MAX5091
28V, 100mA, Low-Quiescent-Current LDO
with Reset and Power-Fail Input/Output
General Description
Features
●●
●●
●●
●●
The MAX5091 high-voltage linear regulator is designed to
operate from a +5V to +28V input voltage, and withstands
up to 40V transients. The device consumes only 45μA of
quiescent current at 100μA output current. The MAX5091
delivers up to 100mA of output current with low 50mV
maximum dropout voltage. The MAX5091 provides an
active-low open-drain microprocessor RESET output. The
reset timeout period is programmable and can be set with
an external capacitor. The MAX5091 includes an uncommitted comparator for input voltage monitoring/powerfail indication. The device is available with a fixed +5V
(MAX5091A) or +3.3V (MAX5091B) output. The MAX5091
is short-circuit protected and includes thermal shutdown.
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●●
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The MAX5091 operates over the -40°C to +125°C automotive temperature range and is available in 8-pin, thermally enhanced TDFN-EP and SO-EP packages.
Applications
●● Industrial
●● Home Security/Safety
●●
●● Telecom/Networking
+5V to +28V Wide Operating Input Voltage Range
Withstands 40V Input Voltage Transients
Guaranteed 100mA Output Current
45μA Typical Quiescent Current at 100μA Output
Current
Preset +5V (MAX5091A) or +3.3V (MAX5091B)
Output Voltage
Stable with Only 10μF Output Capacitance
RESET Output with Adjustable Timeout Period
Uncommitted Comparator for Voltage Monitoring/
Power-Fail Indication
Output Overload and Short-Circuit Protection
Thermal Shutdown
Available in 8-Pin TDFN (1.95W at TA = +70°C) and
8-Pin SO (1.5W at TA = +70°C)
Operates Over -40°C to +125°C Automotive
Temperature Range
Ordering Information
PART
TEMP RANGE
MAX5091AATA+T
-40°C to +125°C
MAX5091AASA+
PRESET VOUT (V)
PIN-PACKAGE
5
8 TDFN-EP*
-40°C to +125°C
5
8 SO-EP*
MAX5091BATA+T
-40°C to +125°C
3.3
8 TDFN-EP*
MAX5091BASA+
-40°C to +125°C
3.3
8 SO-EP*
TOP MARK
+APB
—
+APC
—
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
T = Tape and reel.
Typical Application Circuit
VIN
+5V TO +28V
RH
288kΩ
CIN
10µF
VS
MAX5091
ON
OFF
VOUT
+5V (MAX5091A)/
+3.3V (MAX5091B)
100mA
µC
RESET
RSO
10kΩ
CCT
0.1µF
CT
GND
SO
VOUT
SO
8
7
RES GND
6
5
MAX5091
RES
RL
100kΩ
TOP VIEW
COUT
10µF
RRES
10kΩ
EN
SI
Pin Configurations
POWERFAIL
EXPOSED PADDLE
+
1
2
3
4
VS
SI
EN
CT
TDFN
(3mm x 3mm)
Pin Configurations continued at end of data sheet.
19-0654; Rev 1; 5/14
MAX5091
28V, 100mA, Low-Quiescent-Current LDO
with Reset and Power-Fail Input/Output
Absolute Maximum Ratings
VS to GND..............................................................-0.3V to +28V
VS to GND (t ≤ 1s)..................................................-0.3V to +40V
VOUT to GND..........................................................-0.3V to +20V
VS to OUT...............................................................-0.3V to +28V
RES, SO to GND.....................................................-0.3V to +20V
RES, SO Output Sink Current................................................5mA
VOUT Short Circuit (VS ≤ 16V)…………......................Continuous
EN, SI to GND.........................................................-0.3V to +12V
CT to GND.............................-0.3V to the lower of VOUT or +12V
Continuous Power Dissipation (TA = +70°C)
SO-EP (derate 19.2mW/°C above +70°C).......1538mW*
Thermal Resistance (θJA)............................................52°C/W
Thermal Resistance (θJC)..............................................6°C/W
TDFN-EP (derate 24.4mW/°C above +70°C)...1951mW**
Thermal Resistance (θJA)............................................41°C/W
Thermal Resistance (θJC)...........................................8.3°C/W
Operating Junction Temperature Range..............-40°C to +125°C
Maximum Junction Temperature.......................................+150°C
Storage Temperature Range...............................-60°C to +150°C
Lead Temperature (soldering, 10s)...................................+300°C
*As per JEDEC51 Standard (single-layer board).
