LTC3025-4 Linear Technology, LTC3025-4 Datasheet - Page 10

• Manufacturer Part Number: LTC3025-4
• Description: 500mA Micropower VLDO Linear Regulators
• Manufacturer: Linear Technology

TYPICAL APPLICATION
LTC3025-1/LTC3025-2/
LTC3025-3/LTC3025-4
APPLICATIONS INFORMATION
shutdown without latch-up or damage until the overstress
condition is removed. Long term overstress (T
should be avoided as it can degrade the performance or
shorten the life of the part.
Soft-Start Operation
The LTC3025-X includes a soft-start feature to prevent
excessive current fl ow during start-up. When the LDO is
enabled, the soft-start circuitry gradually increases the LDO
reference voltage from 0V to 0.4V over a period of about
600μs. There is a short 700μs delay from the time the
part is enabled until the LDO output starts to rise. Figure
5 shows the start-up and shutdown output waveform.
10
TO 5.5V
2.7V
V
OFF ON
IN
C
4.7μF
CER
IN
**
**
*
High Effi ciency 1.5V Step-Down Converter with Effi cient 1.2V VLDO Output
†
MURATA LQH32CN2R2M33
TAIYO YUDEN JMK212BJ475MG
TAIYO YUDEN JMK316BJ106ML
4
1
V
RUN
LTC3406-1.5
IN
GND
V
OUT
SW
100
3
5
90
80
70
60
50
40
0.1
2.2μH*
600mA
V
1.5V
V
OUT
J
IN
Effi ciency vs Output Current
> 125°C)
= 3.6V
1
OUTPUT CURRENT (mA)
C
10μF
CER
OUT
LTC3406-1.5
V
V
0.1μF
LTC3025-1
OUT
OUT
†
= 1.5V
= 1.2V
10
1
3
6
200mV/DIV
BIAS
IN
SHDN
SHDN
V
LTC3025-1
OUT
100
1.2V
30251234 TA03
OFF
ON
0V
Figure 5. Output Start-Up and Shutdown
GND
OUT
T
V
V
C
R
ADJ
1000
A
IN
BIAS
OUT
LOAD
= 25°C
= 1.5V
= 1μF
= 3.6V
4
5
2
= 4Ω
80.6k
40.2k
30251234 TA02
500μs/DIV
1μF
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V
I
OUT
OUT
≤ 500mA
= 1.2V
30251234 F05
30251234fc