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19-2619; Rev 2; 5/05
65V, Low-Quiescent-Current, High-Voltage Linear Regulators with P Reset and Watchdog Timer
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 60A 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 (P) 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 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 P 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 (-40C to +125C) and are available in a thermally enhanced, surface-mount 8-pin SO-EP package.
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 60A No-Load Supply Current -60V Reverse-Battery Protection Preset +3.3V or +5.0V Output Voltage Thermal and Short-Circuit Protection Operate Over -40C to +125C Temperature Range Integrated P 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
Ordering Information
PART MAX5023_ ASA MAX5024_ ASA TEMP RANGE -40C to +125C -40C to +125C PIN-PACKAGE 8 SO-EP* 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.
Applications
Automotive Industrial Home Security Fire/Smoke Alarms Telecom/Networking
Pin Configurations
TOP VIEW
IN 1 EN 2 8 7 OUT WDI N.C. HOLD IN 1 8 7 OUT SET N.C. HOLD
EN 2
MAX5023
GND 3 6 5 GND 3 RESET 4 RESET 4
MAX5024
6 5
SO-EP
SO-EP
________________________________________________________________ Maxim Integrated Products
1
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65V, Low-Quiescent-Current, High-Voltage Linear Regulators with P Reset and Watchdog Timer MAX5023/MAX5024
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 = +70C) 8-Pin SO-EP (derate 19.2mW/C above +70C) ........1538mW Thermal Resistance: (JA) .............................................................................52C/W (JC) ...............................................................................2C/W Operating Temperature Range .........................-40C to +125C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C
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 = 10F, COUT = 15F, VEN = +2.4V, HOLD = open, 10k from RESET to OUT, TA = -40C to +125C, unless otherwise noted. Typical specifications are at TA = +25C.) (Note 1)
PARAMETER Input Voltage Range Reverse Input Current Supply Current Shutdown Supply Current REGULATOR Guaranteed Output Current IOUT VOUT = +5V SET = GND, IOUT = 1mA to 150mA, 5V version Output Voltage VOUT SET = GND, IOUT = 1mA to 150mA, 3.3V version IOUT = 5mA, adjustable version (MAX5024) Dropout Voltage Startup Response Time Line Regulation Enable Voltage Enable Input Current HOLD Voltage HOLD Release Voltage HOLD Pullup Current SET Reference Voltage SET Input Leakage Current VOUT/ VIN VEN IEN VIL VIH IHOLD VSET ISET VDO ILOAD = 150mA, VOUT = +5V (Note 2) Rising edge of VIN to VOUT, RL = 500, SET = GND +8V VIN +65V +5V version +3.3V version -1 -0.5 2.4 0.4 0.5 4 0.4 VOUT 0.4V 4 1.223 1.248 0.5 1.273 100 150 4.8 3.168 2.5 0.9 400 +1 0.5 5 3.3 5.2 3.432 11 1.5 V s mV/V V A V V A V nA V mA SYMBOL VIN IREVERSE IQ ISHDN VIN = -60V Measured at GND VEN +0.4V IOUT = 0mA IOUT = 150mA CONDITIONS VIN must be at least 1.5V greater than VOUT MIN 6.5 0.1 58 2000 6 16 TYP MAX 65 10 140 UNITS V A A A
