Datasheet
10
LTC1923
1923f
FU CTIO AL DIAGRA
U
U
W
–
+
–
+
–
+
–
+
–
+
–
+
–
–
–
+
TSD
1.5V
SS
ENABLE
ENABLE
S
R
Q
S
Q
1/2 V
DD
1 = NO SLEW LIMITING
SWITCHES OPEN
QB
R
Q
Q
350mV
OPEN/SHORTED THERMISTOR
0.2V
SET
V
SET
CNTRL
–
+
SDSYNC
PLLLPF
R
SLEW
SLEW LIMITING
V
DD
I
SLEW
0.7V
1 = SHDN
V
DD
+ V
BE
EAOUT
FB
C
T
RAMP = 0.5V – 1.5V
R
T
0.5V
I
RT
R
V
THRM
DIGITAL
PHASE
DETECTOR
SHUTDOWN
COMPARATOR
MASTER
COMPARATOR
OSCILLATOR
ERROR
AMPLIFIER
FAULT I
TEC
V
TEC
H/C
1923 BD
TEC
+
CS
–
CS
+
I
LIM
SS
1.5µA
PGND
NDRVB
V
DD
TEC
–
2.5V LDO
REF
V
REF
AGND
REFGOOD
UVLO
SHDN
TSD
V
BG
V
REF
GOOD
COMPARATOR
1 = REFGOOD
ENABLE
UVLO
1 = UVLO
V
DD
20µs
DELAY
R
2R
Q
ENABLE
OSC VALLEY
CURRENT LIMIT
1V
–
+
INPUT
SELECT
X10
CS AMP
TEC AMP
–
+
–
+
INPUT
SELECT
DIRECTIONAL
COMPARATOR
X1
–
+
–
+
0.3V
V
DD
– 0.4V
–
+
g
m
2.5V
TEC
CLAMP
V
TEC
–
+
g
m
g
m
Q
Q
S
R
QB
ENABLE
OSC PEAK
Q
Q
S
R
NDRVA
PDRVB
PDRVA
V
DD
90ns
DELAY
PDRVA
PDRVB
NDRVA
90ns
DELAY
DELAY
∝
I
RT
NDRVA
1
4