 tWD1CSWT = 1500pF (adjustable) 10.80 14.76 18.45 ms
CSWT = OUT/OUT1 (fixed) 4.68 6.25 7.81 Fast Watchdog Timeout Period
SET Ratio = 64 tWD1
CSWT = 1500pF (adjustable) 2.52 3.69 4.62
ms
Fast Watchdog Minimum Period tWD0 2000 ns
CSWT Ramp Current Adjustable timeout 800 1000 1250 nA
CSWT Ramp Threshold Adjustable timeout 1.185 1.218 1.255 V
Undercurrent Threshold for
Watchdog Enable 7.0 10 13.8 mA
Undercurrent Threshold for
Watchdog Disable 3 5 7 mA
MAX6791–MAX6796
High-Voltage, Micropower, Single/Dual Linear
Regulators with Supervisory Functions
ELECTRICAL CHARACTERISTICS (continued)(VIN= 14V, CIN= 1µF, COUT = 10µF, TA= TJ= -40°C to +125°C, unless otherwise noted. Typical values are at TA= TJ= +25°C.)
(Note 1)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
LOGIC INPUT (WDS0, WDS1, WD-DIS, WDI) Input-Voltage Low VIL 0.4 V
Input-Voltage High VIH 1.4 V
Input Current Inputs connected to OUT/OUT1 or GND -100 +100 nA
POWER-FAIL COMPARATORPFI Threshold VPFI 1.199 1.231 1.263 V
PFI Hysteresis 0.5 %
PFI Input Current VPFI = 14V -100 +100 nA
PFI to PFO Delay (VPFI + 50mV) to (VPFI - 50mV) 35 µs
LOGIC OUTPUT (RESET,PFO)
ISINK = 50µA (output asserted) 0.3 Output-Voltage Low (Open Drain
or Push-Pull) VOLISINK = 3.2mA (output asserted) 0.4 V
VOUT 1.0V, ISOURCE = 10µA (output not
asserted)
0.8 x
VOUT
VOUT 1.5V, ISOURCE = 100µA (output not
asserted)
0.8 x
VOUTOutput-Voltage High (Push-Pull) VOH
VOUT 2.2V, ISOURCE = 500µA (output not
asserted)
0.8 x
VOUT
Open-Drain Leakage V RESET = V PFO = 12V (output not asserted) 100 nA
Note 1:All devices are 100% production tested at TJ= +25°C and +125°C. Limits at -40°C are guaranteed by design.
Note 2:Dropout voltage is defined as (VIN- VOUT) when VOUTis 98% of VOUTfor VIN= 8V.
Note 3:Dropout voltage is defined as (VIN- VOUT) when VOUTis 98% of VOUTfor VIN= 6V.
Note 4:Operation beyond the absolute maximum power dissipation is not guaranteed and may damage the part.
Note 5:Test at VIN= 8V (L/M), VIN= 6V (T/S), VIN= 5V (Z/Y/W/V).
MAX6791–MAX6796
High-Voltage, Micropower, Single/Dual Linear
Regulators with Supervisory FunctionsSUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX6791-96 toc01
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (
MAX6791
NO LOAD
SUPPLY CURRENT vs. TEMPERATURE
MAX6791 toc02
TEMPERATURE (°C)
SUPPLY CURRENT (
ILOAD = 100mA
ILOAD = 50mA
ILOAD = 1mA
ILOAD = 0A
MAX6791
SHUTDOWN SUPPLY CURRENT
vs. SUPPLY VOLTAGE
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (
MAX6793/MAX6794
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
MAX6791toc04
TEMPERATURE (°C)
SHUTDOWN SUPPLY CURRENT (MAX6795
VIN = 14V
NORMALIZED RESET THRESHOLD
vs. TEMPERATURE
MAX6791toc05
TEMPERATURE (°C)
NORMALIZED RESET THRESHOLD
MAX6796
DROPOUT VOLTAGE
vs. TEMPERATURE
MAX6791toc06
TEMPERATURE (°C)
DROPOUT VOLTAGE (mV)
MAX6792
VOUT = 5V
ILOAD = 100mA
ILOAD = 150mA
ILOAD = 10mA
DROPOUT VOLTAGE
vs. TEMPERATURE
MAX6791toc07
DROPOUT VOLTAGE (mV)
MAX6796
ILOAD = 10mA
ILOAD = 150mA
ILOAD = 100mA
ILOAD = 300mA
OUTPUT VOLTAGE
vs. INPUT VOLTAGE
MAX6791-96toc08
OUTPUT VOLTAGE (V)
MAX6795
PRESET VOLTAGE,
NO LOAD
OUTPUT VOLTAGE vs. LOAD CURRENTMAX6791-96 toc09
OUT
(V)
MAX6796
VIN = 14V
VOUT = 5V
VOUT = 3.3V
SET EXTERNALLY
Typical Operating Characteristics(VIN= VEN= 14V, CIN= 0.1µF, COUT= 10µF, TJ= TA= +25°C, unless otherwise noted.)