**As per JEDEC51 Standard (multilayer board).
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 (MAX5091A)
(VS = +14V, VOUT = 5V, EN unconnected, TA = TJ = -40°C to +125°C, CIN = 10μF, COUT = 10μF, unless otherwise noted. Typical
specifications are at TA = +25°C.) (Note 1)
PARAMETER
Output Voltage
Dropout Voltage
SYMBOL
VOUT
VDP
CONDITIONS
MIN
TYP
MAX
TA = +25°C, IOUT = 1mA
4.95
5
5.05
5.6V ≤ VS ≤ 28V, IOUT = 1mA to 50mA
(Note 2)
4.90
5
5.10
5.6V ≤ VS ≤ 40V, t ≤ 1s, IOUT = 1mA to
30mA (Note 2)
4.9
5
5.1
VS = +8V, IOUT = 1mA to 100mA
4.9
5
5.1
IOUT = 10mA
0.1
0.25
IOUT = 50mA
0.2
0.4
IOUT = 100mA
0.3
0.5
VS = +4.75V
VS to VOUT Difference in
Undervoltage
VIO
VS = +4V, IOUT = 35mA
Line Regulation
VOL
+5.5V ≤ VS ≤ +28V, IOUT = 1mA
Load Regulation
VOLO
Current Limit
Quiescent Current
Shutdown Supply Current
Thermal-Shutdown Temperature
Thermal-Shutdown Hysteresis
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ISHDN
TJ(SHDN)
ΔTJ(SHDN)
V
0.6
1mA ≤ IOUT ≤ 100mA
V
0.4
V
5
mV
17
50
mV
260
400
mA
IOUT = 100µA
46
100
IOUT = 300µA
45
100
IOUT = 100mA
4.5
10
mA
17
30
µA
ILIM
IQ
UNITS
160
VEN ≤ +0.4V
Temperature rising
µA
+165
°C
20
°C
Maxim Integrated │ 2
MAX5091
28V, 100mA, Low-Quiescent-Current LDO
with Reset and Power-Fail Input/Output
Electrical Characteristics (MAX5091A) (continued)
(VS = +14V, VOUT = 5V, EN unconnected, TA = TJ = -40°C to +125°C, CIN = 10μF, COUT = 10μF, unless otherwise noted. Typical
specifications are at TA = +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
85
90
94.5
%VOUT
30
65
100
mV
55
110
180
ms
RESET
Reset Threshold Voltage
Reset Threshold Hysteresis
VRT
VOUT falling
VRTH
Reset Pulse Delay
tRD
CCT = 100nF, tR ≥ 100µs
RES Output Low Voltage
VRL
VS ≥ +1.5V, RRES = 10kΩ to VOUT
0.4
V
RES Output High Leakage
Current
IRH
VRES = 5V
1.0
µA
VCTTH
VCT rising
2.4
V
Delay Comparator Threshold
1.9
Delay Comparator Threshold
Hysteresis
2.1
100
mV
SENSE
Sense Threshold
VST
VSI falling
Sense Threshold Hysteresis
1.10
1.16
1.24
V
50
100
150
mV
0.4
V
1
µA
+1
µA
Sense Output Low Voltage
VSL
VSI ≤ 1.10V, VS ≥ 4V, RSO = 10kΩ to VOUT
Sense Output
Leakage Current
ISH
VSO = 5V, VSI ≥ 1.5V
Sense Input Current
ISI
VSI = 3.3V
-1
EN = high, regulator on
2.4
ENABLE
Enable Voltage
VEN
Enable Internal Pullup Current
IEN
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EN = low, regulator off
EN is internally pulled up to 3.6V (max)
0.4
3
V
µA
Maxim Integrated │ 3
MAX5091
28V, 100mA, Low-Quiescent-Current LDO
with Reset and Power-Fail Input/Output
Electrical Characteristics (MAX5091B)
(VS = +14V, VOUT = 3.3V, EN unconnected, TA = TJ = -40°C to +125°C, CIN = 10μF, COUT = 10μF, unless otherwise noted. Typical
specifications are at TA = +25°C.) (Note 1)
PARAMETER
Output Voltage
SYMBOL
VOUT
MIN
TYP
MAX
TA = +25°C, IOUT = 1mA
CONDITIONS
3.267
3.3
3.333
5V ≤ VS ≤ 28V, IOUT = 1mA to 50mA (Note 2)
3.234
3.3
3.366
5V ≤ VS ≤ 40V, t ≤ 1s, IOUT = 1mA to 30mA
