MAXIM MAX5024_ASA

19-2619; Rev 2; 5/05
65V, Low-Quiescent-Current, High-Voltage Linear
Regulators with µP Reset and Watchdog Timer
Features
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 withstand 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.
♦ Wide Operating Input Voltage Range
+6.5V to +65V
In addition to an enable input to turn on or off the regulator, 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 regulator 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 regulator’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.
♦ Operate Over -40°C to +125°C Temperature Range
Applications
Automotive
Fire/Smoke Alarms
Industrial
Telecom/Networking
♦ 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
♦ 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)
Ordering Information
PART
TEMP RANGE
MAX5023_ ASA
-40°C to +125°C
8 SO-EP*
PIN-PACKAGE
MAX5024_ ASA
-40°C to +125°C
8 SO-EP*
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.
Selector Guide and Typical Operating Circuit appear at end
of data sheet.
Home Security
Pin Configurations
TOP VIEW
8
OUT
IN
7
WDI
EN 2
3
6
N.C.
RESET 4
5
HOLD
IN 1
EN 2
1
8
OUT
7
SET
3
6
N.C.
RESET 4
5
HOLD
MAX5024
MAX5023
GND
SO-EP
GND
SO-EP
________________________________________________________________ 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
MAX5023/MAX5024
General Description
MAX5023/MAX5024
65V, Low-Quiescent-Current, High-Voltage Linear
Regulators with µP Reset and Watchdog Timer
ABSOLUTE MAXIMUM RATINGS
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 (VIN ≤ +14V)............................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
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
(VIN = +14V, IOUT = 1mA, CIN = 10µF, COUT = 15µF, VEN = +2.4V, HOLD = open, 10kΩ from RESET to OUT, TA = -40°C to +125°C,
unless otherwise noted. Typical specifications are at TA = +25°C.) (Note 1)
PARAMETER
Input Voltage Range
Reverse Input Current
Supply Current
Shutdown Supply Current
SYMBOL
CONDITIONS
MIN
VIN
VIN must be at least 1.5V greater than VOUT
6.5
IREVERSE
IQ
VIN = -60V
Measured at GND
IOUT = 0mA
IOUT = 150mA
TYP
MAX
UNITS
65
V
0.1
10
µA
58
140
2000
ISHDN
VEN ≤ +0.4V
IOUT
VOUT = +5V
150
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
ILOAD = 150mA, VOUT = +5V (Note 2)
0.9
1.5
Rising edge of VIN to VOUT, RL = 500Ω,
SET = GND
400
6
16
µA
µA
REGULATOR
Guaranteed Output Current
Output Voltage
VOUT
Dropout Voltage
∆VDO
IOUT = 5mA, adjustable version (MAX5024)
Startup Response Time
Line Regulation
∆VOUT/
∆VIN
Enable Voltage
VEN
Enable Input Current
IEN
HOLD Voltage
VIL
Regulator on, EN transition from high to low
HOLD Release Voltage
VIH
EN = low, regulator shuts off
HOLD Pullup Current
IHOLD
Internally connected to OUT
SET Reference Voltage
VSET
IOUT = 10mA
SET Input Leakage Current
ISET
2
+8V ≤ VIN ≤ +65V
+5V version
+3.3V version
EN = high, regulator on
mA
2.5
11
+1
-0.5
0.5
2.4
EN = low, regulator off
0.4
VEN = +2.4V
0.5
VEN = +14V
4
V
µs
-1
mV/V
V
µA
0.4
VOUT 0.4V
V
V
4
1.223
V
µA
1.248
1.273
V
0.5
100
nA
_______________________________________________________________________________________
65V, Low-Quiescent-Current, High-Voltage Linear
Regulators with µP Reset and Watchdog Timer
(VIN = +14V, IOUT = 1mA, CIN = 10µF, COUT = 15µF, VEN = +2.4V, HOLD = open, 10kΩ from RESET to OUT, TA = -40°C to +125°C,
unless otherwise noted. Typical specifications are at TA = +25°C.) (Note 1)
PARAMETER
SYMBOL
∆VOUT/
∆IOUT
Load Regulation
Power-Supply Rejection Ratio
Short-Circuit Current
Thermal-Shutdown
Temperature
Thermal-Shutdown Hysteresis
CONDITIONS
MIN
TYP
MAX
UNITS
IOUT = 1mA to 150mA
1
mV/mA
IOUT = 10mA, f = 100Hz, 500mVP-P,
VOUT = +5V
54
dB
300
mA
TJ(SHDN)
150
°C
∆TJ(SHDN)
20
°C
PSRR
ISC
VIN = +8V
175
RESET CIRCUIT
Reset Threshold
VTH
Reset Timeout Period
tRP
VOUT to Reset Delay
tRD
Open-Drain RESET Output
Voltage (Note 4)
Open-Drain RESET OutputLeakage Current
VOL
ILKG
MAX502_L, SET = GND
4.50
4.625
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
MAX5024M/S, SET = Divider
(Figure 1) (Note 3)
0.875 x
VOUT
140
VOUT falling
200
4.75
260
5
V
ms
µs
VOUT ≥ +1.0V, ISINK = 50µA,
RESET asserted
0.3
VOUT ≥ +2.85V, ISINK = 1.2mA,
RESET asserted
0.3
VOUT ≥ +4.25V, ISINK = 3.2mA,
RESET asserted
0.4
RESET not asserted, VRESET = +11V
1.0
µA
2.08
s
V
WATCHDOG FUNCTION
Watchdog Timeout Period
tWD
WDI Pulse Width
tWDI
WDI Input Voltage
WDI Input Current
1.12
(Note 5)
50
VIL
ns
0.4
2.4
VIH
IWDI
1.6
WDI = GND
-1
+1
V
µA
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.
