Datasheet
2
LT1956/LT1956-5
1956f
Input Voltage (V
IN
) ................................................. 60V
BOOST Pin Above SW ............................................ 35V
BOOST Pin Voltage ................................................. 68V
SYNC, SENSE Voltage (LT1956-5) ........................... 7V
SHDN Voltage ........................................................... 6V
BIAS Pin Voltage .................................................... 30V
FB Pin Voltage/Current (LT1956)................... 3.5V/2mA
ORDER PART
NUMBER
LT1956EGN
LT1956IGN
LT1956EGN-5
LT1956IGN-5
GN PART MARKING
1956
1956I
19565
1956I5
T
JMAX
= 125°C, θ
JA
= 85°C/W, θ
JC
(PIN 8) = 25°C/W
FOUR CORNER PINS SOLDERED
TO GROUND PLANE
ABSOLUTE AXI U RATI GS
WWWU
PACKAGE/ORDER I FOR ATIO
UU
W
GN PACKAGE
16-LEAD PLASTIC SSOP
1
2
3
4
5
6
7
8
TOP VIEW
16
15
14
13
12
11
10
9
GND
SW
NC
V
IN
NC
BOOST
NC
GND
GND
SHDN
SYNC
NC
FB/SENSE
V
C
BIAS
GND
Operating Junction Temperature Range
LT1956EFE/LT1956EFE-5/LT1956EGN/LT1956EGN-5
(Notes 8, 10) ..................................... –40°C to 125°C
LT1956IFE/LT1956IFE-5/LT1956IGN/LT1956IGN-5
(Notes 8, 10) ..................................... –40°C to 125°C
Storage Temperature Range ................ –65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
(Note 1)
ORDER PART
NUMBER
LT1956EFE
LT1956IFE
LT1956EFE-5
LT1956IFE-5
FE PART MARKING
T
JMAX
= 125°C, θ
JA
= 45°C/W, θ
JC
(PAD) = 10°C/W
EXPOSED BACKSIDE MUST BE SOLDERED
TO GROUND PLANE
FE PACKAGE
16-LEAD PLASTIC TSSOP
1
2
3
4
5
6
7
8
TOP VIEW
16
15
14
13
12
11
10
9
GND
SW
NC
V
IN
NC
BOOST
NC
GND
GND
SHDN
SYNC
NC
FB/SENSE
V
C
BIAS
GND
Consult LTC Marketing for parts specified with wider operating temperature ranges.
PARAMETER CONDITIONS MIN TYP MAX UNITS
Reference Voltage (LT1956) 5.5V ≤ V
IN
≤ 60V 1.204 1.219 1.234 V
V
OL
+ 0.2 ≤ V
C
≤ V
OH
– 0.2 ● 1.195 1.243 V
SENSE Voltage (LT1956-5) 5.5V ≤ V
IN
≤ 60V 4.94 5 5.06 V
V
OL
+ 0.2 ≤ V
C
≤ V
OH
– 0.2 ● 4.90 5.10 V
SENSE Pin Resistance (LT1956-5) 9.5 13.8 19 kΩ
FB Input Bias Current (LT1956) ● 0.5 1.5 µA
Error Amp Voltage Gain (Notes 2, 9) 200 400 V/V
Error Amp g
m
dl (V
C
) = ±10µA (Note 9) 1500 2000 3000 µMho
● 1000 3200 µMho
V
C
to Switch g
m
1.7 A/V
EA Source Current FB = 1V or V
SENSE
= 4.1V ● 125 225 400 µA
EA Sink Current FB = 1.4V or V
SENSE
= 5.7V ● 100 225 450 µA
V
C
Switching Threshold Duty Cycle = 0 0.9 V
V
C
High Clamp SHDN = 1V 2.1 V
The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at T
J
= 25°C.
V
IN
= 15V, V
C
= 1.5V, SHDN = 1V, Boost o/c, SW o/c, unless otherwise noted.
ELECTRICAL CHARACTERISTICS
1956EFE
1956IFE
1956EFE-5
1956IFE-5