Typical Operating Characteristics (continued)(VIN= VEN= 14V, CIN= 0.1µF, COUT= 10µF, TJ= TA= +25°C, unless otherwise noted.)
MAX6791–MAX6796
High-Voltage, Micropower, Single/Dual Linear
Regulators with Supervisory FunctionsNORMALIZED RESET TIMEOUT PERIOD
vs. TEMPERATURE
MAX6791toc10
TEMPERATURE (°C)
NORMALIZED RESET TIMEOUT PERIOD
MAX6796
-801001k100k
PSRR vs. FREQUENCYMAX6791toc11
FREQUENCY (Hz)
PSRR (dB)
10k
VIN = 6V
VOUT = 1.8V
ILOAD = 10mA
NORMALIZED WATCHDOG TIMEOUT PERIOD
vs. TEMPERATURE
MAX6791toc12
TEMPERATURE (°C)
NORMALIZED WATCHDOG TIMEOUT PERIOD
MAX6796
NORMALIZED PFI THRESHOLD
vs. TEMPERATURE
MAX6791toc13
TEMPERATURE (°C)
NORMALIZED PFI THRESHOLD
MAX6796
RESET OUTPUT
vs. SOURCE CURRENT
MAX6791-96toc14
RESET OUTPUT (V)
MAX6796
RESET OUTPUT VOLTAGE
vs. SINK CURRENTMAX6791-96toc15
RESET OUTPUT VOLTAGE (V)86723451
MAX6796
MAX6791–MAX6796
High-Voltage, Micropower, Single/Dual Linear
Regulators with Supervisory Functions
Typical Operating Characteristics (continued)(VIN= VEN= 14V, CIN= 0.1µF, COUT= 10µF, TJ= TA= +25°C, unless otherwise noted.)
10,000
RESET TIMEOUT PERIOD
vs. CCSRT
MAX6791-96toc16
CCSRT (μF)
RESET TIMEOUT PERIOD (ms)
WATCHDOG TIMEOUT PERIOD
vs. CCSWTMAX6791-96toc17
CCSWT (µF)
WATCHDOG TIMEOUT PERIOD
10,000
100,000
LOAD-TRANSIENT RESPONSE
MAX6791-96toc18
OUT1
IOUT1
100mA/div
1mA
1V/div
400μs/div
MAX6796
COUT = 10μF
VOUT = 5V
VIN = 14V
VOUT AC-
COUPLED
LOAD-TRANSIENT RESPONSEMAX6791-96toc19IOUT
OUT
100mA/div
1mA
500mV/div
400μs/div
OUT AC-
COUPLED
MAX6796
VIN = 14V
VOUT = 5V
LINE-TRANSIENT RESPONSEMAX6791-96toc20
VIN
OUT
10V/div
(AC-COUPLED)
20mV/div
1ms/div
OUT AC-
COUPLED
MAX6796
ILOAD = 10mA
MAX6791–MAX6796
High-Voltage, Micropower, Single/Dual Linear
Regulators with Supervisory Functions
Pin Description
Typical Operating Characteristics (continued)(VIN= VEN= 14V, CIN= 0.1µF, COUT= 10µF, TJ= TA= +25°C, unless otherwise noted.)
