MAXIM MAX5091BASA+

19-0654; Rev 0; 11/06
28V, 100mA, Low-Quiescent-Current LDO
with Reset and Power-Fail Input/Output
Features
♦ +5V to +28V Wide Operating Input Voltage Range
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/power-fail 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.
The MAX5091 operates over the -40°C to +125°C automotive temperature range and is available in 8-pin,
thermally enhanced TDFN and SO-EP packages.
♦ 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)
Applications
Automotive
Home Security/Safety
Industrial
Telecom/Networking
♦ Operates Over -40°C to +125°C Automotive
Temperature Range
Ordering Information
PINPACKAGE
PART
PRESET VOUT
(V)
PKG
CODE
TOP
MARK
MAX5091AATA+T
8 TDFN-8
5
T833-2
+APB
MAX5091AASA+
8 SO-EP*
5
S8E-14
—
+APC
—
MAX5091BATA+T
8 TDFN-8
3.3
T833-2
MAX5091BASA+
8 SO-EP*
3.3
S8E-14
Note: All devices specified for -40°C to +125°C operating temperature range.
+Denotes lead-free package. *EP = Exposed paddle.
Pin Configurations
Typical Application Circuit
+5V TO +28V
VIN
RH
288kΩ
TOP VIEW
+5V (MAX5091A)/
+3.3V (MAX5091B)
100mA
CIN
10μF
VS
VOUT
SO
RES
GND
8
7
6
5
VOUT
COUT
10μF
RRES
10kΩ
MAX5091
ON
MAX5091
EN
OFF
SI
μC
RESET
RES
RL
100kΩ
RSO
10kΩ
CCT
0.1μF
SO
CT
GND
EXPOSED PADDLE
+
POWERFAIL
1
2
3
4
VS
SI
EN
CT
TDFN
(3mm x 3mm)
Pin Configurations continued at end of data sheet.
________________________________________________________________ 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
MAX5091
General Description
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)
8-Pin SO-EP (derate 19.2mW/°C above +70°C) .........1538mW*
Thermal Resistance (θJA)................................................52°C/W
Thermal Resistance (θJC)..................................................6°C/W
8-Pin 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
MIN
TYP
MAX
TA = +25°C, IOUT = 1mA
CONDITIONS
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
ISHDN
Thermal-Shutdown
Temperature
TJ(SHDN)
Thermal-Shutdown
Hysteresis
ΔTJ(SHDN)
2
1mA ≤ IOUT ≤ 100mA
V
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
VEN ≤ +0.4V
17
30
µA
ILIM
IQ
0.6
UNITS
160
Temperature rising
µA
+165
°C
20
°C
_______________________________________________________________________________________
28V, 100mA, Low-Quiescent-Current LDO
with Reset and Power-Fail Input/Output
(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
Delay Comparator
Threshold
VCTTH
VCT rising
2.4
V
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
EN = low, regulator off
EN is internally pulled up to 3.6V (max)
0.4
3
V
µA
_______________________________________________________________________________________
3
MAX5091
ELECTRICAL CHARACTERISTICS (MAX5091A) (continued)
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
1mA ≤ IOUT ≤ 100mA
11
40
mV
260
400
mA
IOUT = 100µA
45
100
IOUT = 300µA
45
100
IOUT = 100mA
4.4
10
mA
VEN ≤ 0.4V
17
30
µA
ILIM
IQ
Shutdown Supply
Current
ISHDN
Thermal-Shutdown
Temperature
TJ(SHDN)
Thermal-Shutdown
Hysteresis
ΔTJ(SHDN)
160
Temperature rising
µA
+165
°C
20
°C
RESET CIRCUIT
Reset Threshold Voltage
Reset Threshold
Hysteresis
VRT
VOUT falling
VRTH
85
90
94.5
%VOUT
20
45
80
mV
55
105
Reset Pulse Delay
tRD
CCT = 100nF, tR ≥ 100µs
180
ms
RES Output-Low Voltage
VRL
VS ≥ 1.5V, RRES = 4kΩ to VOUT
0.4
V
RES Output-High
Leakage Current
IRH
VRES = 3.3V
1.0
µA
Delay Comparator
Threshold
VCTTH
2.4
V
Delay Comparator
Threshold Hysteresis
4
VCT rising
1.9
2.1
100
_______________________________________________________________________________________
mV
28V, 100mA, Low-Quiescent-Current LDO
with Reset and Power-Fail Input/Output
(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.)
