General Description
The MAX5023/MAX5024 high-voltage linear regulators
operate from a +6.5V to +65V input voltage and deliver
up to 150mA of output current. These devices consume
only 60µA of quiescent current with no load and with-
stand a -60V reverse-battery voltage at the input. The
MAX5023/MAX5024 include an active-low internal
microprocessor (µP) reset circuit that asserts when the
regulator output drops below the preset output voltage
threshold by 7.5% or 12.5%, depending on the device
selected. Both devices are available with a fixed +3.3V
or +5V output. These devices are short-circuit protected
and include thermal shutdown.
In addition to an enable input to turn on or off the regu-
lator, the MAX5023/MAX5024 include a HOLD input
that allows for the implementation of a self-holding
circuit without requiring external components. Setting
HOLD low after enabling the regulator, forces the regu-
lator to remain on even if EN is subsequently set low.
Releasing HOLD shuts down the regulator.
The MAX5023 includes a watchdog input that monitors a
pulse train from the µP and generates reset pulses if the
watchdog input remains high or low for a duration longer
than the 1.6s watchdog timeout period. The MAX5024
includes a SET input which, when connected to ground,
selects a preset output voltage of +3.3V (MAX5024S/
MAX5024T) or +5V (MAX5024L/MAX5024M). Set the
adjustable output voltage by connecting SET to the regu-
lator’s output through a resistive-divider network.
The MAX5023/MAX5024 operate over the automotive
temperature range (-40°C to +125°C) and are available
in a thermally enhanced, surface-mount 8-pin SO-EP
package.
Applications
Automotive Fire/Smoke Alarms
Industrial Telecom/Networking
Home Security
Features
♦Wide Operating Input Voltage Range
+6.5V to +65V
♦Thermally Enhanced 8-Pin SO Package with
Exposed Pad Dissipates 1.5W
♦Guaranteed 150mA Output Current
♦60µA No-Load Supply Current
♦-60V Reverse-Battery Protection
♦Preset +3.3V or +5.0V Output Voltage
♦Thermal and Short-Circuit Protection
♦Operate Over -40°C to +125°C Temperature Range
♦Integrated µP Reset Circuit
♦Watchdog Timer with 1.6s Timeout Period
(MAX5023)
♦Regulator Enable and Hold Inputs Implement
Self-Holding Circuit
♦SET Input for Adjustable Output Voltage
(MAX5024)
MAX5023/MAX5024
65V, Low-Quiescent-Current, High-Voltage Linear
Regulators with µP Reset and Watchdog Timer
________________________________________________________________ Maxim Integrated Products 1
N.C.
HOLDRESET
1
2
8
7
OUT
WDIEN
GND
IN
SO-EP
TOP VIEW
3
4
6
5
MAX5023
N.C.
HOLDRESET
1
2
8
7
OUT
SETEN
GND
IN
SO-EP
3
4
6
5
MAX5024
PART TEMP RANGE PIN-PACKAGE
MAX5023_ ASA -40°C to +125°C 8 SO-EP*
MAX5024_ ASA -40°C to +125°C 8 SO-EP*
Pin Configurations
Ordering Information
19-2619; Rev 1; 2/04
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.
Selector Guide and Typical Operating Circuit appear at end
of data sheet.
Note: These parts offer a choice of reset thresholds, reset
threshold tolerances, and regulator output voltages. From the
Selector Guide, insert the desired suffix letter into the blank to
complete the part number.
*EP = Exposed Paddle.
MAX5023/MAX5024
65V, Low-Quiescent-Current, High-Voltage Linear
Regulators with µP Reset and Watchdog Timer
2_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VIN = +14V, IOUT = 1mA, CIN = 10µF, COUT = 15µF, VEN = +2.4V, HOLD = open, 10kΩfrom RESET to OUT, TA = -40°C to +125°C,
unless otherwise noted. Typical specifications are at TA = +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.
