MAXIM MAX4836, MAX4837 User Manual
General Description
The MAX4836/MAX4837 family of low-dropout (LDO)
linear regulators feature an accurate current-limiting
switch with an integrated FLAG or RESET function. These
devices operate from 2.5V to 5.5V and deliver up to
500mA of load current at a preset output voltage. Preset
output voltage levels are 1.8V/2.5V/2.8V/3.0V/3.3V.
The MAX4836/MAX4837 offer a programmable softstart control function to eliminate false reset during
startup. The MAX4836 provides a FLAG function to notify the system when the load current exceeds the limit.
The MAX4837 provides a RESET function to notify the
system when the output drops below the threshold.
Additionally, reverse-current protection prevents current flowing from the output to the input. Other features
include a low 90µA quiescent current, a 0.1µA shutdown current.
The MAX4836/MAX4837 are available in space-saving
6-pin SOT23 and TDFN packages. Each device is specified over the -40°C to +85°C extended temperature
range. Contact factory for other programmed output voltage versions from 1.5V to 3.3V in 100mV increments.
For pin-compatible 100mA versions of this device, refer
to the MAX4832/MAX4833. For pin-compatible 250mA
versions of this device, refer to the MAX4834/MAX4835.
Applications
SDIO Ports and Devices Notebook Computers
USB Ports and Devices Cell Phones
PDAs and Palmtop Devices GPS Systems
Features
♦ Guaranteed Minimum 500mA Load Current
♦ Accurate Current Limit
♦ Preset Output Voltages: 1.8V/2.5V/2.8V/3.0V/3.3V
♦ 2.5V to 5.5V Supply Voltage Range
♦ Adjustable Soft-Start
♦ Low Dropout Voltage
♦ Thermal Shutdown
♦ Reverse-Current Protection
♦ Shutdown Output Discharge (MAX4837)
♦ Low 90µA Supply Current
♦ Ultra-Low 0.1µA Shutdown Current
♦ FLAG and Latch Off (MAX4836) or RESET
(MAX4837)
♦ Tiny SOT23 and TDFN (3mm x 3mm) Packages
MAX4836/MAX4837
500mA LDO Linear Regulators with
Current-Limiting Switch
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
19-3374; Rev 0; 7/04
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
Note: “xy” are placeholders for the output voltage levels of the
devices. Insert the values found in Table 1 at the end of this document in the place of “xy”. The “_” is a placeholder for either the
RESET
or the
FLAG
feature. Insert “B” in the place of “_” for
RESET
and “C” for
FLAG
. “dd” is a placeholder for the reset
timeout period. Insert the values found in Table 2 in the place of
“dd.” For example, MAX4837EUT18BD2 has a 1.8V output voltage,
RESET
feature, and a 30ms reset timeout period. Note that
“dd” applies only to the devices with
RESET
option and does not
apply to the devices with
FLAG
option. For devices with the
FLAG
option, leave dd blank. Standard versions require a minimum order increment of 2.5k units. Nonstandard versions must
be ordered in 10k unit increments. Contact factory for availability.
*Future product—contact factory for availability.
Pin Configurations
Pin Configurations continued at end of data sheet.
Tables 1 and 2 and Selector Guide appear at end of data
sheet.
TOP VIEW
1
IN
2
GND
SHDN
( ) MAX4836ETTxyC ONLY.