EN = high, regulator on EN = low, regulator off VEN = +2.4V VEN = +14V Regulator on, EN transition from high to low EN = low, regulator shuts off Internally connected to OUT IOUT = 10mA
2
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65V, Low-Quiescent-Current, High-Voltage Linear Regulators with P Reset and Watchdog Timer
ELECTRICAL CHARACTERISTICS (continued)
(VIN = +14V, IOUT = 1mA, CIN = 10F, COUT = 15F, VEN = +2.4V, HOLD = open, 10k from RESET to OUT, TA = -40C to +125C, unless otherwise noted. Typical specifications are at TA = +25C.) (Note 1)
PARAMETER Load Regulation Power-Supply Rejection Ratio Short-Circuit Current Thermal-Shutdown Temperature Thermal-Shutdown Hysteresis RESET CIRCUIT MAX502_L, SET = GND MAX502_M, SET = GND MAX502_T, SET = GND Reset Threshold VTH MAX502_S, SET = GND MAX5024L/T, SET = Divider (Figure 1) (Note 3) MAX5024M/S, SET = Divider (Figure 1) (Note 3) Reset Timeout Period VOUT to Reset Delay tRP tRD VOUT falling VOUT +1.0V, ISINK = 50A, RESET asserted Open-Drain RESET Output Voltage (Note 4) VOL VOUT +2.85V, ISINK = 1.2mA, RESET asserted VOUT +4.25V, ISINK = 3.2mA, RESET asserted Open-Drain RESET OutputLeakage Current WATCHDOG FUNCTION Watchdog Timeout Period WDI Pulse Width WDI Input Voltage WDI Input Current tWD tWDI VIL VIH IWDI WDI = GND 2.4 -1 +1 (Note 5) 1.12 50 0.4 1.6 2.08 s ns V A ILKG RESET not asserted, VRESET = +11V 140 4.50 4.25 2.970 2.805 4.625 4.375 3.052 2.887 0.925 x VOUT 0.875 x VOUT 200 5 0.3 0.3 0.4 1.0 A V 260 ms s 4.75 4.50 3.135 2.970 V SYMBOL VOUT/ IOUT PSRR ISC TJ(SHDN) TJ(SHDN) CONDITIONS IOUT = 1mA to 150mA IOUT = 10mA, f = 100Hz, 500mVP-P, VOUT = +5V VIN = +8V 175 MIN TYP 1 54 300 150 20 MAX UNITS mV/mA dB mA C C
MAX5023/MAX5024
Note 1: Limits at -40C 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.
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65V, Low-Quiescent-Current, High-Voltage Linear Regulators with P Reset and Watchdog Timer MAX5023/MAX5024
Typical Operating Characteristics
(VIN = +14V, CIN = 10F, COUT = 15F, VEN = +2.4V, VOUT = +5V, SET = GND, TA = +25C, unless otherwise specified.)
OUTPUT VOLTAGE vs. INPUT VOLTAGE
MAX5023 toc01
NO-LOAD GROUND CURRENT vs. TEMPERATURE
MAX5023 toc02
SHUTDOWN SUPPLY CURRENT vs. TEMPERATURE
MAX5023 toc03
5.5 5.0 4.5 4.0 3.0 2.5 2.0 1.5 1.0 0.5 0 IOUT = 0mA 3.5 VOUT (V)
100 90 80 70 IGND (A) 60 50 40 30 20 10 0 VIN = +6.5V VIN = +65V
20
17
ISHDN (A)
VIN = +14V
14
11
8
5 -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (C) -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (C)
0 5 10 15 20 25 30 35 40 45 50 55 60 65 VIN (V)
OUTPUT VOLTAGE vs. TEMPERATURE
MAX5023 toc04
GROUND CURRENT vs. TEMPERATURE
MAX5023 toc05
OUTPUT VOLTAGE vs. LOAD CURRENT AND TEMPERATURE
5.4 5.3 5.2 VOUT (V) 5.1 5.0 4.9 ILOAD = 100mA ILOAD = 150mA ILOAD = 50mA
MAX5023 toc06
5.25 5.20 5.15 5.10
2.25 2.00 1.75 1.50 IGND (mA) 1.25 1.00 0.75 0.50 0.25 ILOAD = 100mA ILOAD = 150mA
5.5
VOUT (V)
