19-2018; Rev 0; 4/01
500mA, Low-Voltage Linear Regulator in µMAX
General Description
The MAX1806 low-dropout linear regulator operates
from a +2.25V to +5.5V supply and delivers a guaran-
teed 500mA load current with low 175mV dropout. The
high-accuracy (±1%) output voltage is preset at an
internally trimmed voltage (see
Selector Guide)
or can
be adjusted from +0.8V to +4.5V with an external resis-
tive-divider.
An internal PMOS pass transistor allows low 210µA
supply current, making this device ideal for portable
equipment such as personal digital assistants (PDAs),
cellular phones, cordless phones, and other equip-
ment, including base stations and docking stations.
Other features include an active-low, power-OK output
that indicates when the output is out of regulation, a
0.02µA shutdown mode, short-circuit protection, and
thermal shutdown protection. The MAX1806 comes in a
miniature 1.3W, 8-pin power-µMAX package with a
metal pad on the underside of the package.
o
Guaranteed 500mA Output Current
o
Output Down to 0.8V
o
Low 175mV Dropout at 500mA
o
±1% Output Voltage Accuracy
Preset at 0.8V, 1.5V, 1.8V, 2.5V, or 3.3V
Adjustable from 0.8V to 4.5V
o
Power-OK Output
o
Low 210µA Ground Current
o
0.02µA Shutdown Current
o
Thermal Overload Protection
o
Output Current Limit
o
Tiny 1.3W, 8-Pin Power-µMAX Package
Features
MAX1806
Ordering Information
PART
MAX1806EUA_
_
TEMP. RANGE
-40°C to +85°C
PIN-PACKAGE
8 Power-µMAX
Applications
Notebook Computers
Cellular and Cordless Telephones
PDAs
Palmtop Computers
Base Stations
USB Hubs
Docking Stations
Selector Guide
PART AND SUFFIX
MAX1806EUA33
MAX1806EUA25
MAX1806EUA18
MAX1806EUA15
MAX1806EUA08
V
OUT
(V)
3.3
2.5
1.8
1.5
0.8
TOP MARK
AAAG
AAAH
AAAI
AAAJ
AAAK
Typical Operating Circuit
V
IN
+2.25V TO +5.5V
IN
NC
C
IN
1µF
R
POK
100kΩ
POK
TO
µC
OUT
C
OUT
10µF
V
OUT
0.8V TO 4.5V
Pin Configuration
TOP VIEW
IN
1
IN
2
8
7
OUT
OUT
SET
GND
MAX1806
ON
SHDN
OFF
MAX1806
POK
3
6
5
SHDN
4
SET
GND
µMAX
________________________________________________________________
Maxim Integrated Products
1
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.
500mA, Low-Voltage Linear Regulator in µMAX
MAX1806
ABSOLUTE MAXIMUM RATINGS
IN,
SHDN,
POK, SET to GND ...................................-0.3V to +6V
OUT to GND ................................................-0.3V to (V
IN
+ 0.3V)
Output Short-Circuit Duration.....................................Continuous
Continuous Power Dissipation (T
A
= +70°C)
8-Pin Power-µMAX (derate 17mW/°C above +70°C) .......1.3W
Operating Temperature .......................................-40°C to +85°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
(V
IN
= V
OUT(SETPOINT)
+ 500mV or V
IN
= +2.25V whichever is greater, SET = GND,
SHDN
= IN,
T
A
= 0°C to +85°C,
unless otherwise
noted. Typical values are at T
A
= +25°C.)
PARAMETER
Input Voltage
Input Undervoltage Lockout
Output Voltage Accuracy
(Preset Mode)
Adjustable Output Voltage
T
A
= +85°C, I
OUT
= 100mA
SET Voltage Threshold
(Adjustable Mode)
Maximum Output Current
Short-Circuit Current Limit
SET Dual Mode
™
Threshold
SET Input Bias Current
Ground-Pin Current
I
SET
I
Q
V
SET
= +0.8V
I
OUT
= 1mA
I
OUT
= 500mA
V
OUT
= +2.25V
Dropout Voltage (Note 1)
Line Regulation
Load Regulation
Output Voltage Noise
SHUTDOWN
Shutdown Supply Current
SHDN
Input Threshold
SHDN
Input Bias Current
Startup Time
I
OFF
V
IH
V
IL
I
SHDN
T
START
SHDN
= GND or IN
C
OUT
= 10µF, time from
SHDN
high to POK high
10
40
SHDN
= GND, V
IN
= 5.5V
1.6
0.6
100
0.02
5
µA
V
nA
µs
∆V
LNR
∆V
LDR
I
OUT
= 500mA
V
OUT
= +2.8V
V
OUT
= +4.0V
V
IN
from (V
OUT
+ 100mV) to 5.5V, I
LOAD
= 5mA
I
OUT
= 1mA to 500mA
10Hz to 1MHz, C
OUT
= 10µF (ESR < 0.1Ω)
V
SET
T
A
= +85°C, I
OUT
= 1mA to 500mA
T
A
= 0°C to +85°C, I
OUT
= 1mA to 500mA,
V
IN
> V
OUT
+ 0.5V
V
OUT
= 0V
SYMBOL
V
IN
V
UVLO
Rising, 40mV hysteresis
T
A
= +85°C, I
OUT
= 100mA
V
OUT
T
A
= +85°C, I
OUT
= 1mA to 500mA
T
A
= 0°C to +85°C, I
OUT
= 1mA to 500mA,
V
IN
> V
OUT
+ 0.5V
CONDITIONS
MIN
2.25
1.85
-1
-1.5
-3
0.8
790
786
774
500
700
35
-100
210
575
259
201
147
0
15.5
300
384
315
255
0.125
35
%/V
ppm/mA
µV
RMS
mV
1400
80
2300
125
+100
400
800
2.0
TYP
MAX
5.5
2.15
+1
+1.5
+3
4.5
810
814
826
mA
RMS
mA
mV
nA
µA
mV
V
%
UNITS
V
V
I
OUT
I
LIM
Dual Mode is a trademark of Maxim Integrated Products, Inc.