IN to GND................................................................-60V to +70V
EN to GND ...................................................-0.3V to (VIN + 0.3V)
HOLD to GND...........................................-0.3V to (VOUT + 0.3V)
SET, WDI, OUT to GND.......................................-0.3V to +13.2V
RESET to GND (Open Drain)...............................-0.3V to +13.2V
Short-Circuit Duration.................................................Continuous
Maximum Current to Any Pin (Except IN, OUT) ...............±20mA
Continuous Power Dissipation (TA= +70°C)
8-Pin SO-EP (derate 19.2mW/°C above +70°C) ........1538mW
Thermal Resistance:
(θJA).............................................................................52°C/W
(θJC)...............................................................................2°C/W
Operating Temperature Range .........................-40°C to +125°C
Junction Temperature......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Input Voltage Range VIN
VIN must be at least 1.5V greater than VOUT
6.5 65 V
Reverse Input Current
IREVERSE
VIN = -60V 0.1 10 µA
IOUT = 0mA 58 140
Supply Current IQ
M easur ed at G N D
IOU T
= 150m A
2000
µA
Shutdown Supply Current ISHDN VEN ≤ +0.4V 6 16 µA
REGULATOR
Guaranteed Output Current IOUT VOUT = +5V 150 mA
SET = GND, IOUT = 1mA to 150mA,
5V version 4.8 5 5.2
SET = GND, IOUT = 1mA to 150mA,
3.3V version
3.168
3.3
3.432
Output Voltage VOUT
IOUT = 5mA, adjustable version (MAX5024)
2.5 11
V
Dropout Voltage ∆VDO ILOAD = 150mA, VOUT = +5V (Note 2) 0.9 1.5 V
Startup Response Time Rising edge of VIN to VOUT, RL = 500Ω,
SET = GND 400 µs
+5V version -1 +1
Line Regulation ∆VOUT/
∆VIN +8V ≤ VIN ≤ +65V +3.3V version -0.5 0.5
mV/V
EN = high, regulator on 2.4
Enable Voltage VEN EN = low, regulator off 0.4 V
VEN = +2.4V 0.5
Enable Input Current IEN VEN = +14V 4 µA
HOLD Voltage VIL
Regulator on, EN transition from high to low
0.4 V
HOLD Release Voltage VIH EN = low, regulator shuts off VOUT -
0.4V
V
HOLD Pullup Current IHOLD Internally connected to OUT 4 µA
SET Reference Voltage VSET IOUT = 10mA
1.223 1.248 1.273
V
SET Input Leakage Current ISET 0.5 100 nA
MAX5023/MAX5024
65V, Low-Quiescent-Current, High-Voltage Linear
Regulators with µP Reset and Watchdog Timer
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VIN = +14V, IOUT = 1mA, CIN = 10µF, COUT = 15µF, VEN = +2.4V, HOLD = open, 10kΩfrom RESET to OUT, TA = -40°C to +125°C,
unless otherwise noted. Typical specifications are at TA = +25°C.) (Note 1)
Note 1: Limits at -40°C are guaranteed by characterization and not production tested.
Note 2: Dropout voltage is defined as VIN - VOUT when VOUT is 100mV below the value of VOUT for VIN = VOUT + 3V.
Note 3: VOUT = VSET (1 + R1 / R2) = 1.248V (1 + R1 / R2).
Note 4: RESET is guaranteed to be in the correct logic state for VOUT > +1V.
Note 5: Guaranteed by design, not production tested.
