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June 2002
IP Library: High Output Current, Low power,
400mA Low Dropout Voltage Regulator
s
DIGITAL BASEBAND REGULATOR
s
VERY LOW DROPOUT VOLTAGE : 50mV
s
HIGH OUTPUT CURRENT : 400mA
s
LOW QUIESCENT CURRENT : 100
A
s
HIGH PSRR : 60dB
s
LOW OUTPUT VOLTAGE NOISE
s
NO CURRENT IN POWER DOWN MODE
s
SHORT CIRCUIT PROTECTION
TYPICAL APPLICATIONS
Cellular and Cordless phones supplied by 1 cell
Lithium-ion battery / 3 cells Ni-MH or Ni-Cd
battery.
PDA (Personal Digital Assistant), Smart phone.
Portable equipment.
Supply for Digital Baseband devices for cellular
phone.
APPLICATION NOTE
An external capacitor (C
OUT
= 4.7
F) with an
equivalent serial resistance (ESR) in the range
0.02 to 0.6
is used for regulator stability.
Figure 1 : Block Diagram
?
V
REF
?
?
?
LDO_57
OUT
IN
PWRDWN
STDBY
Figure 2 : Typical Application Circuit
4.7
F
ESR
V
OUT
C
OUT
?
?
OUT
GND
?
?
?
V
IN
IN
PWRDWN
Power Down Mode
OFF
ON
Stand-by Mode
STDBY
Active Mode
LDO_57
Stand-by Mode
LDO_57
This is advance information on a new product now in development or undergoing evaluation. Details are subject to change without notice.
PRODUCT PREVIEW
LDO_57
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ELECTRICAL CHARACTERISTICS
3V < V
IN
< 5.5V, -30C < T
A
< +85C, V
REF
= 2.8V, C
OUT
= 4.7
F 20%, 20m
< ESR < 0.6
,
I
LOAD
= 400mA.
Typical case : V
IN
= 4V, T = 25C, C
OUT
= 4.7
F, I
LOAD
= 400mA.
Notes: 1. Above characteristics are given for 2.9V minimum input operating range voltage, but regulator
is operational with 2.7V minimum input voltage.
2. All performances of the regulator are guarenteed for a voltage drop of 170mV minimum.
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
Input Voltage Range (Note 1)
V
IN
2,9
5,5
V
Output Voltage
V
OUT
1,8
4,9
V
Output Voltage Accuracy
3
%
Output current
I
OUT
400
mA
Dropout Voltage
V
DO
V
OUT
= 50mV,
I
LOAD
= 400mA,
50
mV
(Note 2)
170
mV
Quiescent current
I
Q
I
LOAD
= 100
A
100
150
A
I
LOAD
= 40mA
150
230
I
LOAD
= 400mA
350
450
Power down mode quiescent current
I
QPDM
Power down active
100
nA
Power Supply Rejection Ratio
PSRR
DC
40
60
dB
f = 10KHz
40
55
Line Regulation
Lir
I
LOAD
= 400mA,
V
IN
= 2.9V to 5.5V
4
mV
Load Regulation
Ldr
I
LOAD
= 100
A - 400mA
50
55
mV
Line Transient
Lirt
V
IN
= 300mV
t
RISE
= t
FALL
= 10
s
2,5
5
mV
Load Transient
Ldtr
I
LOAD
= 100
A - 400mA
in 10
s
3
5
mV
Output Noise Voltage
en
100Hz
1,2
1KHz
400
10KHz
140
en
RMS
BW : 100Hz to 100KHz
35
V
RMS
Output decoupling Capacitor
C
OUT
4,7
F
Settling time
From power down
to active mode
50
s
Short Circuit Current Limit
I
SHORT
2
A
V
Hz
------------
nV
Hz
------------
LDO_57
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1
10
100
1000
10000
100000
1000000
-70
-60
-50
-40
-30
-20
FREQUENCY (Hz)
PS
R
R
(
d
B
)
150m V
170m V
200m V
2V
ELECTRICAL CHARACTERISTICS : (Stand-by mode)
3V < V
IN
< 5.5V, -30C < T
A
< +85C, V
REF
= 2.8V, C
OUT
= 4.7
F 20%, 20m
< ESR < 0.6
,
I
LOAD
= 500
A.
Typical case : V
IN
= 4V, Ambient temperature, I
LOAD
= 500
A.
TYPCIAL CHARACTERISTICS
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
Output current in stand-by mode
I
OUTSTDBY
500
A
Quiescent Current in stand-by mode
I
STDBY
I
LOAD
= 500
A
20
30
Power Supply Rejection Ratio
in stand-by mode
PSRR
STY
f = 10KHz
35
45
dB
Line Regulation in stand-by mode
Lir
STDBY
I
LOAD
= 500
A,
V
IN
= 2.9V to 5.5V
2
6
mV
Load Regulation
Ldr
STDBY
I
LOAD
= 100
A - 500
A 50
55
mV
Figure 7 : PSRR vs Frequency
for Various Voltage Drop
LDO_57
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Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the
consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from
its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications
mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information
previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or
systems without express written approval of STMicroelectronics.
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