Datasheet

LT1074/LT1076
4
sn1074 1074fds
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: To calculate maximum switch “on” voltage at currents between
low and high conditions, a linear interpolation may be used.
Note 3: A feedback pin voltage (V
FB
) of 2.5V forces the V
C
pin to its low
clamp level and the switch duty cycle to zero. This approximates the zero
load condition where duty cycle approaches zero.
Note 4: Total voltage from V
IN
pin to ground pin must be ≥ 8V after start-
up for proper regulation.
Note 5: Switch frequency is internally scaled down when the feedback pin
voltage is less than 1.3V to avoid extremely short switch on times. During
testing, V
FB
is adjusted to give a minimum switch on time of 1µs.
Note 6: I
LIM
≈ (LT1074), I
LIM
≈ (LT1076).
Note 7: Switch to input voltage limitation must also be observed.
Note 8: V
MAX
= 40V for the LT1074/76 and 60V for the LT1074HV/76HV.
Note 9: Does not include switch leakage.
R
LIM
– 1k
2k
R
LIM
– 1k
5.5k
ELECTRICAL CHARACTERISTICS
6V
REGULATOR
AND BIAS
+
–
-POWER
SHUTDOWN
µ
10 Aµ
320 Aµ
+
–
2.35V
0.3V
CURRENT
LIMIT
SHUTDOWN
4.5V
10k
S
+
–
CURRENT
LIMIT
COMP
C2
15
400
+
–
C1
R/S
LATCH
R
R
Q
X
Y
Z
+
–
A1
ERROR
AMP
FB V
100kHz
OSCILLATOR
ANALOG
MULTIPLIER
XY
Z
FREQ SHIFT
SYNC
G1
PULSE WIDTH
COMPARATOR
24V (EQUIVALENT)
2.21V
SWITCH
OUTPUT
(V )
0.04
250
500
INPUT SUPPLY
SHUTDOWN*
I *
6V TO ALL
CIRCUITRY
LIM
Ω
Ω
SW
Ω
Ω
V
IN
C
LT1074 • BD01
100
SWITCH
OUTPUT (V )
0.1
Ω
SW
Ω
3V(p-p)
LT1076
LT1074
*AVAILABLE ON PACKAGES WITH PIN
COUNTS GREATER THAN 5.
BLOCK DIAGRA
W