_______________________________________________________________________________________
3
MAX5023/MAX5024
ELECTRICAL CHARACTERISTICS (continued)
Typical Operating Characteristics
(VIN = +14V, CIN = 10µF, COUT = 15µF, VEN = +2.4V, VOUT = +5V, SET = GND, TA = +25°C, unless otherwise specified.)
NO-LOAD GROUND CURRENT
vs. TEMPERATURE
5.0
4.5
90
4.0
2.5
60
40
1.5
1.0
20
0.5
10
IOUT = 0mA
VIN = +14V
50
30
0
ISHDN (µA)
IGND (µA)
VIN = +6.5V
14
11
8
5
0
0 5 10 15 20 25 30 35 40 45 50 55 60 65
-40 -25 -10 5 20 35 50 65 80 95 110 125
-40 -25 -10 5 20 35 50 65 80 95 110 125
VIN (V)
TEMPERATURE (°C)
TEMPERATURE (°C)
OUTPUT VOLTAGE
vs. TEMPERATURE
GROUND CURRENT
vs. TEMPERATURE
OUTPUT VOLTAGE
vs. LOAD CURRENT AND TEMPERATURE
5.15
2.00
1.75
5.10
1.50
5.00
4.95
1.00
0.50
4.80
0.25
IOUT = 1mA
4.75
5.2
1.25
4.85
5.3
ILOAD = 150mA
ILOAD = 100mA
ILOAD = 50mA
5.1
5.0
4.9
0.75
4.90
5.4
VOUT (V)
IGND (mA)
5.05
5.5
MAX5023 toc06
5.20
MAX5023 toc05
2.25
MAX5023 toc04
5.25
ILOAD = 100mA
4.8
ILOAD = 150mA
4.7
4.6
ILOAD = 50mA
0
4.5
-40 -25 -10 5 20 35 50 65 80 95 110 125
-40 -25 -10 5 20 35 50 65 80 95 110 125
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
DROPOUT VOLTAGE
vs. LOAD CURRENT
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
LOAD-TRANSIENT RESPONSE
1.35
1.20
MAX5023 toc09
0
MAX5023 toc07
1.50
MAX5023 toc08
VOUT (V)
3.0
2.0
-10
-20
VOUT
100mV/div
PSRR (dB)
1.05
0.90
0.75
0.60
-30
-40
-50
0.45
IOUT
100mA/div
-60
0.30
0.15
COUT = 15µF
IOUT = 10mA
-70
VOUT = 5V
-80
0
10
30
50
70
90
ILOAD (mA)
4
17
70
3.5
VOUT (V)
VIN = +65V
80
20
MAX5023 toc02
100
MAX5023 toc01
5.5
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
MAX5023 toc03
OUTPUT VOLTAGE
vs. INPUT VOLTAGE
DROPOUT VOLTAGE (V)
MAX5023/MAX5024
65V, Low-Quiescent-Current, High-Voltage Linear
Regulators with µP Reset and Watchdog Timer
110
130
150
0.1
1
10
100
1000
200µs/div
FREQUENCY (kHz)
_______________________________________________________________________________________
65V, Low-Quiescent-Current, High-Voltage Linear
Regulators with µP Reset and Watchdog Timer
INPUT VOLTAGE STEP RESPONSE
ENABLE STARTUP RESPONSE
(VIN = +14V)
STARTUP RESPONSE
MAX5023 toc10
MAX5023 toc11
5V
VOUT
1V/div
VEN = VIN
IOUT = 1mA
5V
MAX5023 toc12
VEN
1V/div
VOUT
1V/div
65V
VIN
20V/div
VEN = VIN
IOUT = 1mA
6.5V
VOUT
2V/div
0V
65V
VIN
50V/div
0V
IOUT = 0mA
200µs/div
200µs/div
ENABLE STARTUP RESPONSE (VIN = +14V)
100µs/div
ENABLE STARTUP RESPONSE (VIN = +65V)
ENABLE STARTUP RESPONSE (VIN = +65V)
MAX5023 toc13
MAX5023 toc15
MAX5023 toc14
VEN
1V/div
VEN
1V/div
VEN
1V/div
VOUT
2V/div
VOUT
2V/div
VOUT
2V/div
IOUT = 150mA
IOUT = 150mA
IOUT = 0mA
100µs/div
100µs/div
100µs/div
ENABLE AND HOLD TIMING
SHUTDOWN RESPONSE
MAX5023 toc17
MAX5023 toc16
VEN
1V/div
VEN
5V/div
VHOLD
5V/div
VOUT
2V/div
VOUT
5V/div
IOUT = 1mA
40ms/div
200ms/div
_______________________________________________________________________________________
5
MAX5023/MAX5024
Typical Operating Characteristics (continued)