MAX4836/MAX4837
3
EXPOSED PADDLE
TDFN
OUT
6
5
SS
RESET
4
(FLAG)
PART TEMP RANGE PIN-PACKAGE
MAX4836EUTxy_-T* -40°C to +85°C 6 SOT23-6
MAX4836ETTxy_-T -40°C to +85°C 6 TDFN-6
MAX4837EUTxy_dd-T* -40°C to +85°C 6 SOT23-6
MAX4837ETTxy_dd-T -40°C to +85°C 6 TDFN-6
MAX4836/MAX4837
500mA LDO Linear Regulators with
Current-Limiting Switch
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VIN= V
OUT
+ 1V, SHDN = IN, C
OUT
= 3.3µF, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
IN, SHDN, FLAG, OUT to GND ................................-0.3V to +6V
RESET to GND .........................................-0.3V to (V
OUT
+ 0.3V)
SS to GND ...................................................-0.3V to (V
IN
+ 0.3V)
IN to OUT ...............................................................................±6V
OUT Short Circuit to GND ..........................................Continuous
All Pins ESD Handling (Human Body Model).........................2kV
Continuous Power Dissipation (T
A
= +70°C)
6-Pin SOT23 (derate 9.1mW/°C above +70°C)................727mW
6-Pin TDFN (derate 24.4mW/°C above +70°C) ..........1951.2mW
Operating Temperature Range ...........................-40°C to +85°C
Operating Junction Temperature Range...........-40°C to +125°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Operating Voltage V
Input Undervoltage Lockout
Threshold
Input Undervoltage Lockout
Threshold Hysteresis
Quiescent Current I
Dropout Voltage (Note 2) I
Output Voltage Accuracy
Output Current I
Output Current Limit V
Reverse Current at V
Soft-Start Time (Note 3) t
Line Regulation (Note 4)
Load Regulation 100µA < I
Output Noise 10Hz to 100kHz, C
SHUTDOWN INPUT (SHDN)
OUT Discharge Resistance in
Shutdown (MAX4837)
SHDN Input-Voltage High V
SHDN Input-Voltage Low V
SHDN Input Hysteresis 30 mV
SHDN Input Leakage Current SHDN = IN or GND -100 +100 nA
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
IN
IN
V
UVLO
OUT
SS
VIN rising 2.00 2.25 V
Q
SHDN = IN, I
SHDN = IN, I
V
< VIN < V
UVLO
SHDN = GND, I
= 500mA
OUT
I
= 1mA to 500mA, TA = +25°C -1.3 +1.3
OUT
I
= 1mA to 500mA, TA = -40°C to +85°C -2 +2
OUT
= 0V 540 660 mA
OUT
V
= 5.5V, V
OUT
C
= not connected 0.5 1 2.0
SS
C
= 0.01µF 4 10 15
SS
C
= 0.1µF 40 100 150
SS
V
+ 0.5V < V
OUT
5.5V, I
LOAD
= 0 90 150
OUT
= 0,
OUT
(nominal)
OUT
= 0 0.1 2
OUT
TA = +25°C 200 300
T
= -40°C to +85°C 330
A
= 0V to V
IN
IN
= 100µA
< 500mA, VIN = V
LOAD
OUT
TA = +25°C -0.04 +0.02 +0.065
<
T
= -40°C to +85°C -0.05 +0.03 +0.08
A
+ 1V 1.3 %V
OUT
= 0.01µF 70 µV
SS
SHDN = GND 900 Ω
IH
IL
2.5 5.5 V
50 mV
150
500 mA
0.1 2 µA
1.4 V
0.5 V
%V
%V
µA
mV
NOM
ms
NOM
V
NOM
RMS
/
MAX4836/MAX4837
500mA LDO Linear Regulators with
Current-Limiting Switch
_______________________________________________________________________________________ 3
Note 1: Parts are 100% tested at +25°C. Limits across the full temperature range are guaranteed by design and correlation over the
specified temperature range.
Note 2: The dropout voltage is measured from V
IN
to V
OUT
when V
OUT
is 2% below its nominal value. The nominal output voltage is
measured from V
OUT
to GND when VINis 1V greater than V
OUT
. Defined only for V
OUT
≥ 2.5V.
Note 3: Soft-start time is defined as the time required for the output to rise from 10% of its nominal value to 90% of its nominal value.
Note 4: For V
OUT
< 2V, VINmust be above 2.5V.
Note 5: This is the maximum time OUT can be out of tolerance before a reset is issued. It is implemented to ensure that momentary
output glitches do not trigger a reset condition.
Note 6: In startup mode, the blanking time counter is not started until the soft-start time has elapsed. The total time from startup to
FLAG issued is t
SS
+ t
BLANK
.