(Note 2)
3.234
3.3
3.366
VS = +8V, IOUT = 1mA to 100mA
3.234
3.3
3.366
UNITS
V
VS to VOUT Difference in
Undervoltage
VIO
VS = 3.5V, IOUT = 35mA
0.2
0.4
V
Line Regulation
VOL
5V ≤ VS ≤ 28V, IOUT = 1mA
0.6
5
mV
Load Regulation
VOLO
Current Limit
Quiescent Current
Shutdown Supply Current
Thermal-Shutdown Temperature
Thermal-Shutdown Hysteresis
1mA ≤ IOUT ≤ 100mA
11
40
mV
260
400
mA
IOUT = 100µA
45
100
IOUT = 300µA
45
100
IOUT = 100mA
4.4
10
mA
17
30
µA
ILIM
IQ
ISHDN
TJ(SHDN)
160
VEN ≤ 0.4V
Temperature rising
ΔTJ(SHDN)
µA
+165
°C
20
°C
RESET CIRCUIT
Reset Threshold Voltage
Reset Threshold Hysteresis
VRT
VOUT falling
VRTH
Reset Pulse Delay
tRD
CCT = 100nF, tR ≥ 100µs
RES Output Low Voltage
VRL
VS ≥ 1.5V, RRES = 4kΩ to VOUT
IRH
VRES = 3.3V
RES Output High Leakage Current
Delay Comparator Threshold
Delay Comparator Threshold
Hysteresis
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VCTTH
VCT rising
85
90
94.5
%VOUT
20
45
80
mV
55
105
180
ms
0.4
V
1.0
µA
2.4
V
1.9
2.1
100
mV
Maxim Integrated │ 4
MAX5091
28V, 100mA, Low-Quiescent-Current LDO
with Reset and Power-Fail Input/Output
Electrical Characteristics (MAX5091B) (continued)
(VS = +14V, VOUT = 3.3V, EN unconnected, TA = TJ = -40°C to +125°C, CIN = 10μF, COUT = 10μF, unless otherwise noted. Typical
specifications are at TA = +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
1.09
1.15
1.23
V
50
100
150
mV
0.4
V
1
µA
+1
µA
SENSE
Sense Threshold
VST
VSI falling
Sense Threshold Hysteresis
Sense Output-Low Voltage
VSL
VSI ≤ 1.09V, VS ≥ 4V, RSO = 10kΩ to VOUT
Sense Output Leakage Current
ISH
VSO = 3.3V, VSI ≥ 1.5V
Sense Input Current
ISI
VSI = 3.3V
-1
EN = high, regulator on
2.4
ENABLE
Enable Voltage
VEN
Enable Internal Pullup Current
IEN
EN = low, regulator off
V
0.4
EN is internally pulled up to 3.6V (max)
3
µA
Note 1: Limits at TA = -40°C are guaranteed by design and not production tested.
Note 2: Maximum output current is limited by the power dissipation capability of the package.
Typical Operating Characteristics
(Typical Application Circuit, VS = +14V, CIN = 10μF, COUT = 10μF, VSI = 0V, VEN = +2.4V, VOUT = +5V, TA = +25°C, unless
otherwise noted.)
MAX5091A
5
OUTPUT VOLTAGE vs. OUTPUT CURRENT
OUTPUT VOLTAGE vs. INPUT VOLTAGE
VOUT AT NO LOAD, 100A,
1mA, 10mA, 100mA
MAX5091B
MAX5091A
5.04
5.02
3
VS = 14V
MAX5091 toc03
VOUT AT NO LOAD, 100A,
1mA, 10mA, 100mA
4
MAX5091 toc02
OUTPUT VOLTAGE vs. INPUT VOLTAGE
MAX5091 toc01
6
4
3
VOUT (V)
VOUT (V)
VOUT (V)
5.00
2
4.98
4.96
VS = 6V
4.94
1
4.92
2
0
5
10
VS (V)
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15
0
0
1
2
3
VS (V)
4
5
6
4.90
0.01
0.1
1
10
100
IOUT (mA)
Maxim Integrated │ 5
MAX5091
28V, 100mA, Low-Quiescent-Current LDO
with Reset and Power-Fail Input/Output
Typical Operating Characteristics (continued)
(Typical Application Circuit, VS = +14V, CIN = 10μF, COUT = 10μF, VSI = 0V, VEN = +2.4V, VOUT = +5V, TA = +25°C, unless
otherwise noted.)
