Datasheet

2
LT1959
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C, T
J
= 25°C, V
IN
= 5V, V
C
= 1.5V, Boost = V
IN
+ 5V, switch open, unless
otherwise noted.
ABSOLUTE MAXIMUM RATINGS
W
WW
U
Input Voltage .......................................................... 16V
BOOST Voltage ........................................................ 30V
BOOST Pin Above Input Voltage ............................. 15V
SHDN Pin Voltage..................................................... 7V
FB Pin Voltage ....................................................... 3.5V
FB Pin Current ....................................................... 1mA
SYNC Pin Voltage ..................................................... 7V
Operating Junction Temperature Range
LT1959C................................................ 0°C to 125°C
LT1959I ........................................... –40°C to 125°C
Storage Temperature Range ................ –65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
ELECTRICAL CHARACTERISTICS
PARAMETER CONDITIONS MIN TYP MAX UNITS
Feedback Voltage (Adjustable) All Conditions ● 1.19 1.21 1.23 V
Reference Voltage Line Regulation 4.3V ≤ V
IN
≤ 15V 0.01 0.03 %/V
Feedback Input Bias Current ● –0.5 0 0.5 µA
Error Amplifier Voltage Gain (Note 2) 200 400
Error Amplifier Transconductance ∆I (V
C
) = ±10µA 1500 2000 2700 µMho
● 1000 3100 µMho
V
C
Pin to Switch Current Transconductance 5.3 A/V
Error Amplifier Source Current V
FB
= 1.05V ● 140 225 320 µA
Error Amplifier Sink Current V
FB
= 1.35V ● 140 225 320 µA
V
C
Pin Switching Threshold Duty Cycle = 0 0.9 V
V
C
Pin High Clamp 2.1 V
Switch Current Limit V
C
Open, V
FB
= 1.05V, DC ≤ 50% ● 4.5 6 8.5 A
Slope Compensation DC = 80% 0.8 A
PACKAGE/ORDER INFORMATION
W
U
U
ORDER PART
NUMBER
ORDER PART
NUMBER
LT1959CR
LT1959IR
1959
1959I
S8 PART MARKING
LT1959CS8
LT1959IS8
(Note 1)
1
2
3
4
8
7
6
5
TOP VIEW
S8 PACKAGE
8-LEAD PLASTIC SO
V
IN
BOOST
GND**
V
SW
SYNC
SHDN
V
C
FB
R PACKAGE
7-LEAD PLASTIC DD
FRONT VIEW
FB
BOOST
V
IN
GND
V
SW
7
6
5
4
3
2
1
SHDN
V
C
TAB
IS
GND
**WITH (FUSED GND) GROUND PIN
CONNECTED TO GROUND PLANE OR
LARGE LANDS
T
JMAX
= 150°C, θ
JA
= 30°C/W
WITH PACKAGE SOLDERED TO 0.5 SQUARE INCH
COPPER AREA OVER BACKSIDE GROUND PLANE OR
INTERNAL POWER PLANE. θ
JA
CAN VARY FROM 20°C/W
TO >40°C/W DEPENDING ON MOUNTING TECHNIQUES
T
JMAX
= 150°C, θ
JA
= 80°C/W