5.05 5.00 4.95 4.90 4.85 4.80 4.75 TEMPERATURE (C) IOUT = 1mA -40 -25 -10 5 20 35 50 65 80 95 110 125
4.8 4.7
ILOAD = 50mA -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (C)
4.6 4.5 -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (C)
0
DROPOUT VOLTAGE vs. LOAD CURRENT
1.35 1.20 DROPOUT VOLTAGE (V) 1.05 0.90 0.75 0.60 0.45 0.30 0.15 0 10 30 50 70 90 110 130 150 ILOAD (mA) VOUT = 5V -70 -80 0.1 PSRR (dB) -30 -40 -50 -60
MAX5023 toc07
POWER-SUPPLY REJECTION RATIO vs. FREQUENCY
-10 -20
MAX5023 toc08
LOAD-TRANSIENT RESPONSE
MAX5023 toc09
1.50
0
VOUT 100mV/div
IOUT 100mA/div COUT = 15F IOUT = 10mA 1 10 FREQUENCY (kHz) 100 1000 200s/div
4
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65V, Low-Quiescent-Current, High-Voltage Linear Regulators with P Reset and Watchdog Timer MAX5023/MAX5024
Typical Operating Characteristics (continued)
(VIN = +14V, CIN = 10F, COUT = 15F, VEN = +2.4V, VOUT = +5V, SET = GND, TA = +25C, unless otherwise specified.)
INPUT VOLTAGE STEP RESPONSE
MAX5023 toc10
STARTUP RESPONSE
MAX5023 toc11
ENABLE STARTUP RESPONSE (VIN = +14V)
VEN 1V/div
MAX5023 toc12
5V VOUT 1V/div
5V
VEN = VIN IOUT = 1mA
65V VIN 20V/div 6.5V 200s/div VEN = VIN IOUT = 1mA
VOUT 1V/div VOUT 2V/div
0V 65V VIN 50V/div 0V 200s/div
IOUT = 0mA 100s/div
ENABLE STARTUP RESPONSE (VIN = +14V)
MAX5023 toc13
ENABLE STARTUP RESPONSE (VIN = +65V)
MAX5023 toc14
ENABLE STARTUP RESPONSE (VIN = +65V)
MAX5023 toc15
VEN 1V/div
VEN 1V/div
VEN 1V/div
VOUT 2V/div
VOUT 2V/div IOUT = 150mA 100s/div 100s/div
VOUT 2V/div
IOUT = 0mA 100s/div
IOUT = 150mA
SHUTDOWN RESPONSE
MAX5023 toc16
ENABLE AND HOLD TIMING
MAX5023 toc17
VEN 1V/div
VEN 5V/div VHOLD 5V/div
VOUT 2V/div VOUT 5V/div IOUT = 1mA 40ms/div 200ms/div
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65V, Low-Quiescent-Current, High-Voltage Linear Regulators with P Reset and Watchdog Timer MAX5023/MAX5024
Typical Operating Characteristics (continued)
(VIN = +14V, CIN = 10F, COUT = 15F, VEN = +2.4V, VOUT = +5V, SET = GND, TA = +25C, unless otherwise specified.)
GROUND-CURRENT DISTRIBUTION (TA = +40C)
MAX5023toc18
GROUND-CURRENT DISTRIBUTION (TA = +125C)
MAX5023toc19
30 25 NUMBER OF UNITS 20 15 10 5 0 47 48 51 52 53 54 55 56 57 58 59 60 61 80 IGND (A)
30 25 NUMBER OF UNITS 20 15 10 5 0 45 53 56 57 58 59 60 61 62 63 64 65 89 IGND (A)
Pin Description
PIN MAX5023 1 MAX5024 1 NAME IN FUNCTION Regulator Input. Supply voltage ranges from +6.5V to +65V. Bypass with a 10F capacitor to GND. 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 5M resistor. Ground. GND also functions as a heatsink. Solder to large pads or the circuit-board ground plane to maximize thermal dissipation. 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 4A pullup current source (see Table 1, Truth Table). No Connection. Not internally connected. 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. Regulator Output. Fixed (+3.3V or +5V) or adjustable (+2.5V to +11V). Bypass with a 15F capacitor (min). 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). Exposed Pad. Connect pad to GND.
