LT1942
2
1942fb
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/
V
CC
Voltage............................................................. 16V
SW1, SW2, SW3 Voltage .......................... –0.4V to 36V
SW4.......................................................... –0.4V to 45V
FB1, FB3 Voltage ................................................... 2.5V
FB4 Voltage ....................................................... 400mV
NFB2 Voltage ................................................... –200mV
SHDN Voltage ......................................................... 10V
CTRL4 Voltage ........................................................ 16V
SS1, SS4 Voltage .................................................. 1.5V
Current Into D2 ......................................................... 1A
D2 Voltage ............................................................ –36V
Current Out of D3 ..................................................... 1A
D3 Voltage .............................................................. 36V
Current Out of D4 ..................................................... 4A
D4 Voltage .............................................................. 45V
LED1, LED2 Voltage ............................................... 45V
Current Into LED1, LED2 ..................................... 35mA
PGOOD Voltage ...................................................... 16V
V
OUT3
Voltage ......................................................... 36V
CT Current ........................................................... ±1mA
Maximum Junction Temperature ......................... 125°C
Operating Temperature Range (Note 2) .. – 40°C to 85°C
Storage Temperature Range ................ –65°C to 125°C
ORDER PART
NUMBER
(Note 1)
ABSOLUTE AXI U RATI GS
WWWU
PACKAGE/ORDER I FOR ATIO
UU
W
Consult LTC Marketing for parts specified with wider operating temperature ranges.
LT1942EUF
T
JMAX
= 125°C, θ
JA
= 37°C/W, θ
JC
= 4.3°C/W
EXPOSED PAD (PIN 25) IS SGND
(MUST BE SOLDERED TO PCB)
The
● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 3.3V, V
SHDN
= V
IN
, unless otherwise noted. (Note 2)
PARAMETER CONDITIONS MIN TYP MAX UNITS
Quiescent Current V
SHDN
= 3.3V, V
CTRL4
= 0V, Not Switching ● 710 mA
V
SHDN
= V
CTRL4
= 0V, In Shutdown ● 01 µA
Input Voltage Range V
CC
Pin ● 2.6 16 V
AV
DD
Feedback Voltage FB1 Pin ● 1.225 1.25 1.275 V
AV
DD
Feedback Pin Bias Current (FB1) FB1 Pin (Note 3) 15 60 nA
AV
DD
Feedback Voltage for Power Good Signal FB1 Pin Voltage as a Percent of Nominal Voltage ● 95 97 100 %
V
OFF
Feedback Voltage NFB2 Pin –160 –150 –140 mV
V
OFF
Feedback Pin Bias Current (NFB2) NFB2 Pin (Note 3) 25 60 nA
V
ON
Feedback Voltage FB3 Pin 1.225 1.25 1.275 V
V
ON
Feedback Pin Bias Current (FB3) FB3 Pin (Note 3) 25 60 nA
LED Feedback Voltage FB4 Pin, V
CTRL4
= 3.3V ● 190 200 210 mV
LED Feedback Pin Bias Current (FB4) FB4 Pin (Note 3) 20 60 µA
LED Feedback Voltage with Dimming FB4 Pin, V
CTRL4
= 1V 85 95 105 mV
ELECTRICAL CHARACTERISTICS
24 23 22 21 20 19
7 8 9
TOP VIEW
25
UF PACKAGE
24-LEAD (4mm × 4mm) PLASTIC QFN
10 11 12
6
5
4
3
2
1
13
14
15
16
17
18
PGND23
SW3
D3
V
OUT3
FB3
NFB2
LED1
LED2
D4
FB4
FB1
PGOOD
SW2
D2
V
CC
PGND14
SW1
SW4
SHDN
CTRL4
CT
AGND
SS1
SS4
UF PART
MARKING
1942