VOUT AT NO LOAD, 100μA,
1mA, 10mA, 100mA
5
MAX5091 toc02
MAX5091A
MAX5091 toc01
VOUT AT NO LOAD, 100μA,
1mA, 10mA, 100mA
OUTPUT VOLTAGE vs. OUTPUT CURRENT
OUTPUT VOLTAGE vs. INPUT VOLTAGE
4
MAX5091B
MAX5091A
5.04
5.02
3
MAX5091 toc03
OUTPUT VOLTAGE vs. INPUT VOLTAGE
6
VS = 14V
4
VOUT (V)
VOUT (V)
VOUT (V)
5.00
2
4.98
4.96
3
VS = 6V
4.94
1
4.92
2
4.90
0
0
5
10
VS (V)
15
0
1
2
3
VS (V)
4
5
6
0.01
0.1
1
10
100
IOUT (mA)
_______________________________________________________________________________________
5
MAX5091
ELECTRICAL CHARACTERISTICS (MAX5091B) (continued)
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
QUIESCENT CURRENT
vs. INPUT VOLTAGE
100
4.975
IOUT = 10mA
4.950
TA = +25°C, +85°C
100
TA = -40°C
10
TA = -40°C
10
IOUT = 100mA
4.925
EN = OPEN
IOUT = 100μA
EN = OPEN
IOUT = NO LOAD
4.900
1
10
35
60
85
110
2
6
10
14 18 22
26
30
1
34 38
2
6
10
14 18 22
26
30
34 38
TEMPERATURE (°C)
VS (V)
VS (V)
RESET OUTPUT LOW
vs. TEMPERATURE
QUIESCENT CURRENT
vs. OUTPUT CURRENT
SHUTDOWN SUPPLY CURRENT
vs. INPUT VOLTAGE
10
MAX5091 toc07
0.25
RRES = 4kΩ
0.20
135
VS = 14V
TA = +25°C
40
MAX5091 toc09
-15
MAX5091 toc08
-40
VS = 14V
TA = +25°C
EN = 0V
30
0.15
ISHDN (μA)
1
IQ (mA)
RESET OUTPUT LOW (V)
TA = +125°C
TA = +125°C
IQ (μA)
VOUT (V)
TA = +25°C, +85°C
IOUT = 1mA
5.000
1000
MAX5091 toc06
IOUT = 100μA
1000
IQ (μA)
5.025
QUIESCENT CURRENT
vs. INPUT VOLTAGE
MAX5091 toc05
MAX5091A
MAX5091 toc04
5.050
0.10
RRES = 10kΩ
20
0.1
10
0.05
0.1
-40 -25 -10 5 20 35 50 65 80 95 110 125
0
100
10
20
30
DROPOUT VOLTAGE
vs. LOAD CURRENT
DROPOUT VOLTAGE
vs. LOAD CURRENT
DROPOUT VOLTAGE (mV)
16
15
14
-5
-30
65
TEMPERATURE (°C)
100
135
MAX5091A
VS = 4.75V
DROPOUT VOLTAGE (mV)
MAX5091 toc10
17
325
300
275
250
225
200
175
150
125
100
75
50
25
0
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
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
MAX5091 toc11
VS (V)
18
-40
10
IOUT (mA)
VS = 14V
EN = 0V
19
1
TEMPERATURE (°C)
20
6
0
0.01
0
ISHDN (μA)
MAX5091
28V, 100mA, Low-Quiescent-Current LDO
with Reset and Power-Fail Input/Output
1
10
IOUT (mA)
_______________________________________________________________________________________
100
28V, 100mA, Low-Quiescent-Current LDO
with Reset and Power-Fail Input/Output
IOUT = 100mA
200
150
100
50
MAX5091 toc14
4
4.54
4.52
VOUT RISING
4.50
4.48
4.44
30
65
100
0
-40
135
-5
30
65
100
SENSE OUTPUT
vs. SENSE INPUT
POWER-SUPPLY REJECTION RATIO
vs. SUPPLY CURRENT
MAX5091 toc16
5
4
VIN = 14V
IOUT = 10mA
500mVP-P
-10
1.20
1.15
1.10
VSI RISING
3
PSRR (dB)
SENSE OUTPUT (V)
1.25
VSI FALLING
2
-30
-40
-50
-60
1
SI INPUT FALLING
-70
1.00
0
65
0
-20
1.30
30
4.7
4.6
SENSE THRESHOLD
vs. TEMPERATURE
SI INPUT RISING
-5
4.5
VOUT (V)
1.40
-40
4.4
TEMPERATURE (°C)