2
2
EN
3
3
GND
4
4
RESET
5
5
HOLD
6 7 8
6 -- 8
N.C. WDI OUT
-- EP
7 EP
SET PAD
6
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65V, Low-Quiescent-Current, High-Voltage Linear Regulators with P Reset and Watchdog Timer
Detailed Description
The MAX5023/MAX5024 high-voltage linear regulators include an integrated P 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 P supply tolerance. Other features include reverse-voltage protection to -60V, enable (EN) and hold (HOLD) regulator control inputs, 16A (max) shutdown current, short-circuit protection, and thermal shutdown.
MAX5023/MAX5024
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 OUT 4A HOLD EN CONTROL LOGIC BANDGAP REFERENCE AMP +2.5V to +11V OUT
REVERSE BATTERY PROTECTION
THERMAL SENSOR
MUX R1 COMP
CURRENT SENSOR AND REGULATOR TO INTERNAL SHUTDOWN CIRCUITRY
SET (MAX5024 ONLY) R2
RESET
WDI*
WATCHDOG TIMER AND LOGIC
200ms TIMEOUT PERIOD
*MAX5023 ONLY.
GND
Figure 1. Functional Diagram _______________________________________________________________________________________ 7
65V, Low-Quiescent-Current, High-Voltage Linear Regulators with P Reset and Watchdog Timer MAX5023/MAX5024
BATT VIN EN VOUT WHEN WATCHDOG IS HELD HIGH AND EN = HIGH WDI OV RESET OV VOUT OV BATT
POR
NORMAL OPERATION
WDI HELD HIGH
BATT VIN EN VOUT WHEN WATCHDOG IS HELD LOW AND EN = HIGH WDI OV RESET OV VOUT OV POR NORMAL OPERATION WDI HELD LOW BATT
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.
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 16A of supply current. Table 1 shows the state of the regulator output with respect to the voltage level at
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
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65V, Low-Quiescent-Current, High-Voltage Linear Regulators with P Reset and Watchdog Timer
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. 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 = +150C.
MAX5023/MAX5024
Thermal Protection
When the junction temperature exceeds TJ = +150C, 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 20C, resulting in a cycled output during continuous thermal-overVIN
Applications Information
Output Voltage Selection (MAX5024 only)
The MAX5024 features Dual ModeTM 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).
VEN
VEN, ON VEN, OFF
1)
5)
>10s VHOLD
>10s
VHOLD, REL 2) VHOLD, HOLD 4) 6) 7)
VOUT VTH 8)
VOUT (NOM)
VRESET
200ms
3) 0.2V
9)
1) ENABLE ACTIVE 2) HOLD INACTIVE, PULLED UP BY VOUT 3) POWER-ON RESET 4) HOLD ACTIVE, CLAMPED TO GND BY EXTERNAL P 5) ENABLE INACTIVE, CLAMPED BY INT, PULLDOWN RESISTOR
6) PULSE WIDTH SMALLER THAN 10s 7) HOLD INACTIVE, RELEASED BY P 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
65V, Low-Quiescent-Current, High-Voltage Linear Regulators with P Reset and Watchdog Timer MAX5023/MAX5024
Table 1. Truth Table for Regulator Output State
+6.5V TO +65V +2.5V TO +11V IN 10F MAX5024 HOLD ON OFF EN SET TO P RESET GND R2 R1 OUT 15F
ORDER
EN
HOLD
OUT
COMMENTS Initial state. EN has 5M internal resistor to ground. HOLD has internal current source to OUT. Regulator output is active when EN is pulled high. Hold is asserted forcing the regulator output on even if EN goes low. Self-holding state. Regulator output stays on regardless of the state of EN. Regulator output is shutdown by releasing HOLD while EN remains low.