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Load Regulation ∆VOUT/
∆IOUT IOUT = 1mA to 150mA 1
mV/mA
PSRR IOUT = 10mA, f = 100Hz, 500mVP-P,
VOUT = +5V 54 dB
Short-Circuit Current ISC VIN = +8V 175 300 mA
Thermal-Shutdown
Temperature
TJ
(
SHDN
)
150 °C
∆TJ
(
SHDN
)
20 °C
RESET CIRCUIT
MAX502_L, SET = GND
4.50 4.625
4.75
MAX502_M, SET = GND
4.25 4.375
4.50
MAX502_T, SET = GND
2.970 3.052 3.135
MAX502_S, SET = GND
2.805 2.887 2.970
MAX5024L/T, SET = Divider
(Figure 1) (Note 3)
0.925 x
VOUT
Reset Threshold VTH
MAX5024M/S, SET = Divider
(Figure 1) (Note 3)
0.875 x
VOUT
V
Reset Timeout Period tRP 140 200 260 ms
VOUT to Reset Delay tRD VOUT falling 5 µs
VOUT ≥ +1.0V, ISINK = 50µA,
RESET asserted 0.3
VOUT ≥ +2.85V, ISINK = 1.2mA,
RESET asserted 0.3
Open-Drain RESET Output
Voltage (Note 4) VOL
VOUT ≥ +4.25V, ISINK = 3.2mA,
RESET asserted 0.4
V
Open-Drain RESET Output-
Leakage Current ILKG RESET not asserted, VRESET = +11V 1.0 µA
WATCHDOG FUNCTION
Watchdog Timeout Period tWD
1.12
1.6 2.08 s
WDI Pulse Width tWDI (Note 5) 50 ns
VIL 0.4
WDI Input Voltage VIH 2.4 V
WDI Input Current IWDI WDI = GND -1 +1 µA
MAX5023/MAX5024
65V, Low-Quiescent-Current, High-Voltage Linear
Regulators with µP Reset and Watchdog Timer
4_______________________________________________________________________________________
Typical Operating Characteristics
(VIN = +14V, CIN = 10µF, COUT = 15µF, VEN = +2.4V, VOUT = +5V, SET = GND, TA= +25°C, unless otherwise specified.)
OUTPUT VOLTAGE
vs. INPUT VOLTAGE
MAX5023 toc01
VIN (V)
VOUT (V)
605545 5015 20 25 30 35 405 10
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
0
065
IOUT = 0mA
NO-LOAD GROUND CURRENT
vs. TEMPERATURE
MAX5023 toc02
TEMPERATURE (°C)
IGND (µA)
1109565 80-10 5 20 35 50-25
10
20
30
40
50
60
70
80
90
100
0
-40 125
VIN = +6.5V
VIN = +14V
VIN = +65V
8
11
14
17
20
5
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
MAX5023 toc03
TEMPERATURE (°C)
ISHDN (µA)
1109565 80-10 5 20 35 50-25-40 125
4.80
4.85
4.90
4.95
5.00
5.05
5.10
5.15
5.20
5.25
4.75
OUTPUT VOLTAGE
vs. TEMPERATURE
MAX5023 toc04
TEMPERATURE (°C)
VOUT (V)
1109565 80-10 5 20 35 50-25-40 125
IOUT = 1mA
0.25
0.50
0.75
1.00
1.25
1.50
1.75
2.00
2.25
0
GROUND CURRENT
vs. TEMPERATURE
MAX5023 toc05
TEMPERATURE (°C)
IGND (mA)
1109565 80-10 5 20 35 50-25-40 125
ILOAD = 50mA
ILOAD = 150mA
ILOAD = 100mA
VOUT (V)
4.6
4.7
4.8
4.9
5.0
5.1
5.2
5.3
5.4
5.5
4.5
OUTPUT VOLTAGE
vs. LOAD CURRENT AND TEMPERATURE
MAX5023 toc06
TEMPERATURE (°C)
1109565 80-10 5 20 35 50-25-40 125
ILOAD = 50mA
ILOAD = 150mA
ILOAD = 100mA
DROPOUT VOLTAGE
vs. LOAD CURRENT
MAX5023 toc07
ILOAD (mA)
DROPOUT VOLTAGE (V)
13011070 905030
0.15
0.30
0.45
0.60
0.75
0.90
1.05
1.20
1.35
1.50
0
10 150
VOUT = 5V
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
MAX5023 toc08
FREQUENCY (kHz)
PSRR (dB)
100101
-70
-60
-50
-40
-30
-20
-10
0
-80
0.1 1000
COUT = 15µF
