900,000+ datasheet pdf search and download

Datasheet4U offers most rated semiconductors data sheet pdf




Linear Technology Electronic Components Datasheet

LT1942 Datasheet

Quad DC/DC Converter

No Preview Available !

FEATURES
Triple Output TFT Supply with Built-In
Power Sequencing
Integrated White LED Backlight Driver
Integrated Schottky Diodes
Active Ballast Circuitry Ensures Precise Current
Matching in White LEDs
Low Noise 1MHz Fixed Frequency Operation
2.6V to 16V Input Voltage Range
Soft-Start Limits Inrush Current
TFT Supply Output Voltages Independently Set
(Not Charge Pump Derived)
Power Good and Output Disconnect for TFT Supply
Built-In LED Dimming Capability
Open LED Protection for LED Driver
24-Lead QFN Package (4mm × 4mm)
U
APPLICATIO S
Poly-Silicon TFT Displays
Amorphous Silicon TFT Displays
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
LT1942
Quad DC/DC Converter
for Triple Output TFT Supply
Plus LED Driver
DESCRIPTIO
The LT®1942 is a highly integrated quad switching regu-
lator designed to provide all necessary power supply
functions for TFT displays, including the white LED
backlight driver. The TFT supply incorporates two boost
and one inverting DC/DC converters. The TFT supply
output voltages are independently set, unlike charge
pump solutions which have many limitations. Power
sequencing for the TFT supply is built into the part and is
user programmable.
The LED driver is a boost DC/DC converter that can be
independently controlled. The LED driver has built-in
dimming control for precise control of LED current. An 8:1
dimming range is achieved by adjusting the CTRL4 volt-
age. The user can elect to drive a single string or two
strings of LEDs. An LED ballast circuit is included to
precisely match the LED currents if two strings of LEDs are
used. Soft-start is built into the LED driver as well as the
primary TFT supply.
The LT1942 is available in a low profile (0.75mm) 24-lead
QFN (4mm × 4mm) package.
TYPICAL APPLICATIO
TFT Bias and White LED Backlight Power Supply
VIN
3V TO 4.2V
2.2µF
VON 0.22µF
10V
2mA
10k
0.22µF
VOFF
–10V
2mA
665k
VIN
SHUTDOWN
LED CONTROL
47µH
47µH
22µH CMDSH-3
22µH
301k 4.7pF
698k D3 SW3 VCC SW1
FB3 FB1 100k 4.7µF
100k PGND14
PGND23
PGOOD
VOUT3
NFB2
LT1942
SW4
33µH
D4
VIN
D2
0.1µF
SW2
LED1
LED2
SHDN SGND/
CTRL4 AGND SS1
FB4
SS4 CT
0.1µF
0.1µF 4.99
0.1µF
Si2301BDS
1M
AVDD
5V
40mA
4.7µF
20mA 20mA
1942 TA01
1942fb
1


Linear Technology Electronic Components Datasheet

LT1942 Datasheet

Quad DC/DC Converter

No Preview Available !

LT1942
ABSOLUTE AXI U RATI GS
(Note 1)
VCC 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
VOUT3 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
UW U
PACKAGE/ORDER I FOR ATIO
TOP VIEW
24 23 22 21 20 19
PGND23 1
SW3 2
D3 3
VOUT3 4
FB3 5
NFB2 6
18 LED1
17 LED2
16 D4
25
15 FB4
14 FB1
13 PGOOD
7 8 9 10 11 12
ORDER PART
NUMBER
LT1942EUF
UF PART
MARKING
1942
UF PACKAGE
24-LEAD (4mm × 4mm) PLASTIC QFN
TJMAX = 125°C, θJA = 37°C/W, θJC = 4.3°C/W
EXPOSED PAD (PIN 25) IS SGND
(MUST BE SOLDERED TO PCB)
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/
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS The denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VIN = 3.3V, VSHDN = VIN, unless otherwise noted. (Note 2)
PARAMETER
CONDITIONS
MIN TYP MAX
UNITS
Quiescent Current
Input Voltage Range
AVDD Feedback Voltage
AVDD Feedback Pin Bias Current (FB1)
AVDD Feedback Voltage for Power Good Signal
VOFF Feedback Voltage
VOFF Feedback Pin Bias Current (NFB2)
VON Feedback Voltage
VON Feedback Pin Bias Current (FB3)
LED Feedback Voltage
LED Feedback Pin Bias Current (FB4)
VSHDN = 3.3V, VCTRL4 = 0V, Not Switching
VSHDN = VCTRL4 = 0V, In Shutdown
VCC Pin
FB1 Pin
FB1 Pin (Note 3)
FB1 Pin Voltage as a Percent of Nominal Voltage
NFB2 Pin
NFB2 Pin (Note 3)
FB3 Pin
FB3 Pin (Note 3)
FB4 Pin, VCTRL4 = 3.3V
FB4 Pin (Note 3)
2.6
1.225
95
–160
1.225
190
7
0
1.25
15
97
–150
25
1.25
25
200
20
10
1
16
1.275
60
100
–140
60
1.275
60
210
60
mA
µA
V
V
nA
%
mV
nA
V
nA
mV
µA
LED Feedback Voltage with Dimming
FB4 Pin, VCTRL4 = 1V
85 95 105
mV
1942fb
2


Part Number LT1942
Description Quad DC/DC Converter
Maker Linear
PDF Download

LT1942 Datasheet PDF






Similar Datasheet

1 LT1940 1.1MHz Step-Down Switching Regulator
Linear Technology
2 LT1940L 1.1MHz Step-Down Switching Regulator
Linear
3 LT1941 Triple Monolithic Switching Regulator
Linear Technology
4 LT1942 Quad DC/DC Converter
Linear
5 LT1943 High Current Quad Output Regulator
Linear
6 LT1944-1 Dual Micropower Step-Up DC/DC Converter
Linear
7 LT1945 Dual Micropower DC/DC Converter
Linear Technology
8 LT1946 1.2MHz Boost DC/DC Converter
Linear Technology
9 LT1946A 2.7MHz Boost DC/DC Converter
Linear Technology





Part Number Start With

0    1    2    3    4    5    6    7    8    9    A    B    C    D    E    F    G    H    I    J    K    L    M    N    O    P    Q    R    S    T    U    V    W    X    Y    Z

Site map

Webmaste! click here

Contact us

Buy Components

Privacy Policy