OUTPUT VOLTAGE
vs. TEMPERATURE
IOUT = 1mA
4.975
IOUT = 10mA
4.950
IOUT = 100mA
-15
10
35
60
85
110
1
135
EN = OPEN
IOUT = NO LOAD
2
6
10
1
14 18 22 26 30 34 38
EN = OPEN
IOUT = 100A
2
6
10
14 18 22 26 30 34 38
RESET OUTPUT LOW
vs. TEMPERATURE
RRES = 4kΩ
40
MAX5091 toc08
10
VS = 14V
TA = +25°C
MAX5091 toc09
VS (V)
SHUTDOWN SUPPLY CURRENT
vs. INPUT VOLTAGE
VS = 14V
TA = +25°C
EN = 0V
30
IQ (mA)
ISHDN (µA)
1
0.10
RRES = 10kΩ
20
0.1
10
0.05
0.01
-40 -25 -10 5 20 35 50 65 80 95 110 125
10
0
100
0
10
20
30
17
16
15
-5
-30
65
TEMPERATURE (°C)
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100
135
325
300
275
250
225
200
175
150
125
100
75
50
25
0
MAX5091A
VS = 4.75V
0.1
1
10
IOUT (mA)
100
300
275
250
225
200
175
150
125
100
75
50
25
0
MAX5091B
VS = 3.3V
0.1
40
MAX5091 toc12
DROPOUT VOLTAGE
vs. LOAD CURRENT
DROPOUT VOLTAGE (mV)
DROPOUT VOLTAGE
vs. LOAD CURRENT
MAX5091 toc11
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
DROPOUT VOLTAGE (mV)
VS (V)
18
-40
1
IOUT (mA)
VS = 14V
EN = 0V
19
0.1
TEMPERATURE (°C)
MAX5091 toc10
20
ISHDN (µA)
TA = -40°C
10
QUIESCENT CURRENT
vs. OUTPUT CURRENT
0.15
14
TA = +25°C, +85°C
VS (V)
0.20
0
TA = +125°C
100
TEMPERATURE (°C)
MAX5091 toc07
-40
0.25
RESET OUTPUT LOW (V)
TA = +125°C
TA = -40°C
10
4.925
4.900
TA = +25°C, +85°C
100
IQ (µA)
VOUT (V)
5.000
MAX5091 toc06
IOUT = 100A
1000
IQ (µA)
5.025
1000
MAX5091 toc05
MAX5091A
MAX5091 toc04
5.050
QUIESCENT CURRENT
vs. INPUT VOLTAGE
QUIESCENT CURRENT
vs. INPUT VOLTAGE
1
10
100
IOUT (mA)
Maxim Integrated │ 6
MAX5091
28V, 100mA, Low-Quiescent-Current LDO
with Reset and Power-Fail Input/Output
Typical Operating Characteristics (continued)
(Typical Application Circuit, VS = +14V, CIN = 10μF, COUT = 10μF, VSI = 0V, VEN = +2.4V, VOUT = +5V, TA = +25°C, unless
otherwise noted.)