LOAD-TRANSIENT RESPONSEMAX6791-96toc21
OUT1
AC-COUPLED
IOUT1
100mA/div
1mA
500mV/div
1ms/div
MAX6792
VOUT1 = 5V
COUT = 10μF
LOAD-TRANSIENT RESPONSEMAX6791-96toc22
IOUT1
OUT1
AC-COUPLED
100mA/div
20mA
500mV/div
1ms/div
MAX6792
VOUT1 = 5V
COUT = 10μF
PIN
MAX6791/
MAX6792
MAX6793/
MAX6794
MAX6795/
MAX6796
NAMEFUNCTION 1, 2 1, 2 — OUT1
Regulator 1 Output. Fixed (+1.8V, +2.5V, +3.3V, or +5V) or adjustable (+1.8V
to +11V). VOUT1 = 150mA (max). Connect a 10µF (min) capacitor from OUT1
to GND.
3 3 — SET1
Feedback Input for Setting the OUT1 Voltage. Connect SET1 to GND to select
the preset output voltage. Connect to an external resistive divider for
adjustable output operation.
4 4 4 PFO
Active-Low, Open-Drain, Power-Fail Comparator Output. PFO asserts low
when PFI is below the internal 1.231V threshold. PFO deasserts when PFI is
above the internal 1.231V threshold.
5 5 5 CSWT
Watchdog Timeout Period Adjust Input. Connect CSWT to OUT1/OUT for the
internally fixed watchdog timeout period. For adjustable watchdog timeout
period, connect a capacitor from CSWT to GND. See the Selecting Watchdog
Timeout Period section for more details.
6 6 6 CSRT
Reset Timeout Period Adjust Input. Connect CSRT to OUT1/OUT for the
internally fixed timeout period. For adjustable timeout, connect a capacitor
from CSRT to GND. See the Reset Output section for more details.
7 7 7 GND Ground
8 8 8 RESET
Active-Low Reset Output. RESET remains low while OUT1/OUT is below the
reset threshold. RESET remains low for the duration of the reset timeout
period after the reset conditions end. RESET is available in push-pull and
open-drain options.
MAX6791–MAX6796
High-Voltage, Micropower, Single/Dual Linear
Regulators with Supervisory Functions
Pin Description (continued)
PIN
MAX6791/
MAX6792
MAX6793/
MAX6794
MAX6795/
MAX6796
NAMEFUNCTION 9 — — WDS1
10 — — WDS0
Min/Max Watchdog Logic-Select Input. WDS0 and WDS1 select the watchdog
window ratio or disable the watchdog timer. Drive WDS0 and WDS1 high or
low to select the desired ratio, see Table 4.
11 11 11 WDI
Watchdog Input.
MAX6793–MAX6796: A falling or rising transition must occur on WDI within the
selected watchdog timeout period or a reset pulse occurs. The watchdog timer
clears when a transition occurs on WDI or whenever RESET is asserted.
MAX6791/MAX6792: WDI falling and rising transitions within periods shorter
than tWD1 or longer than tWD2 force RESET to assert low for the reset timeout
period. The watchdog timer begins to count after RESET is deasserted. The
watchdog timer clears when a valid transition occurs on WDI or whenever
RESET is asserted. Connect WDS0 high and WDS1 low to disable the watchdog
timer function. See the Watchdog Timer section.
12 12 12 HOLD
Active-Low Regulator Hold Input. When HOLD is forced low, OUT1/OUT
remains ON even if ENABLE1/ENABLE is pulled low. To shut down the
output of the regulator (OUT/OUT1), release HOLD after ENABLE1/ENABLE is
pulled low. Connect HOLD to OUT1/OUT or leave unconnected if unused.
HOLD is internally connected to OUT/OUT1 through a 2µA current source.
13, 14 13, 14 — OUT2 Regulator 2 Output. OUT2 is a fixed +5V output. Connect a 10µF (min)
capacitor from OUT2 to GND.
15 15 — ENABLE2 Active-High Enable Input 2. Drive ENABLE2 high to turn on OUT2. ENABLE2
is internally connected to ground through a 0.5µA current sink.