IOUT = 10mA
LOAD-TRANSIENT RESPONSE
MAX5023 toc09
200µs/div
VOUT
100mV/div
IOUT
100mA/div
MAX5023/MAX5024
65V, Low-Quiescent-Current, High-Voltage Linear
Regulators with µP Reset and Watchdog Timer
_______________________________________________________________________________________ 5
INPUT VOLTAGE STEP RESPONSE
MAX5023 toc10
200µs/div
VOUT
1V/div
5V
65V
6.5V
VIN
20V/div
VEN = VIN
IOUT = 1mA
STARTUP RESPONSE
MAX5023 toc11
200µs/div
VOUT
1V/div
5V
65V
0V
0V
VIN
50V/div
VEN = VIN
IOUT = 1mA
ENABLE STARTUP RESPONSE
(VIN = +14V)
MAX5023 toc12
100µs/div
VEN
1V/div
VOUT
2V/div
IOUT = 0mA
ENABLE STARTUP RESPONSE (VIN = +14V)
MAX5023 toc13
100µs/div
VEN
1V/div
VOUT
2V/div
IOUT = 150mA
ENABLE STARTUP RESPONSE (VIN = +65V)
MAX5023 toc14
100µs/div
VEN
1V/div
VOUT
2V/div
IOUT = 0mA
ENABLE STARTUP RESPONSE (VIN = +65V)
MAX5023 toc15
100µs/div
VEN
1V/div
VOUT
2V/div
IOUT = 150mA
Typical Operating Characteristics (continued)
(VIN = +14V, CIN = 10µF, COUT = 15µF, VEN = +2.4V, VOUT = +5V, SET = GND, TA= +25°C, unless otherwise specified.)
SHUTDOWN RESPONSE
MAX5023 toc16
40ms/div
VEN
1V/div
VOUT
2V/div
IOUT = 1mA
ENABLE AND HOLD TIMING
MAX5023 toc17
200ms/div
VEN
5V/div
VOUT
5V/div
VHOLD
5V/div
MAX5023/MAX5024
65V, Low-Quiescent-Current, High-Voltage Linear
Regulators with µP Reset and Watchdog Timer
6_______________________________________________________________________________________
0
10
5
20
15
25
30
47 5453 56 575548 5251 58 60 6159 80
GROUND-CURRENT DISTRIBUTION
(TA = +40°C)
MAX5023toc18
IGND (µA)
NUMBER OF UNITS
Typical Operating Characteristics (continued)
(VIN = +14V, CIN = 10µF, COUT = 15µF, VEN = +2.4V, VOUT = +5V, SET = GND, TA= +25°C, unless otherwise specified.)
0
10
5
20
15
25
30
45 5958 61 626053 5756 63 65 8964
GROUND-CURRENT DISTRIBUTION
(TA = +125°C)
MAX5023toc19
IGND (µA)
NUMBER OF UNITS
Pin Description
PIN
MAX5023
MAX5024
NAME FUNCTION
11IN
Regulator Input. Supply voltage ranges from +6.5V to +65V. Bypass with a 10µF capacitor to
GND.
22EN
Enable Input. Force EN high to turn on the regulator. Pull EN low and force HOLD high (or
open circuit) to place the device in shutdown mode. Internally connected to ground through a
5MΩ resistor.
33GND Ground. GND also functions as a heatsink. Solder to large pads or the circuit-board ground
plane to maximize thermal dissipation.
44RESET
Active-Low Open-Drain Reset Output. RESET remains low while VOUT is below the reset
threshold or when WDI is not pulsed within 1.6s. RESET remains low for the duration of the
reset timeout period after the reset conditions are terminated.
55HOLD
Regulator Hold Input. When HOLD is forced low, the regulator stores the on state of the
output allowing the regulator to function even if EN is pulled low. To shutdown the regulator,
release HOLD after EN is pulled low. If HOLD is unused, either float HOLD or connect to OUT.