1
Low
X
Off
2
High
X
On
3
High
Low
On
4
X
Low
On
VOUT = VSET (1 + R1 / R2) VSET = 1.248V R2 = 1k TO 500k
5
Low
High
Off
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 100k.
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
PD (W)
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 +70C PD = 1.538 - 0.01923 ( TA - 70C) for + 70C < TA +125C
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.
10
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65V, Low-Quiescent-Current, High-Voltage Linear Regulators with P Reset and Watchdog Timer MAX5023/MAX5024
Example 1: TA = +95C VIN = +14V VOUT = +5V Find the maximum allowable output current. First calculate package dissipation at the given temperature as follows: PD = 1.538W - (0.01923W/ C) (95C - 70C) = 1.057W Then determine the maximum output current: IOUT(MAX) = Example 2: TA = +125C VIN = +14V VOUT = +3.3V Calculate package dissipation at the given temperature as follows: PD = 1.538W - (0.01923W/ C) (125C - 70C) = 480.4mW And establish the maximum current: IOUT(MAX) = Example 3: TA = +50C VIN = +14V VOUT = +5V Calculate package dissipation at the given temperature as follows: PD = 1.538W And find the maximum output current:
IOUT(MAX) =
0.16 0.14 0.12 IOUT(MAX) (A) 0.10 0.08 0.06 0.04 0.02 TA = +125C 0 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 VIN (V) TA = +85C
MAXIMUM OUTPUT CURRENT vs. INPUT VOLTAGE
VOUT = +5V DEVICE EXPOSED PAD SOLDERED TO 1IN2 COPPER ISLAND TA = +70C
MAX5023 fig04
(1.057W) = 117.4mA 14 V) - (5V) (
Figure 6. Maximum Output Current vs. Input Voltage
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 15F (min) output capacitor with an ESR < 0.5. To reduce noise and improve load-transient response, stability, and power-supply rejection, use larger output capacitor values such as 22F. Some ceramic dielectrics exhibit large capacitance and ESR variation with temperature. For dielectric capacitors such as Z5U and Y5V, use 22F or more to ensure stability at temperatures below -10C. With X7R or X5R dielectrics, 15F should be sufficient at all operating temperatures. For high-ESR tantalum capacitors use 22F or more to maintain stability. To improve power-supply rejection and transient response use a minimum 10F capacitor between IN and GND.
(480.4mW) = 44.89mA (14 V) - (3.3V)
(1.538W) = 170.9mA I OUT(MAX) = 150mA (14 V) - (5V)
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11
65V, Low-Quiescent-Current, High-Voltage Linear Regulators with P Reset and Watchdog Timer MAX5023/MAX5024
Selector Guide
PRESET VOUT PART 5V MAX5023L MAX5023M MAX5023T MAX5023S MAX5024L MAX5024M MAX5024T MAX5024S -- -- -- -- 3.3V -- -- -- -- 4.63V -- -- -- -- -- -- RESET THRESHOLD (VTH) 4.38V -- -- -- -- -- -- 3.05V -- -- -- -- -- -- 2.89V -- -- -- -- -- -- VOUT RESET TOLERANCE VOUT 7.5% -- -- -- -- VOUT 12.5% -- -- -- -- WATCHDOG TIMER -- -- -- -- ADJUSTABLE REGULATOR OUTPUT -- -- -- --
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 IN 10F OUT 15F MAX5023 10k RESET EN WDI HOLD GND I/O I/O RESET P
Chip Information
TRANSISTOR COUNT: 1382 PROCESS: BiCMOS
VCC
OFF
12
IGNITION SWITCH
ON
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65V, Low-Quiescent-Current, High-Voltage Linear Regulators with P Reset and Watchdog Timer 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.)
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 (c) 2005 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.
8L, SOIC EXP. PAD.EPS

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