2
_______________________________________________________________________________________
500mA, Low-Voltage Linear Regulator in µMAX
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
OUT(SETPOINT)
+ 500mV or V
IN
= +2.25V whichever is greater, SET = GND,
SHDN
= IN,
T
A
= 0°C to +85°C,
unless otherwise
noted. Typical values are at T
A
= +25°C.)
PARAMETER
POWER-OK
POK Output Low Voltage
Operating Voltage Range for
Valid POK Output
Output High-Leakage Current
Threshold
THERMAL PROTECTION
Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
T
SHDN
∆T
SHDN
170
20
°C
°C
V
OL
Sinking 2mA
Sinking 100µA
V
POK
= +5.5V
Rising edge, referred to V
OUT(NOMINAL)
90
93
1.0
5
50
5.5
100
96
mV
V
nA
%
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX1806
ELECTRICAL CHARACTERISTICS
(V
IN
= V
OUT(SETPOINT)
+ 500mV or V
IN
= +2.25V whichever is greater, SET = GND,
SHDN
= IN,
T
A
= -40°C to +85°C,
unless other-
wise noted. Typical values are at T
A
= +25°C.) (Note 2)
PARAMETER
Input Voltage
Input Undervoltage Lockout
Output Voltage Accuracy
(Preset Mode)
Adjustable Output Voltage
SET Voltage Threshold
(Adjustable Mode)
Maximum Output Current
Short-Circuit Current Limit
SET Dual Mode
™
Threshold
SET Input Bias Current
Ground-Pin Current
Dropout Voltage (Note 1)
Line Regulation
Load Regulation
SHUTDOWN
Shutdown Supply Current
SHDN
Input Threshold
SHDN
Input Bias Current
I
OFF
V
IH
V
IL
I
SHDN
SHDN
= GND, V
IN
= 5.5V
2.5V < V
IN
< 5.5V
2.5V < V
IN
< 5.5V
SHDN
= GND or IN
1.6
0.6
100
5
µA
V
nA
∆V
LNR
∆V
LDR
I
SET
I
Q
V
SET
= +0.8V
I
OUT
= 1mA
V
OUT
= +2.25V
I
OUT
= 500mA
V
OUT
= +2.8V
V
OUT
= +4.0V
V
IN
from (V
OUT
+ 100mV) to 5.5V, I
LOAD
= 5mA
I
OUT
= 1mA to 500mA
-0.175
259
201
147
V
SET
I
OUT
I
LIM
V
OUT
= 0V
I
OUT
= 1mA to 500mA
SYMBOL
V
IN
V
UVLO
V
OUT
Rising, 40mV hysteresis
I
OUT
= 1mA to 500mA
CONDITIONS
MIN
2.25
1.85
-4
0.8
766
500
700
35
-100
2500
125
+100
400
384
315
255
+0.175
35
%/V
ppm/mA
mV
TYP
MAX
5.5
2.15
+4
4.5
834
UNITS
V
V
%
V
mV
mA
RMS
mA
mV
nA
µA
_______________________________________________________________________________________
3
500mA, Low-Voltage Linear Regulator in µMAX
MAX1806
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
OUT(SETPOINT)
+ 500mV or V
IN
= +2.25V whichever is greater, SET = GND,
SHDN
= IN,
T
A
= -40°C to +85°C,
unless other-
wise noted. Typical values are at T
A
= +25°C.) (Note 2)
PARAMETER
POWER-OK
POK Output Low Voltage
Operating Voltage Range for
Valid POK Output
Output High-Leakage Current
Threshold
V
OL
Sinking 2mA
Sinking 100µA
V
POK
= +5.5V
Rising edge, referred to V
OUT(NOMINAL)
89
1.0
50
5.5
100
97
mV
V
nA
%
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Note 1:
Dropout voltage is defined as V
IN
- V
OUT
, when V
OUT
is 100mV below the value of V
OUT
and when V
IN
= V
OUT(NOM)
+0.5V.