16 16 16 PFI
Adjustable Power-Fail Comparator Input. Connect PFI to a resistive-divider to
set the desired PFI threshold. The PFI input is referenced to an accurate
1.231V threshold.
17, 18 17, 18 17, 18 IN Regulator Inputs. Bypass IN with a 1µF capacitor to GND.
19 19 19 GATEP pFET Gate Drive. Connect GATEP to the gate of a p-channel MOSFET to
provide low drop reverse-battery voltage protection.
20 20 — ENABLE1 Active-High Enable Input 1. Drive ENABLE1 high to turn on OUT1. ENABLE1
is internally connected to ground through a 0.5µA current sink.
— 9 9 WD-DIS
Watchdog Disable Input. Drive WD-DIS low to disable the watchdog timer.
Drive WD-DIS high or connect to OUT/OUT1 to enable the watchdog timer.
The watchdog timer clears when reset asserts.
MAX6791–MAX6796
High-Voltage, Micropower, Single/Dual Linear
Regulators with Supervisory Functions
Detailed DescriptionThe MAX6791–MAX6796 ultra-low-quiescent-current,
single-/dual-output, high-input-voltage linear regulators
operate from 5V to 72V. The MAX6791–MAX6794 fea-
ture dual regulators that deliver up to 150mA of load
current per output. One output is available with preset
output-voltage options (+1.8V, +2.5V, +3.3V, and
+5.0V) and can be adjusted to any voltage between
+1.8V to +11V using an external resistive-divider at
SET1. The other output provides a fixed 5V output volt-
age. The MAX6795/MAX6796 feature a single regulator
that delivers up to 300mA of current with preset output-
voltage options (+1.8V, +2.5V, +3.3V, and +5.0V) or
can be adjusted to any voltage between +1.8V to +11V.
All devices include an integrated µP reset circuit with a
fixed/adjustable reset and watchdog timeout period.
The MAX6791–MAX6796 monitor OUT/OUT1 and
assert a reset output when the output falls below the
reset threshold.
RegulatorsThe single and dual regulators accept an input voltage
from 5V to 72V. The MAX6791–MAX6796 offer fixed
preset output voltages of +1.8V, +2.5V, +3.3V, and
+5V, or an adjustable output voltage of +1.8V to +11V,
selected using an external resistive-divider network
connected between OUT1/OUT, SET1/SET, and GND
(see Figure 1). In addition to an adjustable output, the
MAX6791–MAX6794 feature a fixed 5V output voltage.
Reset OutputThe reset output is typically connected to the reset
input of a µP. A µP’s reset input starts or restarts the µP
in a known state. The MAX6791–MAX6796 supervisory
circuits provide the reset logic output to prevent code-
execution errors during power-up, power-down, and
brownout conditions (see the Typical Application
Circuit). RESETchanges from high to low whenever the
monitored output voltage drops below the reset thresh-
old voltage or the watchdog timeout expires. Once the
monitored voltage exceeds its respective reset thresh-
old voltage, RESETremains low for the reset timeout
period, then goes high.
Pin Description (continued)
PIN
MAX6791/
MAX6792
MAX6793/
MAX6794
MAX6795/
MAX6796
NAMEFUNCTION — 10 10, 13, 14, N.C. Not Internally Connected
— — 1, 2 OUT Regulator Output. Fixed +5V, +3.3V, +2.5V, +1.8V, or adjustable output
(+1.8V to +11V). Connect a 10µF (min) capacitor from OUT to GND.
— — 3 SET
Feedback Input for Setting the OUT Voltage. Connect SET to GND to select
the preset output voltage. Connect to an external resistive-divider for
adjustable output operation.
— — 20 ENABLE Active-High Enable Input. Drive ENABLE high to turn on the regulator.
ENABLE is internally connected to ground through a 0.5µA current sink.
— — — EP
Exposed Pad. EP is internally connected to GND. Connect EP to the ground
plane to provide a low thermal-resistance path from the IC junction to the PC
board. Do not use as the electrical connection to GND.
