900,000+ datasheet pdf search and download

Datasheet4U offers most rated semiconductors data sheet pdf




Linear Technology Electronic Components Datasheet

LT1939 Datasheet

Monolithic 2A Step-Down Regulator Plus Linear Regulator/Controller

No Preview Available !

FEATURES
n Wide Input Range: 3V to 25V
n Short-Circuit Protected Over Full Input Range
n 2A Output Current Capability
n Adjustable/Synchronizable Fixed Frequency
Operation from 250kHz to 2.2MHz
n Soft-Start/Tracking Capability
n Output Adjustable Down to 0.8V
n Adjustable Linear Regulator/Driver with 13mA
Output Capability
n Power Good Comparator with Complementary
Outputs
n Low Shutdown Current: 12μA
n Thermally Enhanced 3mm × 3mm DFN Package
APPLICATIONS
n Automotive Battery Regulation
n Industrial Control
n Wall Transformer Regulation
n Distributed Power Regulation
LT1939www.DataSheet4U.com
Monolithic 2A Step-Down
Regulator Plus Linear
Regulator/Controller
DESCRIPTION
The LT®1939 is a current mode PWM step-down DC/DC
converter with an internal 2.3A switch. The wide input
range of 3V to 25V makes the LT1939 suitable for regu-
lating power from a wide variety of sources, including
automotive batteries, industrial supplies and unregulated
wall adapters.
Resistor-programmable 250kHz to 2.2MHz frequency
range and synchronization capability enable optimization
between efficiency and external component size. Cycle-
by-cycle current limit, frequency foldback and thermal
shutdown provide protection against a shorted output.
The soft-start feature controls the ramp rate of the output
voltage, eliminating input current surge during start-up,
and also provides output tracking.
The LT1939 contains an internal NPN transistor with feed-
back control which can be configured as a linear regulator
or as a linear regulator controller.
The LT1939’s low current shutdown mode (<12μA) enables
easy power management in battery-powered systems.
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
Dual Step-Down Converters
VIN
6V TO 25V
2.2μF
0.47μF
VIN BST
LT1939
SW
SHDN
SS
FB
PG
PG
BAT54
0.47μF
6.8μH
B240A
42.2k
8.06k
VOUT1
5V
1A
22μF
53.6k
330pF
40.2k
RT/SYNC LDRV
VC
LFB
1k
24.9k
8.06k
VOUT2
3.3V
22μF 1A
1939 TA01a
Switching Converter Efficiency
90
85
80 VOUT1 = 5V AT 1A
AC COUPLED
75 2mV/DIV
70
65
60
55
VIN = 12V
IOUT2 = 0A
FREQUENCY = 800kHz
50
0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
LOAD CURRENT (A)
1939 TA01b
VOUT2 = 3.3V AT 1A
AC COUPLED
2mV/DIV
Output Voltage Ripple
500ns/DIV
1939 TA01c
1939f
1


Linear Technology Electronic Components Datasheet

LT1939 Datasheet

Monolithic 2A Step-Down Regulator Plus Linear Regulator/Controller

No Preview Available !

LT1939
www.DataSheet4U.com
ABSOLUTE MAXIMUM RATINGS
(Note 1)
VIN, PG, PG Operating.................................... 25V/–0.3V
SW .............................................................................VIN
BST ................................................................ 45V/–0.3V
BST Pin Above SW....................................................25V
LDRV, SHDN..............................................................15V
FB, LFB, RT/SYNC .......................................................5V
SS, VC ......................................................................2.5V
Operating Junction Temperature Range (Notes 2, 6)
LT1939EDD........................................ –40°C to 125°C
LT1939IDD......................................... –40°C to 125°C
Storage Temperature Range................... –65°C to 150°C
PIN CONFIGURATION
TOP VIEW
VIN
SHDN
SS
PG
VC
RT/SYNC
1
2
3
4
5
6
12 SW
11 BST
13 10 LDRV
9 LFB
8 FB
7 PG
DD PACKAGE
12-LEAD (3mm × 3mm) PLASTIC DFN
θJA = 45°C/W, θJC(PAD) = 10°C/W
EXPOSED PAD (PIN 13) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LT1939EDD#PBF
LT1939IDD#PBF
LT1939EDD#TRPBF
LT1939IDD#TRPBF
LDJZ
LDJZ
12-Lead (3mm × 3mm) Plastic DFN
12-Lead (3mm × 3mm) Plastic DFN
–40°C to 125°C
–40°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TJ = 25°C. VVIN = 15V, VRT/SYNC = 2V, unless otherwise specified.
PARAMETER
CONDITIONS
MIN TYP MAX UNITS
SHDN Threshold
l 710 760 780
mV
SHDN Source Current
1.5 2.5 3.5
μA
SHDN Current Hysterisis
1.25 2 3.25
μA
Minimum Input Voltage (Note 3)
Supply Shutdown Current
Supply Quiescent Current
FB Voltage
FB Bias Current
Error Amplifier gm
Error Amplifier Source Current
Error Amplifier Sink Current
Error Amplifier High Clamp
Error Amplifier Switching Threshold
SS Source Current
VFB = 0V
VSHDN = 0V
VFB = 0.9V
VVC = 1V
VVC = 0.6V to 1.6V, VIN = 3V to 25V
VFB = 0.8V, VVC = 1V
VVC = 1V, IVC = ±10μA
VFB = 0.6V, VVC = 1V
VFB = 1V, VVC = 1V
VFB = 0.6V
VFB = 0.6V
VSHDN = 1V, VSS = 0.4V, VFB = 0.9V
l
2.4 2.8
V
l
12 30
μA
2.5 3.5
mA
l 0.784 0.8 0.816
l 0.776 0.8 0.824
V
V
50 150
nA
150 250 350 μmho
12 16 20
μA
14 18 22
μA
1.8 2.0 2.2
V
0.6 0.8 1.0
V
2.25 2.75 3.75
μA
1939f
2


Part Number LT1939
Description Monolithic 2A Step-Down Regulator Plus Linear Regulator/Controller
Maker Linear Technology
PDF Download

LT1939 Datasheet PDF





Similar Datasheet

1 LT1930 1A/ 1.2MHz/2.2MHz/ Step-Up DC/DC Converters
Linear Technology
2 LT1930A Constant-Current/ Constant-Voltage 1.4MHz Step-Up DC/DC Converter
Linear Technology
3 LT1931 1.2MHz/2.2MHz Inverting DC/DC Converters
Linear Technology
4 LT1931A 1.2MHz/2.2MHz Inverting DC/DC Converters
Linear Technology
5 LT1932 Constant-Current DC/DC LED Driver
Linear Technology
6 LT1933 Step-Down Switching Regulator
Linear Technology
7 LT1934 Micropower Step-Down Switching Regulators in ThinSOT
Linear Technology
8 LT1934-1 Micropower Step-Down Switching Regulators in ThinSOT
Linear Technology
9 LT1935 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