Internally connected to OUT through a 4µA pullup current source (see Table 1, Truth Table).
66N.C. No Connection. Not internally connected.
7—WDI Watchdog Timer Input (MAX5023 only). The watchdog timer asserts a reset if WDI does not
transition within the 1.6s watchdog timeout period. WDI cannot be disabled.
88OUT Regulator Output. Fixed (+3.3V or +5V) or adjustable (+2.5V to +11V). Bypass with a 15µF
capacitor (min).
—7SET
Feedback Input for Setting the Output Voltage. Connect to GND to set the output voltage to
the preset fixed value (+3.3V or +5V). Connect to an external resistor-divider network for
adjustable output operation (MAX5024 only).
EP EP PAD Exposed Pad. Connect pad to GND.
Detailed Description
The MAX5023/MAX5024 high-voltage linear regulators
include an integrated µP reset circuit and watchdog
timer/adjustable output voltage. The devices guarantee
150mA load drive and are available with preset output
voltages of +3.3V or +5V. The MAX5023 features a
watchdog timer (WDI) with a 1.6s timeout period. The
MAX5024 offers an adjustable output voltage using an
external resistive-divider network between SET and
OUT. The internal reset circuit monitors the regulator
output voltage and asserts a reset output when the reg-
ulator output falls below the µP supply tolerance. Other
features include reverse-voltage protection to -60V,
enable (EN) and hold (HOLD) regulator control inputs,
16µA (max) shutdown current, short-circuit protection,
and thermal shutdown.
Regulator
The regulator accepts an input voltage range from
+6.5V to +65V. The MAX5023/MAX5024 offer fixed out-
put voltages of +3.3V and +5V. The MAX5024 also fea-
tures an adjustable output voltage that is implemented
with an external resistive-divider network connected
between OUT, SET, and GND (Figure 1). The MAX5024
automatically determines the feedback path depending
on the voltage at SET. Featured characteristics include
reverse-voltage protection to -60V and enable and hold
regulator control inputs. The Typical Operating Circuit
shows a self-holding configuration for the MAX5023.
MAX5023/MAX5024
65V, Low-Quiescent-Current, High-Voltage Linear
Regulators with µP Reset and Watchdog Timer
_______________________________________________________________________________________ 7
Functional Diagram
REVERSE BATTERY PROTECTION
CONTROL
LOGIC BANDGAP
REFERENCE
200ms
TIMEOUT
PERIOD
MUX
OUT
WATCHDOG
TIMER AND
LOGIC
RESET
THERMAL
SENSOR
CURRENT
SENSOR AND
REGULATOR
EN
HOLD
IN +6.5V to +65V
OUT
TO INTERNAL SHUTDOWN
CIRCUITRY
WDI*
*MAX5023 ONLY.
SET
(MAX5024 ONLY)
+2.5V to +11V
GND
R1
R2
4µA
AMP
COMP
Figure 1. Functional Diagram
MAX5023/MAX5024
Reset Output
The reset supervisor circuit is fully integrated in the
MAX5023/MAX5024 and uses the same reference volt-
age as the regulator. RESET asserts during power-
up/down and brownout conditions. RESET goes low if
VOUT drops below the preset output voltage threshold,
and remains low for 200ms (reset timeout period, tRP)
after VOUT rises above the reset voltage threshold. For
the MAX5023 only, RESET also asserts when WDI does
not transition for 1.6s (watchdog timeout period, tWD).
Two supply tolerance reset thresholds, -7.5% and
-12.5%, are available for each device type.
Watchdog Timer (MAX5023 only)
A watchdog timer asserts RESET if the watchdog input
(WDI) is not toggled for 1.6s (watchdog timeout period,
tWD). RESET remains low for 200ms (reset timeout peri-
od, tRP). If the watchdog is not updated for lengthy
periods of time, the reset output appears as a pulse
train, asserted for 200ms, deasserted for 1.6s, until WDI
is toggled again. Once RESET asserts, it stays low for
the entire reset timeout period ignoring any WDI transi-
tions during the reset timeout period.