IOUT = 100mA
200
150
100
50
-40
-5
65
100
4.44
30
65
100
0
135
4.3
4.4
MAX5091 toc15
4.5
4.7
4.6
SENSE THRESHOLD
vs. TEMPERATURE
SENSE OUTPUT
vs. SENSE INPUT
POWER-SUPPLY REJECTION RATIO
vs. SUPPLY CURRENT
1.20
1.15
5
4
30
65
100
3
VSI FALLING
2
0
135
0
VIN = 14V
IOUT = 10mA
500mVP-P
-10
-20
VSI RISING
-30
-40
-50
-60
1
SI INPUT FALLING
-5
-5
VOUT (V)
1.25
-40
1
VOUT FALLING
-40
VOUT RISING
TEMPERATURE (°C)
1.30
1.05
VOUT FALLING
TEMPERATURE (°C)
SI INPUT RISING
1.10
3
2
4.46
SENSE OUTPUT (V)
SENSE THRESHOLD (V)
4.48
4.40
135
1.40
1.35
VOUT RISING
4.50
4.42
1.45
1.00
4.52
MAX5091 toc16
1.50
30
4
4.54
PSRR (dB)
0
IOUT = 10mA
4.56
MAX5091A
RRES = 10kΩ TO OUT
5
-70
1.0
1.1
1.2
1.3
1.4
-80
0.01
LOAD-TRANSIENT RESPONSE
10
100
MAX5091 toc20
VOUT
5V AC-COUPLED
200mV/div
IOUT = 1mA
VOUT
5V AC-COUPLED
100mV/div
40V
50mA
VS
10V/div
IOUT
20mA/div
14V
100µA
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1
FREQUENCY (kHz)
LINE-TRANSIENT RESPONSE
MAX5091 toc19
200µs/div
0.1
SENSE INPUT (V)
TEMPERATURE (°C)
CIN = 10µF
COUT = 10µF/10mΩ ESR
ISTEP = 100µA TO 50mA
MAX5091 toc18
250
MAX5091A
4.58
VRES (V)
300
4.60
RESET VOLTAGE
vs. OUTPUT VOLTAGE
MAX5091 toc17
DROPOUT VOLTAGE (mV)
350
RESET THRESHOLD
vs. TEMPERATURE
MAX5091 toc14
MAX5091A
VS = 4.75V
RESET THRESHOLD VOLTAGE (V)
400
MAX5091 toc13
DROPOUT VOLTAGE
vs. TEMPERATURE
200µs/div
Maxim Integrated │ 7
MAX5091
28V, 100mA, Low-Quiescent-Current LDO
with Reset and Power-Fail Input/Output
Typical Operating Characteristics (continued)
(Typical Application Circuit, VS = +14V, CIN = 10μF, COUT = 10μF, VSI = 0V, VEN = +2.4V, VOUT = +5V, TA = +25°C, unless
otherwise noted.)
VOUT STARTUP RESPONSE
ENABLE RESPONSE
MAX5091 toc21
IOUT = 10mA
IOUT = 100mA
VOUT
2V/div
VOUT
5V/div
0V
VS
5V/div
0V
EN
2V/div
EN
5V/div
0V
10ms/div
MAX5091 toc23
IOUT = 100mA
VOUT
2V/div
0V
0V
SHUTDOWN RESPONSE
MAX5091 toc22
200µs/div
0V
200µs/div
Pin Description
PIN
NAME
FUNCTION
1
VS
Regulator Input. Operating supply range is from +5V to +28V and withstands 40V transients. Bypass
VS to GND with a 10µF capacitor.
2
SI
Voltage Sense/Power-Fail Comparator Input. SI is the noninverting input of an uncommitted comparator. SO
asserts low if VSI drops below the reference level, VST.
3
EN
Enable Input. Leave unconnected (or pull EN high) to turn on the regulator. Pull EN low to place the device in
shutdown mode. EN is internally pulled up to 3.6V.
4
CT
Reset Timeout Delay Capacitor Connection. Connect a capacitor from CT to GND to program the reset timeout
period/reset pulse delay. During regulation, CT is pulled up to VOUT. CT is pulled low during reset, when EN is
low, or when in thermal shutdown.
5
GND
Ground. Bypass the input and output capacitors to the GND plane. Solder to large pads or the circuit-board
ground plane to maximize thermal dissipation.
6
RES
Active-Low Reset Output. Pull up externally to VOUT. Open-drain RES goes low when VOUT is below the reset
threshold. Once output voltage is in regulation, RES goes high after the programmed reset timeout period is
over. RES is low when EN is low or in thermal shutdown.
7
SO
8
VOUT
EP
EP
Voltage Sense/Power-Fail Comparator Output. Pull up externally to VOUT. Open-drain SO asserts
low when VSI drops below the reference level, VST. SO also asserts low when EN is low or in thermal
shutdown.
Regulator Output. Fixed at +5V (MAX5091A) or +3.3V (MAX5091B). Bypass with a 10µF ceramic capacitor to
GND.
Exposed Paddle. EP is internally connected to GND. Connect EP to GND to provide a low thermal-resistance
path from the IC junction to the PC board. Do not use as the only electrical connection to GND.
