Datasheet

LT1946A
2
sn1946a 1946afs
V
IN
Voltage .............................................................. 16V
SW Voltage ................................................–0.4V to 36V
FB Voltage .............................................................. 2.5V
Current into FB Pin ............................................... ±1mA
SHDN Voltage .......................................................... 16V
Maximum Junction Temperature .......................... 125°C
Operating Temperature
Range (Note 2) ....................................... –40°C to 85°C
Storage Temperature Range ................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)..................300°C
ORDER PART
NUMBER
MS8E PART
MARKING
T
JMAX
= 125°C, θ
JA
= 40°C/W,
θ
JC
= 10°C/W
Consult LTC Marketing for parts specified with wider operating temperature ranges.
LTYZ
LT1946AEMS8E
(Note 1)
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: The LT1946AE is guaranteed to meet performance specifications
from 0°C to 70°C. Specifications over the –40°C to 85°C operating
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 3V, V
SHDN
= V
IN
unless otherwise noted. (Note 2)
PARAMETER CONDITIONS MIN TYP MAX UNITS
Minimum Operating Voltage 2.45 2.6 V
Maximum Operating Voltage 16 V
Feedback Voltage 1.23 1.25 1.27 V
● 1.22 1.27 V
FB Pin Bias Current V
FB
= 1.25V (Note 3) ● 20 120 nA
Error Amp Transconductance ∆I = 2µA40µmhos
Error Amp Voltage Gain 300 V/V
Quiescent Current V
SHDN
= 2.5V, Not Switching 3.6 5 mA
Quiescent Current in Shutdown V
SHDN
= 0V, V
IN
= 3V 0 1 µA
Reference Line Regulation 2.6V ≤ V
IN
≤ 16V 0.01 0.05 %/V
Switching Frequency 2.4 2.7 3 MHz
● 2.3 3.1 MHz
Switching Frequency in Foldback V
FB
= 0V 0.85 MHz
Maximum Duty Cycle ● 73 80 %
Switch Current Limit (Note 4) ● 1.5 2.1 3.1 A
Switch V
CESAT
I
SW
= 1A 240 340 mV
Switch Leakage Current V
SW
= 5V 0.01 1 µA
Soft-Start Charging Current V
SS
= 0.5V 2.5 4 6 µA
SHDN Input Voltage High 2.4 V
SHDN Input Voltage Low 0.5 V
SHDN Pin Bias Current V
SHDN
= 3V 16 32 µA
V
SHDN
= 0V 0 0.1 µA
temperature range are assured by design, characterization and correlation
with statistical process controls.
Note 3: Current flows out of the FB pin.
Note 4: Current limit guaranteed by design and/or correlation to static test.
Current limit is independent of duty cycle and is guaranteed by design.
1
2
3
4
V
C
FB
SHDN
GND
8
7
6
5
SS
COMP
V
IN
SW
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(MUST BE SOLDERED TO PCB)
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