(VIN = +14V, CIN = 10µF, COUT = 15µF, VEN = +2.4V, VOUT = +5V, SET = GND, TA = +25°C, unless otherwise specified.)
Typical Operating Characteristics (continued)
(VIN = +14V, CIN = 10µF, COUT = 15µF, VEN = +2.4V, VOUT = +5V, SET = GND, TA = +25°C, unless otherwise specified.)
GROUND-CURRENT DISTRIBUTION
(TA = +40°C)
GROUND-CURRENT DISTRIBUTION
(TA = +125°C)
25
NUMBER OF UNITS
25
20
15
10
MAX5023toc19
30
MAX5023toc18
30
NUMBER OF UNITS
MAX5023/MAX5024
65V, Low-Quiescent-Current, High-Voltage Linear
Regulators with µP Reset and Watchdog Timer
5
20
15
10
5
0
0
47 48 51 52 53 54 55 56 57 58 59 60 61 80
45 53 56 57 58 59 60 61 62 63 64 65 89
IGND (µA)
IGND (µA)
Pin Description
PIN
NAME
FUNCTION
MAX5023
MAX5024
1
1
IN
Regulator Input. Supply voltage ranges from +6.5V to +65V. Bypass with a 10µF capacitor to
GND.
2
2
EN
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.
3
3
GND
Ground. GND also functions as a heatsink. Solder to large pads or the circuit-board ground
plane to maximize thermal dissipation.
4
4
RESET
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.
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).
6
5
5
HOLD
6
6
N.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.
8
8
OUT
Regulator Output. Fixed (+3.3V or +5V) or adjustable (+2.5V to +11V). Bypass with a 15µF
capacitor (min).
—
7
SET
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.
_______________________________________________________________________________________
65V, Low-Quiescent-Current, High-Voltage Linear
Regulators with µP Reset and Watchdog Timer
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 regulator 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 output voltages of +3.3V and +5V. The MAX5024 also features 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.
Functional Diagram
IN
+6.5V to +65V
REVERSE BATTERY PROTECTION
OUT
4µA
HOLD
EN
CONTROL
LOGIC
BANDGAP
REFERENCE
AMP
+2.5V to +11V
OUT
THERMAL
SENSOR
MUX
R1
COMP
SET
CURRENT
SENSOR AND
REGULATOR
(MAX5024 ONLY)
R2
TO INTERNAL SHUTDOWN
CIRCUITRY
RESET
WDI*
*MAX5023 ONLY.
WATCHDOG
TIMER AND
LOGIC
200ms
TIMEOUT
PERIOD
GND
Figure 1. Functional Diagram
_______________________________________________________________________________________
7
MAX5023/MAX5024
Detailed Description
MAX5023/MAX5024
65V, Low-Quiescent-Current, High-Voltage Linear
Regulators with µP Reset and Watchdog Timer
BATT
VIN
BATT
EN
VOUT WHEN WATCHDOG IS HELD
HIGH AND EN = HIGH
WDI OV
RESET OV
VOUT OV
POR
NORMAL OPERATION
WDI HELD HIGH
NORMAL OPERATION
WDI HELD LOW
BATT
VIN
BATT
EN
VOUT WHEN WATCHDOG IS HELD
LOW AND EN = HIGH
WDI OV
RESET OV
VOUT OV
POR
Figure 2. Watchdog Operation Timing Diagram
Reset Output
The reset supervisor circuit is fully integrated in the
MAX5023/MAX5024 and uses the same reference voltage as the regulator. RESET asserts during powerup/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 period, 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 transitions during the reset timeout period.