For 2.25V
≤
V
OUT
≤
4.0V, dropout voltage limits are linearly interpolated from the values listed. For V
OUT
< 4.0V, dropout
voltage limit is equal to the value for V
OUT
= 4.0V.
Note 2:
Specifications to -40°C are guaranteed by design, not production tested.
Typical Operating Characteristics
(MAX1806EUA33, V
IN
= V
OUT
+ 500mV,
SHDN
= IN, C
IN
= 1µF, C
OUT
= 10µF, T
A
= +25°C, unless otherwise noted.)
OUTPUT VOLTAGE vs. INPUT VOLTAGE
MAX1806 toc01
OUTPUT VOLTAGE vs. LOAD CURRENT
MAX1806 toc02
OUTPUT VOLTAGE vs. TEMPERATURE
V
IN
= V
OUT
+ 500mV
I
OUT
= 0
MAX1806 toc03
3.5
I
OUT
= 0mA
3.0
OUTPUT VOLTAGE (V)
2.5
2.0
1.5
1.0
0.5
0
I
OUT
= 500mA
3.32
3.31
OUTPUT VOLTAGE (V)
3.30
3.29
3.28
3.27
3.26
3.25
3.34
3.33
OUTPUT VOLTAGE (V)
3.32
3.31
3.30
3.29
3.28
1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
INPUT VOLTAGE (V)
0
100 200 300 400 500 600 700 800
LOAD CURRENT (mA)
-40
-15
10
35
60
85
TEMPERATURE (°C)
DROPOUT VOLTAGE vs. LOAD CURRENT
350
DROPOUT VOLTAGE (mV)
300
250
200
150
100
50
0
0
100 200 300 400 500 600 700 800
LOAD CURRENT (mA)
T
A
= -40°C
T
A
= +25°C
T
A
= +85°C
MAX1806 toc04
DROPOUT VOLTAGE vs.
OUTPUT VOLTAGE
0.28
DROPOUT VOLTAGE (V)
0.26
0.24
0.22
0.20
0.18
0.16
0.14
2.0
2.5
3.0
3.5
4.0
4.5
OUTPUT VOLTAGE (V)
600
550
500
450
400
350
300
250
200
150
100
50
0
2.0
MAX1806 toc05
GROUND-PIN CURRENT vs.
INPUT VOLTAGE
MAX1806 toc06
400
GROUND-PIN CURRENT (µA)
I
OUT
= 500mA
I
OUT
= 0mA
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
INPUT VOLTAGE (V)
4
_______________________________________________________________________________________
500mA, Low-Voltage Linear Regulator in µMAX
MAX1806
Typical Operating Characteristics (continued)
(MAX1806EUA33, V
IN
= V
OUT
+ 500mV,
SHDN
= IN, C
IN
= 1µF, C
OUT
= 10µF, T
A
= +25°C, unless otherwise noted.)
GROUND-PIN CURRENT vs.
LOAD CURRENT
MAX1806 toc07
450
GROUND-PIN CURRENT (µA)
400
350
300
250
200
150
100
0
V
IN
= 5.5V
V
IN
= 3.8V
V
IN
= V
OUT
+ 500mV
I
OUT
= 0
MAX1806 toc08
GROUND-PIN CURRENT (µA)
190
-50
-40
180
PSRR (dB)
-30
-20
170
160
-10
0
-40
-15
10
35
60
85
TEMPERATURE (°C)
150
100 200 300 400 500 600 700 800
LOAD CURRENT (A)
C
OUT
= 10µF
I
OUT
= 50mA
0.01
0.1
1
10
100
1000
FREQUENCY (kHz)
OUTPUT SPECTRAL NOISE DENSITY
vs. FREQUENCY
OUTPUT SPECTRAL NOISE DENSITY (µV/
√
Hz)
C
OUT
= 10µF
I
OUT
= 50mA
MAX1806 toc10
OUTPUT NOISE DC TO 1MHz
MAX1806 toc11
10
1
0.1
V
OUT
1mV/div
0.01
V
OUT
= 3.3V
R
OUT
= 66Ω (50mA)
0.1
1
10
FREQUENCY (kHz)
100
1000
20ms/div
0.001
REGION OF STABLE C
OUT
ESR
vs. LOAD CURRENT
MAX1806 toc12
LOAD-TRANSIENT RESPONSE
MAX1806 toc13
100
REGION OF C
OUT
ESR
10
C
OUT
= 10µF
1
STABLE REGION
0.1
V
IN
= V
OUT
+ 500mV
C
IN
= 10µF
R
OUT
= 660Ω TO 6.6Ω (5mA TO 500mA)
0
100 200 300 400 500 600 700 800
FREQUENCY (kHz)
10µs/div
I
OUT
200mA/div
V
OUT
20mV/div
0.01
_______________________________________________________________________________________
MAX1806 toc09
500
GROUND-PIN CURRENT vs.
TEMPERATURE
200
-60
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
5
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