ELECTRICAL CHARACTERISTICS (continued)
(VIN= V
OUT
+ 1V, SHDN = IN, C
OUT
= 3.3µF, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
RESET OUTPUT (MAX4837)
RESET Threshold V
OUT Drop to RESET Delay
(Note 5)
RESET Timeout Period t
RESET Output-Voltage Low
RESET Output-Voltage High
FLAG OUTPUT (MAX4836)
Blanking Time (Note 6) t
Open-Drain FLAG Output-
Voltage Low
Open-Drain FLAG Leakage
Current
THERMAL PROTECTION
Thermal-Shutdown Temperature Junction temperature rising +165 °C
Thermal-Shutdown Hysteresis 15 °C
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
RESET
t
OR
RESET
BLANK
0.85 x
V
D1 timing option 2.5 3.75 5.0
D2 timing option 20 30 40
D3 timing option 150 225 300
D4 timing option 1200 1800 2400
V
≥ 1.0V, I
OUT
V
≥ 1.5V, I
OUT
asserted
V
≥ 2.0V, I
OUT
RESET deasserted
V
+ 1V ≤ VIN ≤ 5.5V, OUT = GND 5 10 17 ms
OUT
I
= 3.2mA, FLAG asserted, V
SINK
V
= 5.5V 0.01 1 µA
FLAG
= 50µA, RESET asserted 0.3
SINK
= 3.2mA, RESET
SINK
SOURCE
≤ 500µA,
≥ 1.5V 0.4 V
OUT
0.8 x
V
OUT
OUT
0.875 x
V
0.90 x
V
OUT
35 µs
OUT
0.4
V
ms
V
V
MAX4836/MAX4837
500mA LDO Linear Regulators with
Current-Limiting Switch
4 _______________________________________________________________________________________
Typical Operating Characteristics
(VIN= V
OUT
+ 1V, SHDN = IN, C
OUT
= 3.3µF, TA= +25°C, unless otherwise noted.)
QUIESCENT CURRENT vs. INPUT VOLTAGE
(NO LOAD)
MAX4836 toc01
VIN (V)
I
Q
(µA)
54321
20
40
60
80
100
120
0
06
TA = +85°C
TA = -40°C
TA = +25°C
V
OUT
= 1.5V
QUIESCENT CURRENT vs. INPUT VOLTAGE
(500mA LOAD)
MAX4836 toc02
VIN (V)
I
Q
(µA)
5432106
TA = +85°C
V
OUT
= 3.3V
TA = -40°C
100
200
300
400
500
600
700
800
0
TA = +25°C
MAXIMUM TRANSIENT DURATION
vs. RESET THRESHOLD OVERDRIVE
MAX4836 toc03
RESET THRESHOLD OVERDRIVE (mV)
PULSE DURATION (µs)
10
15
30
45
60
75
90
0
1100
RESET ASSERTS
ABOVE THIS LINE
VIN = 3.5V
V
OUT
= 2.5V
DROPOUT VOLTAGE vs. LOAD CURRENT
MAX4836 toc04
LOAD CURRENT (mA)
DROPOUT VOLTAGE (mV)
400300200100
30
60
90
120
150
180
0
0500
V
OUT
= 3.3V
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
MAX4836 toc05
FREQUENCY (kHz)
PSRR (dB)
1010.1
-70
-60
-50
-40
-30
-20
-10
0
-80
0.01 100
V
OUT
= 2V
C
OUT
= 3.3µF
I
LOAD
= 20mA
REGION OF STABLE C
OUT
ESR
vs. LOAD CURRENT
MAX4836 toc06
LOAD CURRENT (mA)
C
OUT
ESR (Ω)
1
2
3
4
5
6
7
0
V
OUT
= 1.8V
C
OUT
= 3.3µF
STABLE REGION
450400350300250200150100500500
OUTPUT NOISE vs. FREQUENCY
MAX4836 toc07
FREQUENCY (Hz)
OUTPUT NOISE (µV
RMS
)
10k1k100
10
20
30
40
50
0
10 100k
VIN = 3V
V
OUT
= 1.8V
C
SS
= 10nF
I
LOAD
= 0
SOFT-START RESPONSE
(C
SS
= FLOATING)
MAX4836 toc08
V
SS
1V/div
V
OUT
2V/div
V
IN
2V/div
2ms/div
t
SS
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