SGS Thomson Microelectronics LDO-55 Datasheet
1/2June 2002
IP Library: Very Low Power, Adjustable Output Voltage² ,
25mA Low Dropout Volt age Regulator
■
ANALOG BASEBAND REGUL AT OR
■
VERY LOW DROPOUT VOLTAGE : 60mV
■
HIGH PSRR : 60dB
■
LOW QUIESCENT CURRENT
■
20µA STD-BY MODE CURRENT
■
NO CURRENT IN POWER DOWN MODE
■
SHORT CIRCUIT PROTECTION
■
SMALL DECOUPLING CERAMIC CAPACITOR
TYPICAL APPLICATIONS
– Cellular and Cordless phones suppli ed by 1 cell
Lithium-ion battery / 3 cells Ni-MH or Ni-Cd
battery.
– PDA (Personal Digital Assistant), Smart phone.
– Portable equipm ent.
– Supply for Digital (DSP/Microcontroller) devices.
APPLICATION NOTE
An external capacitor (C
OUT
= 1µF typical) with an
equivalent serial resistance (ESR) in the range
0.02 to 0.6Ω is used to ensure stability.
Figure 1 :
Block Diagram
?
V
REF
?
?
?
LDO_55
OUTIN
PWRDWN
STDBY
Figure 2 :
Typical Application Circuit
1µF
ESR1
V
OUT
C
OUT
?
?
OUT
GND
?
?
?
V
IN
IN
PWRDWN
Power Down Mode
OFF
ON
Stand-by Mode
STDBY
Active Mode
LDO_55
→
→
Stand-by Mode
→
→
LDO_55
This is advance information on a new product now in development or undergoing evaluation. Details are subject to change without notice.
PRODUCT PREVIEW
LDO_55
2/2
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mentioned in this publication ar e subject to change without notice. This publication supersedes and replaces all information
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systems without express written approval of STMicroelectronics.
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ELECTRICAL CHARACTERISTICS
3V < V
IN
< 5.5V, -30°C < T < +125°C, 0.8µF < C
OUT
< 1.2µF, 20mΩ < ESR < 0.6Ω, 100µA < I
LOAD
< 25mA.
Typical case :
V
IN
= 4V, T = 25°C, I
OUT
= 12.5mA.
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.
Parameter Symbol Test Condition Min Typ Max Unit
Input Voltage Range (Note 1) V
IN
35,5V
Output Voltage V
OUT
Adj = 0 1,8 V
Adj = 1 3
Output Voltage Accuracy 3 %
Output current I
OUT
Active mode 0,1 25 mA
Sleep mode 5 500 µA
P
MOS
Output Resistance R
ON
0,6 Ω
Dropout Voltage ∆V
DO
∆V
OUT
= 50mV,
I
LOAD
= 25mA
60 mV
(Note 2) 170
Quiescent current I
Q
I
LOAD
= 100µA, 30 40 µA
I
LOAD
= 25mA 60 80 µA
Stand-by mode current I
QSTDBY
I
LOAD
= 500µA
V
OUT
= 3V
20 30 µA
Power down mode quiescent current I
QPRWDWN
Power down active 100 1 000 nA
Power Supply Rejection Ratio PSRR f < 10KHz 40 50 dB
Load Regulation Ldr 15 25 mV
Line Regulation Lir I
LOAD
= 25mA 5 10 mV
Line Transient Lirt ∆V
IN
= 300mV
t
RISE
= t
FALL
= 10µs
1mV
Load Transient Ldtr 10% to 90%
and 90% to 10%
of 25mA in 10µs
1mV
Output decoupling capacitor C
OUT
1 µF
Settling time
(from power down to active mode)
t
RISE
From power down
to active mode
30 70 µs
t
FALL
From active mode
to power down
60 200 µs
Short Circuit Current Limit I
SHORT
100 200 250 mA
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