Datasheet

2
LT1576/LT1576-5
ABSOLUTE MAXIMUM RATINGS
W
WW
U
PACKAGE/ORDER INFORMATION
W
U
U
(Note 1)
Input Voltage .......................................................... 25V
BOOST Pin Above Input Voltage ............................. 10V
SHDN Pin Voltage.................................................. 6.5V
BIAS Pin Voltage ...................................................... 7V
FB Pin Voltage (Adjustable Part)............................ 3.5V
FB Pin Current (Adjustable Part)............................ 1mA
SYNC Pin Voltage ..................................................... 7V
Operating Junction Temperature Range
LT1576C............................................... 0°C to 125° C
LT1576I ........................................... –40°C to 125°C
Storage Temperature Range ................ –65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
ORDER PART NUMBER
LT1576CS8
LT1576CS8-SYNC
LT1576IS8
LT1576IS8-SYNC
LT1576CS8-5
LT1576CS8-5 SYNC
LT1576IS8-5
LT1576IS8-5 SYNC
S8 PART MARKING
1576
1576SN
1576I
576ISN
*Default is the adjustable output voltage device with FB pin and shutdown
function. Option -5 replaces FB with SENSE pin for fixed 5V output
applications. -SYNC replaces SHDN with SYNC pin for applications
requiring synchronization. Consult factory for Military grade parts.
1
2
3
4
8
7
6
5
TOP VIEW
S8 PACKAGE
8-LEAD PLASTIC SO
V
SW
V
IN
BOOST
GND
FB OR SENSE*
V
C
BIAS
SHDN OR
SYNC*
θ
JA
=80°C/W WITH FUSED GROUND PIN
CONNECTED TO GROUND PLANE OR
LARGE LANDS
PARAMETER CONDITIONS MIN TYP MAX UNITS
Feedback Voltage 1.195 1.21 1.225 V
5V ≤ V
IN
≤ 25V, V
OL
+ 0.2V ≤ V
CC
≤ V
OH
– 0.2V ● 1.18 1.24 V
Sense Voltage (Fixed 5V) 4.94 5.0 5.06 V
All Conditions
● 4.90 5.10 V
SENSE Pin Resistance 13 18.5 26 kΩ
Reference Voltage Line Regulation 5V ≤ V
IN
≤ 25V 0.01 0.03 %/V
Feedback Input Bias Current ● 0.5 2 µA
Error Amplifier Voltage Gain (Notes 2, 8) 200 400
Error Amplifier Transconductance ∆I (V
C
) = ±10µA (Note 8) 800 1050 1300 µMho
● 400 1700 µMho
V
C
Pin to Switch Current Transconductance 1.5 A/V
Error Amplifier Source Current V
FB
= 1V ● 40 110 190 µA
Error Amplifier Sink Current V
FB
= 1.4V ● 50 130 200 µA
V
C
Pin Switching Threshold Duty Cycle = 0 0.8 V
V
C
Pin High Clamp 2.1 V
Switch Current Limit V
C
Open, V
FB
= 1.1V, DC ≤ 50% ● 1.5 2 3.50 A
Slope Compensation (Note 9) DC = 80% 0.3 A
Switch On Resistance (Note 7) I
SW
= 1.5A 0.2 0.35 Ω
● 0.45 Ω
Maximum Switch Duty Cycle V
FB
= 1.1V 90 94 %
● 86 94 %
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating temperature
range, otherwise specifications are T
A
, T
J
= 25°C, V
IN
= 15V, V
C
= 1.5V, Boost = V
IN
+ 5V, switch open, unless otherwise noted.
15765
5765SN
1576I5
76I5SN