lt1776 Linear Technology Corporation, lt1776 Datasheet - Page 3

• Manufacturer Part Number: lt1776
• Description: Wide Input Range, High Efficiency, Step-down Switching Regulator
• Manufacturer: Linear Technology Corporation

ELECTRICAL CHARACTERISTICS
SYMBOL
Timing
f
t
Boost Operation
Sync Function
SHDN Pin Function
V
I
The
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: Control circuitry powered from V
Note 3: Switch current limit is DC trimmed and tested in production.
Inductor dl/dt rate will cause a somewhat higher current limit in actual
application.
Note 4: Minimum switch on time is production tested with a 39 resistive
load to ground.
V
ON(MIN)
SHDN
SHDN
IN
= 40V, V
denotes specifications which apply over the full operating temperature range, otherwise specifications are T
PARAMETER
Switching Frequency
Maximum Switch Duty Cycle
Minimum Switch On Time
V
dV/dt Below Threshold
dV/dt Above Threshold
Minimum Sync Amplitude
Synchronization Range
SYNC Pin Input R
Shutdown Mode Threshold
Upper Lockout Threshold
Lower Lockout Threshold
Shutdown Pin Current
SW
C
Pin Boost Threshold
open, V
CC
= 5V, V
C
= 1.4V unless otherwise noted.
CC
.
CONDITIONS
High dV/dt Mode, R
(Note 6)
Switching Action On
Switching Action Off
V
V
SHDN
SHDN
= 0V
= 1.25V
Note 5: Parts are guaranteed to survive 60V on V
thermal constraints will limit V
on maximum output current and switching frequency. See Applications
section for more information.
Note 6: Internal oscillator is guaranteed to sync up to 400kHz. However,
thermal constraints and/or controllability issues may place a lower limit on
switching frequency in actual usage. See Applications section for more
information.
L
= 39 (Note 4)
IN
in some applications, depending primarily
MIN
180
170
250
0.2
85
1.260
1.245
1.35
TYP
200
300
0.2
1.6
1.5
0.5
2.5
90
40
12
IN
and V
A
= 25 C.
SW
MAX
LT1776
220
230
400
2.2
0.8
20
10
. However,
UNITS
3
V/ns
V/ns
kHz
kHz
kHz
k
ns
%
V
V
V
V
V
V
A
A