8
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 feature 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
load conditions. Thermal protection protects the
MAX5023/MAX5024 in the event of fault conditions. For
continuous operation, do not exceed the absolute maximum junction temperature rating of TJ = +150°C.
Thermal Protection
Applications Information
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, resulting in a cycled output during continuous thermal-over-
Output Voltage Selection (MAX5024 only)
The MAX5024 features Dual Mode™ operation: it operates in either a preset voltage mode or an adjustable
mode. In preset voltage mode, internal trimmed feedback resistors set the MAX5024’s internal linear
regulator to +3.3V or +5V (see the Selector Guide).
VIN
VEN
VEN, ON
5)
1)
VEN, OFF
>10µs
>10µs
VHOLD
VHOLD, REL
2)
4)
VHOLD, HOLD
6)
7)
VOUT
VTH
VOUT (NOM)
8)
200ms
VRESET
3)
9)
0.2V
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
Figure 3. Enable and Hold Behavior
Dual Mode is a trademark of Maxim Integrated Products, Inc.
_______________________________________________________________________________________
9
MAX5023/MAX5024
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.
Table 1. Truth Table for Regulator Output
State
+6.5V TO +65V
ORDER
1
2
EN
Low
High
HOLD
X
X
OUT
Off
10µF
Initial state. EN has 5MΩ
internal resistor to ground.
HOLD has internal current
source to OUT.
On
Regulator output is active
when EN is pulled high.
3
High
Low
On
Hold is asserted forcing the
regulator output on even if
EN goes low.
4
X
Low
On
Self-holding state. Regulator
output stays on regardless of
the state of EN.
5
Low
High
Off
Regulator output is
shutdown by releasing
HOLD while EN remains low.
+2.5V TO +11V
OUT
IN
COMMENTS
15µF
MAX5024
HOLD
ON
OFF
R1
EN
SET
TO µP
R2
RESET
GND
VOUT = VSET (1 + R1 / R2)
VSET = 1.248V
R2 = 1kΩ TO 500kΩ
Figure 4. Setting the MAX5024 Adjustable Output Voltage
X = Don’t care.
Select preset voltage mode by connecting SET to
ground. In adjustable mode, select an output between
+2.5V and +11V using two external resistors connected
as a voltage-divider to SET (Figure 4). Set the output
voltage using the following equation:
VOUT = VSET (1 + R1 / R2)
where VSET = 1.248V and R2 ≅ 100kΩ.
Available Output Current Calculation
The MAX5023/MAX5024 high-voltage regulator provides up to 150mA of output current. The input voltage
extends to +65V. Package power dissipation limits the
amount of output current available for a given input/
output voltage and ambient temperature. Figure 5
depicts the maximum power dissipation curve for these
devices. The graph assumes that the exposed metal
pad of the MAX5023/MAX5024 package is soldered to
1in2 of PC board copper.
Use Figure 5 to determine the allowable package dissipation for a given ambient temperature. Alternately, use
the following formula to calculate the allowable package dissipation:
1.538W for TA ≤ +70°C

PD = 

1.538 - 0.01923 ( TA - 70°C) for + 70°C < TA ≤ +125°C
10
PD (W)
MAX5023/MAX5024
65V, Low-Quiescent-Current, High-Voltage Linear
Regulators with µP Reset and Watchdog Timer
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
1.538W
DERATE
19.23mW/°C
10 20 30 40 50 60 70 80 90 100 110 120 130 140 150
TA (°C)
Figure 5. Maximum Power Dissipation vs. Temperature
After determining the allowable package dissipation,
calculate the maximum output current using the following formula:
IOUT(MAX) ≅
PD
≤ 150mA
VIN - VOUT
The above equations do not include the negligible
power dissipation from self-heating due to the IC
ground current.