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Maxim Integrated │ 8
MAX5091
28V, 100mA, Low-Quiescent-Current LDO
with Reset and Power-Fail Input/Output
LDO
PASS
ELEMENT
VS
VINT
3µA
MAX
VOUT
MAX5091
VREF
GND
ENABLE
ALWAYS-ON
EN
VOUT
ICT
2µA
PREREGULATOR
ALWAYS-ON
VINT
3.6V (MAX)
N
DELAY
COMPARATOR
RES
N
2.1V
0.9 x VREF
SCLIM
FAULT
DETECTION
(TEMP AND SC)
CT
VREF
1.25V
SD
VREF
SO
SI
N
VREF
Figure 1. Functional Diagram
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Maxim Integrated │ 9
MAX5091
28V, 100mA, Low-Quiescent-Current LDO
with Reset and Power-Fail Input/Output
Detailed Description
SI/SO Comparator
Regulator
The MAX5091 high-voltage, LDO regulator operates
from +5V to +28V input voltage. The device withstands up to 40V transients, providing protection against
temporary overvoltage conditions like load dump. The
MAX5091 incorporates internal feedback resistors for
factory-preset voltages of either +5V (MAX5091A) or
+3.3V (MAX5091B). The regulator is capable of driving
up to 100mA of load current and features a typical current
limit of 260mA. The regulator uses a pnp pass element
and provides low 0.5V dropout while delivering 100mA
load current. The output of the regulator follows closely to
the input during turn-on. See the Output Voltage vs. Input
Voltage graph in the Typical Operating Characteristics.
This makes the usable input voltage range for 3.3V
and 5V output down to 3.7V and 5.5V, respectively. The
MAX5091 is designed to operate with very low quiescent
current during always-on operation when not in dropout.
The regulator is stable with a wide variety of capacitors
including low-ESR ceramic 10μF (0603 case size). The
load-transient response curves depict the stability of the
LDO when using different capacitance and ESR ranges.
See the Capacitor Selection and Regulator Stability section in the Applications Information.
Reset Output (RES)
The MAX5091 integrates a power-on-reset circuit. RES
is an open-drain output that requires a pullup resistor to
VOUT. The open-drain MOSFET can sink up to 825μA
current while keeping the RES voltage below 0.4V. The
internal reset circuit monitors the regulator output voltage
and RES asserts an active-low output when the regulator output falls below a reset threshold of typically 0.9 x
VOUT. The RES output remains low when VOUT is below
the reset threshold, and remains low for the duration of
the reset timeout period (tRD). The reset timeout period is
programmable and can be set with an external capacitor
connected from CT to ground. The duration of the delay
as a function of CT is:
(
C CT × VCCTH
=
t RD
+ 35 × 10 −6
I CT
)
where VCCTH = 2.1V and ICT = 2 x 10-6 A.
The default reset timeout period is 35μs when no capacitor is connected from CT to ground.
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The MAX5091 includes an uncommitted comparator for
monitoring the input voltage or for detecting power-fail conditions. The input SI is the noninverting input of the comparator. The open-drain output SO asserts low when voltage
at the input SI drops below the threshold voltage, VST (see
Figure 1). The sense comparator typically has a hysteresis
of 100mV. Use the following equation to calculate the resistor-divider for programming the trip voltage (VTRIP) during
power-fail. See the Typical Application Circuit.
V TRIP
=
(VST × R H) + V
RL
ST
where VST = 1.16V (typ). Choose RL between 100kΩ to
300kΩ.
Enable Input
The enable (EN) is a TTL-compatible logic input. Logic
low at EN turns off the regulator and reduces the current
consumption to 17μA (typ). It is internally pulled up to a
logic-high voltage (3.6V max) by an internal resistor. Thus,
the MAX5091 is enabled by default when VS is applied
and EN is left unconnected. The regulator, reset supervisor circuit, and the sense comparator can be manually
shut down by pulling EN low. For shutdown operation, the
pulldown network must be capable of sinking 3μA max,
since the internal pullup resistor sets the maximum pullup
current at 3μA. The external pulldown device should not
leak more than 1μA current when it is in the off-state.
