Datasheet

7
LTC1421/LTC1421-2.5
BLOCK DIAGRAM
W
Figure 1. Nominal Operation Switching Waveforms
Figure 2. Fault Detection Switching
CPON
CON1
t
1
CON2
RESET
DISABLE
POR
1421 F01
PWRGD
t
2
t
3
t
4
t
6
t
5
t
7
CPON
V
CCLO
– SETLO
t
9
FAULT
RESET
POR
1421 F02
PWRGD
t
2
t
5
t
11
t
6
t
10
SWITCHI G TI E WAVEFOR S
UW W
–
+
+
–
+
+
–
V
TRIP
+
–
+
–
50mV50mV
CPON
AUXV
CC
V
CCHI
SETLO
CP1 CP2
V
CCLO
SETHI GATELO RAMP GATEHI V
OUTHI
V
OUTLO
192223 18 21 10 17 16 20
V
CC
FAULT
CON1
CON2
POR
DISABLE
9
24
4
1
2
3
5
20µA
V
CC
CP3
CP4
CP5
73.5k
N1N2
AUXV
CC
FB
REF
11
8
PWRGD
6
RESET
7
COMPOUT
15
COMP
–
14
COMP
+
13
1421 BD
71.5k
26.7k
20µA
20µA
1.232V
REFERENCE
CHARGE
PUMP
UNDERVOLTAGE
LOCKOUT
RESET
TIMING
V
CC
V
CC
V
CC
–
+
GND
DIGITAL CONTROL
12