Datasheet
LT1946
2
1946fb
PACKAGE/ORDER I FOR ATIO
UUW
T
JMAX
= 125°C, θ
JA
= 40°C/W,
θ
JC
= 10°C/W
ORDER PART
NUMBER
MS8 PART MARKING
T
JMAX
= 125°C, θ
JA
= 125°C/W
(4-LAYER BOARD)
LTUG
LT1946EMS8
1
2
3
4
V
C
FB
SHDN
GND
8
7
6
5
SS
COMP
V
IN
SW
TOP VIEW
MS8 PACKAGE
8-LEAD PLASTIC MSOP
ORDER PART
NUMBER
MS8 PART MARKING
LTBNW
LT1946EMS8E
1
2
3
4
8
7
6
5
TOP VIEW
MS8E PACKAGE
8-LEAD PLASTIC MSOP
EXPOSED PAD (PIN 9) IS GROUND
(MUST BE SOLDERED TO PCB)
V
C
FB
SHDN
GND
SS
COMP
V
IN
SW
9
V
IN
Voltage ............................................................. 16V
SW Voltage ............................................... –0.4V to 36V
FB Voltage ............................................................. 2.5V
SHDN Voltage ......................................................... 16V
Current Into FB Pin .............................................. ±1mA
(Note 1)
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 specified. (Note 2)
SYMBOL CONDITIONS MIN TYP MAX UNITS
Minimum Operating Voltage 2.45 2.6 V
Maximum Operating Voltage 16 V
Feedback Voltage 1.230 1.250 1.270 V
● 1.220 1.270 V
FB Pin Bias Current V
FB
= 1.250V (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 3.2 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 0.9 1.2 1.4 MHz
● 0.8 1.5 MHz
Switching Frequency in Foldback V
FB
= 0V 0.4 MHz
Maximum Duty Cycle ● 86 90 %
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
ABSOLUTE AXI U RATI GS
WWWU
ELECTRICAL CHARACTERISTICS
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
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Order Options Tape and Reel: Add #TR Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: http://www.linear.com/leadfree/