LTC3421_15 Datasheet, PDF (16/16 Pages) Linear Technology – 3A, 3MHz Micropower Synchronous Boost Converter with Output Disconnect

LTC3421
TYPICAL APPLICATIO
Single Cell to 3.3V at 500mA with Secondary Cell Backup During Shutdown. LOWBAT and V_REF Output are Enabled
V_IN
1V TO 1.5V
1 CELL ⁺
PRIMARY CELL
C1*
4.7µF
301k
604k
L1
4.7µH
2 21 14 15 16
0.1µF
4
3
23
LOW BAT ²²
OUTPUT ₇
SHDN
ENB
V_REF
LBI
LBO
SYNC
V_IN SW SW SW
18
V_OUTS
V_OUT ¹⁷
V_OUT ¹⁹
LTC3421
V_OUT ²⁰
1
FB
8 _ILIM
R1
60k _{SS RT}
V_C ²⁴
BURST ⁹
GND PGND PGND PGND
65
10 11 12 13
C2
R2
C3
0.1µF
28k
0.1µF
*LOCATE COMPONENTS CLOSE TO PINS C5: TAIYO YUDEN JMK325BJ226MM
C1: TAIYO YUDEN JMK212BJ106MM
L1: TOKO A916CY-4R7M
D1
+ _3V
SECONDARY CELL
V_OUT
3.3V
500mA
R5
340k
C4
470pF
R3
40k
R6
200k
R4
100k
C5*
22µF
3421 TA05
Single Cell to 3.3V Efficiency
100
Burst Mode OPERATION
90
V_IN = 1.5V
80
V_IN = 1.2V
70
V_IN = 1V
60
50
40
30
20
10 ^VOUT ^{= 3.3V}
f_OSC = 1MHz
0
0.1
1
10
100
OUTPUT CURRENT (mA)
1000
3421 G01
RELATED PARTS
PART NUMBER
LT1371/LT1371HV
LTC3400/LTC3400B
LTC3401
DESCRIPTION
3A (I_SW), 500kHz, High Efficiency Step-Up DC/DC
Converters
600mA (I_SW), 1.2MHz, Synchronous Step-Up DC/DC
Converters
1A (I_SW), 3MHz, Synchronous Step-Up DC/DC Converter
LTC3402
2A (I_SW), 3MHz, Synchronous Step-Up DC/DC Converter
LTC3425
5A (I_SW), 8MHz, 4-Phase Synchronous Step-Up
DC/DC Converter
16 Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone] ^q FAX: [phone] ^q www.linear.com
COMMENTS
V_IN: 2.7V to 30V, V_OUT(MAX): 35V/42V, I_Q: 4mA, I_SD: <12µA,
DD, TO220-7, S20
92% Efficiency, V_IN: 0.85V to 5V, V_OUT(MAX): 5V, I_Q: 19µA/300µA,
I_SD: <1µA, ThinSOT
97% Efficiency, V_IN: 0.5V to 5V, V_OUT(MAX): 5.5V, I_Q: 38µA,
I_SD: <1µA, MS10
97% Efficiency, V_IN: 0.5V to 5V, V_OUT(MAX): 5.5V, I_Q: 38µA,
I_SD: <1µA, MS10
95% Efficiency, V_IN: 0.5V to 4.5V, V_OUT(MAX): 5.25V, I_Q: 12µA,
8MHz, Low Ripple in QFN
3421f
LT/TP 1103 1K PRINTED IN USA
© LINEAR TECHNOLOGY CORPORATION 2003