1.45
1.05
4.3
135
TEMPERATURE (°C)
1.50
1.35
VOUT RISING
1
VOUT FALLING
MAX5091 toc17
-5
VOUT FALLING
2
4.40
-40
3
4.46
4.42
IOUT = 10mA
0
SENSE THRESHOLD (V)
4.56
MAX5091A
RRES = 10kΩ TO OUT
5
MAX5091 toc18
250
MAX5091A
4.58
VRES (V)
300
4.60
RESET THRESHOLD VOLTAGE (V)
MAX5091A
VS = 4.75V
350
DROPOUT VOLTAGE (mV)
MAX5091 toc13
400
RESET VOLTAGE
vs. OUTPUT VOLTAGE
MAX5091 toc15
RESET THRESHOLD
vs. TEMPERATURE
DROPOUT VOLTAGE
vs. TEMPERATURE
100
135
-80
1.0
1.1
TEMPERATURE (°C)
1.2
1.3
1.4
0.01
SENSE INPUT (V)
LOAD-TRANSIENT RESPONSE
10
100
LINE-TRANSIENT RESPONSE
MAX5091 toc20
VOUT
5V AC-COUPLED
200mV/div
IOUT = 1mA
VOUT
5V AC-COUPLED
100mV/div
40V
50mA
200μs/div
1
FREQUENCY (kHz)
MAX5091 toc19
CIN = 10μF
COUT = 10μF/10mΩ ESR
ISTEP = 100μA TO 50mA
0.1
IOUT
20mA/div
VS
10V/div
100μA
14V
200μs/div
_______________________________________________________________________________________
7
MAX5091
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.)
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
SHUTDOWN RESPONSE
ENABLE RESPONSE
MAX5091 toc21
MAX5091 toc23
MAX5091 toc22
IOUT = 100mA
IOUT = 10mA
VOUT
2V/div
IOUT = 100mA
VOUT
2V/div
VOUT
5V/div
0V
0V
0V
VS
5V/div
0V
0V
10ms/div
EN
2V/div
EN
5V/div
0V
200μs/div
200μs/div
Pin Description
PIN
8
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
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.
8
VOUT
EP
EP
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.
_______________________________________________________________________________________
28V, 100mA, Low-Quiescent-Current LDO
with Reset and Power-Fail Input/Output
MAX5091
LDO
PASS
ELEMENT
VS
VOUT
VINT
3μA
MAX
MAX5091
VREF
GND
ENABLE
ALWAYS-ON
EN
VOUT
ICT
2μA
PREREGULATOR
ALWAYS-ON
VINT
3.6V (MAX)
DELAY
COMPARATOR
RES
N
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
_______________________________________________________________________________________
9
MAX5091
28V, 100mA, Low-Quiescent-Current LDO
with Reset and Power-Fail Input/Output
Detailed Description
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:
tRD =
CCT × VCCTH
+ (35 × 10−6 )
ICT
where VCCTH = 2.1V and ICT = 2 × 10−6 A.
The default reset timeout period is 35µs when no
capacitor is connected from CT to ground.
10
SI/SO Comparator
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.
VTRIP =
(VST × RH )
+ VST
RL
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.
______________________________________________________________________________________
28V, 100mA, Low-Quiescent-Current LDO
with Reset and Power-Fail Input/Output
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:
2.0
8-PIN SO-EP
1.8
1.538W
1.6
IOUT(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.