Figure 2 shows the Watchdog Operation Timing
Diagram. To prevent the watchdog from asserting
RESET, toggle WDI with a valid rising or falling edge
prior to tWD (min) = 1.12s. The watchdog counter clears
when WDI toggles prior to tWD or when RESET asserts.
The watchdog resumes counting after RESET deasserts.
Enable and Hold Inputs
The MAX5023/MAX5024 support two logic inputs, EN
(active high) and HOLD (active low), making these
devices “automotive friendly.” For example, the ignition
drives EN high, the regulator turns on and remains on
even if EN goes low, as long as HOLD is forced low
and stays low after initial regulator power-up. This fea-
ture makes it possible to implement a self-holding
circuit without external components. Release HOLD (an
internal current source connects HOLD to OUT) to turn
the regulator off.
Force EN low and HOLD high to place the MAX5023/
MAX5024 into shutdown mode. Shutdown mode draws
less than 16µA of supply current. Table 1 shows the state
of the regulator output with respect to the voltage level at
65V, Low-Quiescent-Current, High-Voltage Linear
Regulators with µP Reset and Watchdog Timer
8_______________________________________________________________________________________
VOUT WHEN WATCHDOG IS HELD
HIGH AND EN = HIGH
VOUT WHEN WATCHDOG IS HELD
LOW AND EN = HIGH
BATT
BATT
BATT
BATT
POR NORMAL OPERATION WDI HELD HIGH
POR NORMAL OPERATION WDI HELD LOW
EN
WDI
RESET
VOUT
OV
OV
OV
OV
OV
OV
VIN
EN
WDI
RESET
VOUT
VIN
Figure 2. Watchdog Operation Timing Diagram
EN and HOLD. Figure 3 shows the timing diagram for the
enable and hold functions. Connecting HOLD to OUT or
floating HOLD allows the EN input to act as a standard
ON/OFF switch for the regulator output.
Thermal Protection
When the junction temperature exceeds TJ= +150°C, an
internal thermal sensor signals the shutdown logic that
turns off the pass transistor and allows the IC to cool.
The thermal sensor turns the pass transistor on again
after the IC’s junction temperature cools by 20°C, result-
ing in a cycled output during continuous thermal-over-
load conditions. Thermal protection protects the
MAX5023/MAX5024 in the event of fault conditions. For
continuous operation, do not exceed the absolute maxi-
mum junction temperature rating of TJ= +150°C.
Applications Information
Output Voltage Selection (MAX5024 only)
The MAX5024 features Dual Mode™operation: it oper-
ates in either a preset voltage mode or an adjustable
mode. In preset voltage mode, internal trimmed feed-
back resistors set the MAX5024’s internal linear
regulator to +3.3V or +5V (see the Selector Guide).
MAX5023/MAX5024
65V, Low-Quiescent-Current, High-Voltage Linear
Regulators with µP Reset and Watchdog Timer
_______________________________________________________________________________________ 9
Dual Mode is a trademark of Maxim Integrated Products, Inc.
VRESET
VOUT
VHOLD
0.2V
200ms
VTH
>10µs>10µs
1)
2)
3)
4) 6)
7)
8)
9)
5)
VOUT (NOM)
VHOLD, HOLD
VHOLD, REL
VEN, OFF
VEN, ON
1) ENABLE ACTIVE
2) HOLD INACTIVE, PULLED UP BY VOUT
3) POWER-ON RESET
4) HOLD ACTIVE, CLAMPED TO GND BY EXTERNAL µP
5) ENABLE INACTIVE, CLAMPED BY INT, PULLDOWN RESISTOR
6) PULSE WIDTH SMALLER THAN 10µs
7) HOLD INACTIVE, RELEASED BY µP
8) REGULATOR OUTPUT SHUTDOWN
9) OUTPUT-LOW RESET
VEN
VIN
Figure 3. Enable and Hold Behavior