Datasheet

2
LT1738
1738fa
(Note 1)
Supply Voltage (V
IN
)................................................ 20V
Gate Drive Current .....................................Internal Limit
V5 Current .................................................Internal Limit
SHDN Pin Voltage.................................................... 20V
Feedback Pin Voltage (Trans. 10ms) ...................... ±10V
Feedback Pin Current............................................ 10mA
Negative Feedback Pin Voltage (Trans. 10ms)........ ±10V
CS Pin.......................................................................... 5V
GCL Pin ..................................................................... 16V
SS Pin.......................................................................... 3V
Operating Junction Temperature Range
(Note 3) ............................................ –40°C to 125°C
Storage Temperature Range ................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)..................300°C
ORDER PART
NUMBER
LT1738EG
LT1738IG
T
JMAX
= 150°C, θ
JA
= 110°C/W
ELECTRICAL CHARACTERISTICS
ABSOLUTE AXI U RATI GS
W
WW
U
PACKAGE/ORDER I FOR ATIO
UUW
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 12V, V
C
= 0.9V, V
FB
= V
REF
, R
VSL
, R
CSL
= 16.9k, R
T
= 16.9k and
other pins open unless otherwise noted.
1
2
3
4
5
6
7
8
9
10
TOP VIEW
G PACKAGE
20-LEAD PLASTIC SSOP
20
19
18
17
16
15
14
13
12
11
GATE
CAP
GCL
CS
V5
SYNC
C
T
R
T
FB
NFB
PGND
NC
NC
V
IN
R
VSL
R
CSL
SHDN
SS
V
C
GND
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Error Amplifiers
V
REF
Reference Voltage Measured at Feedback Pin ● 1.235 1.250 1.265 V
I
FB
Feedback Input Current V
FB
= V
REF
● 250 1000 nA
FB
REG
Reference Voltage Line Regulation 2.7V ≤ V
IN
≤ 20V ● 0.012 0.03 %/V
V
NFR
Negative Feedback Reference Voltage Measured at Negative Feedback Pin ● –2.56 –2.50 –2.45 V
with Feedback Pin Open
I
NFR
Negative Feedback Input Current V
NFB
= V
NFR
–37 –25 µA
NFB
REG
Negative Feedback Reference Voltage Line Regulation 2.7V ≤ V
IN
≤ 20V ● 0.009 0.03 %/V
g
m
Error Amplifier Transconductance ∆I
C
= ±50µA 1100 1500 2200 µmho
● 700 2500 µmho
I
ESK
Error Amp Sink Current V
FB
= V
REF
+ 150mV, V
C
= 0.9V ● 120 200 350 µA
I
ESRC
Error Amp Source Current V
FB
= V
REF
– 150mV, V
C
= 0.9V ● 120 200 350 µA
V
CLH
Error Amp Clamp Voltage High Clamp, V
FB
= 1V 1.27 V
V
CLL
Error Amp Clamp Voltage Low Clamp, V
FB
= 1.5V 0.12 V
A
V
Error Amplifier Voltage Gain 180 250 V/V
FB
OV
FB Overvoltage Shutdown Outputs Drivers Disabled 1.47 V
I
SS
Soft-Start Charge Current V
SS
= 1V 9.0 12 µA
Consult LTC Marketing for parts specified with wider operating temperature ranges.