LTC3523-2_15 Datasheet, PDF (4/16 Pages) Linear Technology – Synchronous 600mA Step-Up and 400mA Step-Down DC/DC Converters

LTC3523/LTC3523-2
TYPICAL PERFORMANCE CHARACTERISTICS (T_A = 25°C unless otherwise noted)
Normalized FBx Reference vs
Temperature
1.00125
1.00000
0.99875
0.99750
0.99625
0.99500
–45 –25
–5 15 35 55
TEMPERATURE (°C)
75
3523 G01
Inrush Current Control for the
Step-Down Converter
V_{OUT_BCK}
1V/DIV
I_{L_BCK}
200mA/DIV
SHDN2
2V/DIV
V_OUT = 1.2V
V_IN = 2.4V
C_OUT = 10μF
L1 = 4.7μH
200μs/DIV
3523 G04
Normalized Oscillator Frequency
vs Temperature
1.05
1.00
Inrush Current Control for the
Step-Up Converter
V_{OUT_BST}
2V/DIV
I_{L_BST}
200mA/DIV
SHDN1
2V/DIV
V_OUT = 3.3V
V_IN = 2.4V
C_OUT = 10μF
L1 = 4.7μH
200μs/DIV
3523 G03
0.95
–45 –25
–5 15 35 55
TEMPERATURE (°C)
75
3523 G02
Load Transient Response Step-Up
OUTPUT
RIPPLE
20mV/DIV
LOAD
CURRENT
20mA/DIV
Load Transient Response
Step-Down
OUTPUT
RIPPLE
20mV/DIV
LOAD
CURRENT
20mA/DIV
V_OUT = 3.3V
V_IN = 2.4V
C_OUT = 10μF
L1 = 4.7μH
500μs/DIV
20mA TO 70mA STEP
3523 G05
V_OUT = 1.2V
V_IN = 2.4V
C_OUT = 47μF
L1 = 4.7μH
500μs/DIV
C_F = 68pF
10mA TO 30mA STEP
3523 G06
Current Limit vs Temperature
1.2
BOOST CURRENT
LIMIT
1.0
0.8
BUCK CURRENT
0.6
LIMIT
0.4
0.2
0
–45 –25
–5 15 35 55
TEMPERATURE (°C)
75
3523 G07
R_DS(ON) vs Input Voltage for the
Step-Down Converter
0.80
0.70
0.60
PMOS
0.50
0.40
0.30
NMOS
0.20
0.10
0
1 1.5 2 2.5 3 3.5 4 4.5 5
INPUT VOLTAGE (V)
3523 G08
R_DS(ON) vs Output Voltage for the
Step-Up Converter
0.50
0.45
0.40
PMOS
0.35
0.30
0.25
NMOS
0.20
0.15
0.10
0.05
0
1 1.5 2 2.5 3 3.5 4 4.5 5
OUTPUT VOLTAGE (V)
3532 G09
3523fb
4