900,000+ datasheet pdf search and download

Datasheet4U offers most rated semiconductors data sheet pdf




Linear Technology Electronic Components Datasheet

LT1425 Datasheet

Isolated Flyback Switching Regulator

No Preview Available !

LT1425
Isolated Flyback
Switching Regulator
FEATURES
s No Transformer “Third Winding” or Optoisolator
Required
s ±5% Accurate Output Voltage Without User Trims
(See Circuit Below)
s Resistor Programmable Output Voltage
s Regulation Maintained Well Into Discontinuous
Mode (Light Load)
s Optional Load Compensation
s Operating Frequency: 285kHz
s Easily Synchronized to External Clock
s Available in 16-Pin Narrow SO Package
U
APPLICATIONS
s Isolated Flyback Switching Regulators
s Ethernet Isolated 5V to – 9V Converters
s Medical Instruments
s Isolated Telecom Supplies
, LTC and LT are registered trademarks of Linear Technology Corporation.
DESCRIPTION
The LT®1425 is a monolithic high power switching regu-
lator specifically designed for the isolated flyback topol-
ogy. No “third winding” or optoisolator is required; the
integrated circuit senses the isolated output voltage
directly from the primary side flyback waveform. A high
current, high efficiency switch is included on the die along
with all oscillator, control and protection circuitry.
The LT1425 operates with input supply voltages from 3V
to 20V and draws only 7mA quiescent current. It can
deliver output power up to 6W with no external power
devices. By utilizing current mode switching techniques, it
provides excellent AC and DC line regulation.
The LT1425 has a number of features not found on other
switching regulator ICs. Its unique control circuitry can
maintain regulation well into discontinuous mode in most
applications. Optional load compensation circuitry allows
for improved load regulation. An externally activated shut-
down mode reduces total supply current to 15µA for
standby operation.
TYPICAL APPLICATION
5V to Isolated – 9VOUT
500V
ISOLATION BARRIER
5V
+ C1
100µF
10V
T1*
12
VIN 11
VSW
R1
D1
1N5819
C2
47µF
16V
V
ISOLATED
–9V ± 5% AT
20mA TO 200mA
LT1425
22.6k
F
15
3 1%
*DALE LPE 4841-330MB
SHDN
6
RFB
R2
SYNC
3.01k
4
C3
1000pF
VC RREF
ROCOMP
RCCOMP
SGND PGND
5
14
13
1%
C4
0.1µF
R3
15k
7 10
1425 TA01
9.5
9.4
9.3
9.2
9.1
9.0
8.9
8.8
8.7
8.6
8.5
0
Load Regulation
50 100 150
OUTPUT CURRENT (mA)
200
1425 TA02
1


Linear Technology Electronic Components Datasheet

LT1425 Datasheet

Isolated Flyback Switching Regulator

No Preview Available !

LT1425
ABSOLUTE MAXIMUM RATINGS
(Note 1)
Supply Voltage ........................................................ 20V
Switch Voltage ......................................................... 35V
SHDN, SYNC Pin Voltage ........................................... 7V
RFB Pin Current....................................................... 2mA
Operating Junction Temperature Range
Commercial .......................................... 0°C to 100°C
Industrial ......................................... – 40°C to 100°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
PACKAGE/ORDER INFORMATION
GND 1
NC 2
RFB 3
VC 4
RREF 5
SYNC 6
SGND 7
GND 8
TOP VIEW
16 GND
15 SHDN
14 ROCOMP
13 RCCOMP
12 VIN
11 VSW
10 PGND
9 GND
S PACKAGE
16-LEAD PLASTIC SO
TJMAX = 145°C, θJA = 75°C/ W
Consult factory for Military grade parts.
ORDER PART
NUMBER
LT1425CS
LT1425IS
ELECTRICAL CHARACTERISTICS VIN = 5V, TJ = 25°C, VSW open, VC = 1.4V, unless otherwise specified.
SYMBOL
PARAMETER
CONDITIONS
MIN TYP MAX
Feedback Amplifier
IREF Reference Current
Measured at RFB Pin with RREF = 3.000k
402 408 414
q 396
420
IIN
gm
ISOURCE, ISINK
VCL
RREF Pin Input Current
Feedback Amplifier Transconductance
Feedback Amplifier Source or Sink Current
Feedback Amplifier Clamp Voltage
Reference Voltage/Current Line Regulation
Voltage Gain
IC = ±10µA (Note 2)
5V VIN 18V
(Note 3)
q 400
q 30
q
500
1000 1600
50 80
1.9
0.01 0.04
500
VIN Sense Error
Output Switch
q 10 25
BV
V(VSW)
ILIM
Output Switch Breakdown Voltage
Output Switch ON Voltage
Switch Current Limit
IC = 5mA
q 35
50
ISW = 1A
q 0.55 0.85
Duty Cycle = 50%, 0°C TJ 100°C
Duty Cycle = 50%, – 40°C TJ 100°C
Duty Cycle = 80%
q 1.35
q 1.25
1.60
1.60
1.30
1.9
1.9
Current Amplifier
Control Pin Threshold
Duty Cycle = Minimum
0.95
q 0.85
1.2
1.3
1.4
Control Voltage to Switch Transconductance
2
Timing
f Switching Frequency
260 285 300
q 240
320
tON Minimum Switch ON Time
tED Flyback Enable Delay Time
tEN Minimum Flyback Enable Time
Maximum Switch Duty Cycle
170 210 260
150
180
q 85 90 95
UNITS
µA
µA
nA
µmho
µA
V
%/ V
V/ V
mV
V
V
A
A
A
V
V
A/V
kHz
kHz
ns
ns
ns
%
2


Part Number LT1425
Description Isolated Flyback Switching Regulator
Maker Linear Technology
PDF Download

LT1425 Datasheet PDF






Similar Datasheet

1 LT1424-5 Isolated Flyback Switching Regulator with 5V Output
Linear Technology
2 LT1424-9 Isolated Flyback Switching Regulator with 9V Output
Linear Technology
3 LT1425 Isolated Flyback Switching Regulator
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