LDO_51
IP Library: High PSRR, Low power,
80mA Low Dropout Voltage Regulator
PRODUCT PREVIEW
s
ANALOG BASEBAND REGULATOR
s
VERY LOW DROPOUT VOLTAGE : 50mV
s
HIGH PSRR : 60dB
s
LOW QUIESCENT CURRENT : 130µA
s
LOW OUTPUT VOLTAGE NOISE
s
NO CURRENT IN POWER DOWN MODE
s
SHORT CIRCUIT PROTECTION
s
SMALL DECOUPLING CERAMIC CAPACITOR
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 Analog and Mixed-signal devices for
cellular phone.
Figure 2 :
Typical Application Circuit
V
IN
IN
APPLICATION NOTE
An external capacitor (C
OUT
= 1µF) with an
equivalent serial resistance (ESR) in the range
0.02 to 0.6Ω is used for regulator stability.
Figure 1 :
Block Diagram
IN
?
? OUT
PWRDWN
?
V
REF
LDO_51
?
?
OUT
V
OUT
Power Down Mode
PWRDWN
ON
1µF
?
LDO_51
ESR
C
OUT
OFF
?
GND
June 2002
This is advance information on a new product now in development or undergoing evaluation. Details are subject to change without notice.
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LDO_51
ELECTRICAL CHARACTERISTICS
3V < V
IN
< 5.5V, -55°C < T
A
< +125°C, V
REF
= 2.8V, 0.8µF < C
OUT
< 1.2µF, 20mΩ < ESR < 0.6Ω.
100µA < I
LOAD
< 80mA.
Typical case :
V
IN
= 4V, T = 25°C, I
OUT
= 40mA.
Parameter
Input Voltage Range (Note 1)
Output Voltage
Output Voltage Accuracy
Output current
P
MOS
Output Resistance
Dropout Voltage
I
OUT
R
ON
∆V
DO
∆V
OUT
= 50mV,
I
LOAD
= 80mA
(Note 2)
Quiescent current
I
Q
I
LOAD
= 100µA
I
LOAD
= 80mA
Power down mode
quiescent current
Power Supply Rejection Ratio
PSRR
f < 10KHz
f < 100KHz
Line Regulation
Load Regulation
Line Transient
Load Transient
Lir
Ldr
Lirt
Ldtr
∆V
IN
= 300mV
t
RISE
= t
FALL
= 10µs
10% to 90%
and 90% to 10%
of 80mA in 10µs
100Hz
1KHz
100KHz
Output decoupling Capacitor
Settling time
Short Circuit Current Limit
I
SHORT
C
OUT
From power down to
active mode
180
230
1
25
300
1
mV
I
LOAD
= 80mA,
V
IN
= 3V to 5.1V
30
45
1
mV
mV
50
40
60
50
3
6
mV
dB
I
QPDM
Power down active
170
30
130
100
50
170
nA
µA
Symbol
V
IN
V
OUT
-3
0,1
Test Condition
Min
3
2,8
3
80
0,5
50
Typ
Max
5,5
Unit
V
V
%
mA
Ω
mV
Output Noise Voltage
en
1,5
550
300
µV
-----------
-
Hz
nV
-----------
-
Hz
µF
µs
mA
Notes: 1. Above characteristics are given for 3V minimum input operating range voltage, but regulator is
operational with 2.7V minimum input voltage.
2. All parameters are guaranteed with 170mV Dropout voltage.
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LDO_51
TYPICAL CHARACTERISTICS
Figure 3 :
Line transient
Figure 4 :
Settling Time
Figure 5 :
Load Transient (rising edge)
Figure 6 :
Load Transient (falling edge)
Figure 7 :
PSRR vs Frequency
(I
LOAD
max - V
IN
min)
60
Figure 8 :
Noise vs Frequency
(I
LOAD
max - V
IN
min)
650
600
550
50
500
450
NOISE (nVrms)
NOISE (nVrms)
1000
10000
100000
400
350
300
250
200
40
30
150
100
50
20
100
0
100
1000
10000
100000
FREQUENCY (Hz)
FREQUENCY (Hz)
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LDO_51
Figure 9 :
Current Consumption vs Output Current
(V
IN
= 4V)
120
CURRENT CONSUMPTION (µA)
100
80
60
40
20
0.02
0.1
10
20
30
40
50
60
70
80
OUTPUT CURRENT (mA)
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.
The ST logo is a registered trademark of STMicroelectronics
© 2002 STMicroelectronics - All Rights Reserved
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