Current Limit
The MAX5091 features a current limiter that monitors the
output current and controls the pass transistor’s gate voltage,
limiting the output current to typically 260mA. The output can
be continuously shorted to ground without damaging the
device at VS ≤ 16V. Note that the output short-circuit current
may increase the power dissipation significantly and raise the
junction temperature to its thermal-shutdown threshold. In
such a case, the MAX5091 is temporarily turned off.
Thermal Shutdown
When the junction temperature exceeds TJ = +165°C (typ),
an internal thermal sensor signals the shutdown logic to
turn off the pass transistor and allow the IC to cool. The
thermal sensor turns the pass transistor on again after the
IC’s junction temperature cools by +20°C (typ), resulting in
a cycled output during continuous thermal-overload conditions. Thermal shutdown protects the MAX5091 in the event
of fault conditions. For continuous operation, do not exceed
the absolute maximum junction temperature of TJ = +150°C.
Maxim Integrated │ 10
MAX5091
28V, 100mA, Low-Quiescent-Current LDO
with Reset and Power-Fail Input/Output
Applications Information
Available Output Current Calculation
The MAX5091 high-voltage regulator provides up to
100mA of output current. The input voltage extends to
+28V. Package power dissipation limits the amount of
output current available for a given input/output voltage
and ambient temperature. Figure 2 depicts the maximum
power dissipation curve for the 8-pin SO-EP package.
The graph assumes that the exposed metal back of the
MAX5091 package is soldered to copper on a single layer
PCB according to the JEDEC51 standard.
Use Figure 2 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
(T
−
70
°
C)
For
+
70
°
C
<
T
≤
+
125
°
C
A
A
After determining the allowable package dissipation,
calculate the maximum output current using the following
formula:
I OUT(MAX) ≅
PD
VS − VOUT
The above equations do not include the power dissipation
from self-heating due to the IC ground current.
The junction-to-ambient thermal impedance depends
on the area of the copper plane, its thickness, and the
number of copper layers on PCB. For the higher power
dissipation requirement, use multiple-layered PCBs with
2oz copper and a large copper area.
Capacitor Selection and Regulator Stability
For stable operation over the full temperature range
and with load currents up to 100mA, use a 10μF output
capacitor with a low ESR. Table 1 shows a list of recommended output capacitor ESR for various load conditions.
2.0
8-PIN SO-EP
1.8
1.538W
1.6
PD (W)
1.4
MAX5091 fig02
Table 1. Recommended Output Capacitor
ESR
DERATE
19.23mW/°C
1.2
1.0
RECOMMENDED COUT ESR
IOUT
VOUT = 3.3V
VOUT = 5.0V
IOUT ≤ 10mA
CESR < 0.66Ω
CESR < 1Ω
IOUT ≤ 50mA
CESR < 0.132Ω
CESR < 0.2Ω
IOUT ≤ 100mA
CESR < 66mΩ
CESR < 0.1Ω
0.8
0.6
0.4
0.2
0
10
20
30
50 70
90 110 130 150
40
60 80 100 120 140
TEMPERATURE (°C)
Figure 2. 8-Pin SO-EP Maximum Power Dissipation vs.
Temperature
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Maxim Integrated │ 11
MAX5091
28V, 100mA, Low-Quiescent-Current LDO
with Reset and Power-Fail Input/Output
Pin Configurations (continued)
Chip Information
PROCESS: BiCMOS
TOP VIEW
VS 1
+
SI 2
EN
MAX5091
3
CT 4
EXPOSED PADDLE
SO-EP
www.maximintegrated.com
8
VOUT
7
SO
6
RES
5
GND
Package Information
For the latest package outline information and land patterns
(footprints), go to www.maximintegrated.com/packages. Note
that a “+”, “#”, or “-” in the package code indicates RoHS status
only. Package drawings may show a different suffix character,
but the drawing pertains to the package regardless of RoHS
status.
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE
NO.
LAND
PATTERN NO.
8 TDFN-EP
T833+2
21-0137
90-0059
8 SO-EP
S8E+14
21-0111
90-0151
Maxim Integrated │ 12
MAX5091
28V, 100mA, Low-Quiescent-Current LDO
with Reset and Power-Fail Input/Output
Revision History
REVISION
NUMBER
REVISION
DATE
0
11/06
Initial release
—
1
5/14
Removed “Automotive” from the Applications section
1
DESCRIPTION
PAGES
CHANGED
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits)
shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
© 2014 Maxim Integrated Products, Inc. │ 13
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