Datasheet

2
LT1776
ABSOLUTE MAXIMUM RATINGS
W
WW
U
(Note 1)
Supply Voltage (Note 5) .......................................... 60V
Switch Voltage (Note 5)........................................... 60V
SHDN, SYNC Pin Voltage........................................... 7V
V
CC
Pin Voltage ....................................................... 30V
FB Pin Voltage ........................................................... 3V
Operating Junction Temperature Range
LT1776C................................................ 0°C to 125°C
LT1776I ............................................ –40°C to 125°C
Storage Temperature Range ................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)..................300°C
PACKAGE/ORDER INFORMATION
W
U
U
ORDER PART
NUMBER
LT1776CN8
LT1776CS8
LT1776IN8
LT1776IS8
S8 PART MARKING
1776
1776I
Consult factory for Military grade parts.
V
IN
= 40V, V
SW
open, V
CC
= 5V, V
C
= 1.4V unless otherwise noted.
The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are T
A
= 25°C.
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Power Supplies
V
IN(MIN)
Minimum Input Voltage 6.7 7.0 V
● 7.4 V
Thermally Limited Continuous Operating Voltage ● 40 V
I
VIN
V
IN
Supply Current V
C
= 0V 620 800 µA
● 900 µA
I
VCC
V
CC
Supply Current V
C
= 0V 3.2 4.0 mA
● 5.0 mA
V
VCC
V
CC
Dropout Voltage (Note 2) 2.8 3.1 V
Shutdown Mode I
VIN
V
SHDN
= 0V 30 50 µA
● 75 µA
Feedback Amplifier
V
REF
Reference Voltage 1.225 1.240 1.255 V
● 1.215 1.265 V
I
IN
FB Pin Input Bias Current 600 1500 nA
g
m
Feedback Amplifier Transconductance ∆lc = ±10µA 400 650 1000 µmho
● 200 1500 µmho
I
SRC
, I
SNK
Feedback Amplifier Source or Sink Current 60 100 170 µA
● 45 220 µA
V
CL
Feedback Amplifier Clamp Voltage 2.0 V
Reference Voltage Line Regulation 12V ≤ V
IN
≤ 60V ● 0.01 %/V
Voltage Gain 200 600 V/V
Output Switch
V
ON
Output Switch On Voltage I
SW
= 0.5A 1.0 1.5 V
I
LIM
Switch Current Limit (Note 3) ● 0.55 0.70 1.0 A
Current Amplifier
Control Pin Threshold Duty Cycle = 0% 0.9 1.1 1.25 V
Control Voltage to Switch Transconductance 2 A/V
T
JMAX
= 125°C, θ
JA
= 130°C/ W (N8)
T
JMAX
= 125°C, θ
JA
= 110°C/ W (S8)
1
2
3
4
8
7
6
5
TOP VIEW
V
C
FB
SYNC
V
IN
SHDN
V
CC
V
SW
GND
N8 PACKAGE
8-LEAD PDIP
S8 PACKAGE
8-LEAD PLASTIC SO
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