Table 1. Recommended Output Capacitor
ESR
RECOMMENDED COUT ESR
1.4
PD (W)
MAX5091 fig02
1.538W For TA ≤ + 70°C
⎧
PD = ⎨
⎩1.538 − 0.01923 (TA − 70° C) For + 70° C < TA ≤ + 125°C
After determining the allowable package dissipation, calculate the maximum output current using the following
formula:
DERATE
19.23mW/°C
IOUT
VOUT = 3.3V
1.0
IOUT ≤ 10mA
CESR < 0.66Ω
CESR < 1Ω
0.8
IOUT ≤ 50mA
CESR < 0.132Ω
CESR < 0.2Ω
0.6
IOUT ≤ 100mA
CESR < 66mΩ
CESR < 0.1Ω
1.2
VOUT = 5.0V
0.4
0.2
0
10
20
30
40
70
90 110 130 150
60
80 100 120 140
TEMPERATURE (°C)
50
Figure 2. 8-Pin SO-EP Maximum Power Dissipation vs.
Temperature
______________________________________________________________________________________
11
MAX5091
Applications Information
28V, 100mA, Low-Quiescent-Current LDO
with Reset and Power-Fail Input/Output
MAX5091
Pin Configurations (continued)
Chip Information
PROCESS: BiCMOS
TOP VIEW
VS
1
SI
2
+
8
VOUT
7
SO
6
RES
5
GND
MAX5091
EN
3
CT 4
EXPOSED PADDLE
SO-EP
12
______________________________________________________________________________________
28V, 100mA, Low-Quiescent-Current LDO
with Reset and Power-Fail Input/Output
8L, SOIC EXP. PAD.EPS
PACKAGE OUTLINE
8L SOIC, .150" EXPOSED PAD
21-0111
C
1
______________________________________________________________________________________
1
13
MAX5091
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 Information (continued)
(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.)
6, 8, &10L, DFN THIN.EPS
MAX5091
28V, 100mA, Low-Quiescent-Current LDO
with Reset and Power-Fail Input/Output
PACKAGE OUTLINE, 6,8,10 & 14L,
TDFN, EXPOSED PAD, 3x3x0.80 mm
21-0137
14
______________________________________________________________________________________
H
1
2
28V, 100mA, Low-Quiescent-Current LDO
with Reset and Power-Fail Input/Output
COMMON DIMENSIONS
PACKAGE VARIATIONS
SYMBOL
MIN.
MAX.
PKG. CODE
N
D2
E2
e
JEDEC SPEC
b
A
0.70
0.80
T633-1
6
1.50±0.10
2.30±0.10
0.95 BSC
MO229 / WEEA
0.40±0.05
1.90 REF
D
2.90
3.10
T633-2
6
1.50±0.10
2.30±0.10
0.95 BSC
MO229 / WEEA
0.40±0.05
1.90 REF
[(N/2)-1] x e
E
2.90
3.10
T833-1
8
1.50±0.10
2.30±0.10
0.65 BSC
MO229 / WEEC
0.30±0.05
1.95 REF
A1
0.00
0.05
T833-2
8
1.50±0.10
2.30±0.10
0.65 BSC
MO229 / WEEC
0.30±0.05
1.95 REF
L
0.20
0.40
T833-3
8
1.50±0.10
2.30±0.10
0.65 BSC
MO229 / WEEC
0.30±0.05
1.95 REF
T1033-1
10
1.50±0.10
2.30±0.10
0.50 BSC
MO229 / WEED-3
0.25±0.05
2.00 REF
k
0.25 MIN.
A2
0.20 REF.
T1033-2
10
1.50±0.10
2.30±0.10
0.50 BSC
MO229 / WEED-3
0.25±0.05
2.00 REF
T1433-1
14
1.70±0.10
2.30±0.10
0.40 BSC
----
0.20±0.05
2.40 REF
T1433-2
14
1.70±0.10
2.30±0.10
0.40 BSC
----
0.20±0.05
2.40 REF
PACKAGE OUTLINE, 6,8,10 & 14L,
TDFN, EXPOSED PAD, 3x3x0.80 mm
-DRAWING NOT TO SCALE-
21-0137
H
2
2
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 ____________________ 15
© 2006 Maxim Integrated Products
Heaney
is a registered trademark of Maxim Integrated Products, Inc.
MAX5091
Package Information (continued)
(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.)