______________________________________________________________________________________
65V, Low-Quiescent-Current, High-Voltage Linear
Regulators with µP Reset and Watchdog Timer
MAX5023/MAX5024
Example 1:
TA = +95°C
PD = 1.538W - (0.01923W/ °C) (95°C - 70°C)
= 1.057W
Then determine the maximum output current:
IOUT(MAX) =
(1.057W) = 117.4mA
14
( V) - (5V)
0.16
VOUT = +5V
DEVICE EXPOSED
PAD SOLDERED TO
1IN2 COPPER ISLAND
0.14
0.12
IOUT(MAX) (A)
VIN = +14V
VOUT = +5V
Find the maximum allowable output current. First calculate package dissipation at the given temperature as
follows:
0.10
MAX5023 fig04
MAXIMUM OUTPUT CURRENT
vs. INPUT VOLTAGE
TA = +70°C
0.08
TA = +85°C
0.06
0.04
0.02
TA = +125°C
0
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70
VIN (V)
Figure 6. Maximum Output Current vs. Input Voltage
Example 2:
TA = +125°C
VIN = +14V
VOUT = +3.3V
Calculate package dissipation at the given temperature
as follows:
PD = 1.538W - (0.01923W/ °C) (125°C - 70°C)
= 480.4mW
And establish the maximum current:
IOUT(MAX) =
(480.4mW) = 44.89mA
(14 V) - (3.3V)
Example 3:
TA = +50°C
VIN = +14V
VOUT = +5V
Calculate package dissipation at the given temperature
as follows:
PD = 1.538W
And find the maximum output current:
IOUT(MAX) =
In Example 3, the maximum output current is calculated
as 170.9mA, however, the maximum output current
cannot exceed 150mA. Use Figure 6 to quickly determine allowable maximum output current for selected
ambient temperatures.
Capacitor Selection and Regulator
Stability
For stable operation over the full temperature range
and with load currents up to 150mA, use a 15µF (min)
output capacitor with an ESR < 0.5Ω. To reduce noise
and improve load-transient response, stability, and
power-supply rejection, use larger output capacitor values such as 22µF.
Some ceramic dielectrics exhibit large capacitance
and ESR variation with temperature. For dielectric
capacitors such as Z5U and Y5V, use 22µF or more to
ensure stability at temperatures below -10°C. With X7R
or X5R dielectrics, 15µF should be sufficient at all operating temperatures. For high-ESR tantalum capacitors
use 22µF or more to maintain stability. To improve
power-supply rejection and transient response use a
minimum 10µF capacitor between IN and GND.
(1.538W) = 170.9mA ⇒ I
OUT(MAX) = 150mA
(14 V) - (5V)
______________________________________________________________________________________
11
Selector Guide
RESET THRESHOLD
(VTH)
PRESET VOUT
PART
5V
3.3V
MAX5023L
✔
MAX5023M
✔
MAX5023T
—
MAX5023S
MAX5024L
VOUT RESET
TOLERANCE
WATCHDOG
TIMER
ADJUSTABLE
REGULATOR
OUTPUT
—
VOUT 7.5%
VOUT 12.5%
—
✔
—
✔
—
—
✔
✔
—
—
✔
—
✔
—
—
✔
—
✔
✔
—
—
—
✔
—
—
✔
—
—
—
✔
—
✔
—
✔
—
✔
—
—
✔
—
—
✔
—
✔
—
✔
4.63V
4.38V
3.05V
2.89V
—
✔
—
—
—
—
✔
—
✔
—
—
✔
—
✔
—
—
✔
—
✔
—
MAX5024M
✔
—
—
✔
MAX5024T
—
✔
—
MAX5024S
—
✔
—
Bold Items indicate standard versions. Samples are generally available on standard versions only. Contact factory for availability of nonstandard versions. Set MAX5024’s adjustable output voltage by connecting a resistive-divider from OUT to SET (see the Output Voltage
Selection section).
Typical Operating Circuit
+6.5V TO +65V
VCC
OUT
IN
10µF
15µF
µP
MAX5023
10kΩ
RESET
ON
OFF
Chip Information
TRANSISTOR COUNT: 1382
PROCESS: BiCMOS
IGNITION
SWITCH
MAX5023/MAX5024
65V, Low-Quiescent-Current, High-Voltage Linear
Regulators with µP Reset and Watchdog Timer
RESET
EN
WDI
I/O
I/O
HOLD
GND
12
______________________________________________________________________________________
65V, Low-Quiescent-Current, High-Voltage Linear
Regulators with µP Reset and Watchdog Timer
8L, SOIC EXP. PAD.EPS
PACKAGE OUTLINE
8L SOIC, .150" EXPOSED PAD
21-0111
B
1
1
Note: For exposed pad dimension, use S8E-14 package dimensions.
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
© 2005 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products, Inc.
MAX5023/MAX5024
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.)