LT3430/LT3430-1
High Voltage, 3A,
200kHz/100kHz Step-Down
Switching Regulators
FEATURES DESCRIPTION
Wide Input Range: 5.5V to 60V
The LT 3430/LT3430-1 are monolithic buck switching
3A Peak Switch Current over All Duty Cycles
regulators that accept input voltages up to 60V. A high ef-
Constant Switching Frequency:
ciency 3A, 0.1 switch is included on the die along with
200kHz (LT3430)
all the necessary oscillator, control and logic circuitry. A
100kHz (LT3430-1)
current mode architecture provides fast transient response
0.1 Switch Resistance
and excellent loop stability.
Current Mode
Special design techniques and a new high voltage process
Effective Supply Current: 2.5mA
achieve high ef ciency over a wide input range. Ef ciency
Shutdown Current: 30A
is maintained over a wide output current range by using
1.2V Feedback Reference Voltage
the output to bias the circuitry and by utilizing a supply
Easily Synchronizable
boost capacitor to saturate the power switch. Patented
Cycle-by-Cycle Current Limiting
circuitry* maintains peak switch current over the full duty
Small, 16-Pin Thermally Enhanced TSSOP Package
cycle range. A shutdown pin reduces supply current to
30A and a SYNC pin can be externally synchronized with
APPLICATIONS
a logic level input from 228kHz to 700kHz for the LT3430
Industrial and Automotive Power Supplies
or from 125kHz to 250kHz for the LT3430-1.
Portable Computers
The LT3430/LT3430-1 are available in a thermally enhanced
Battery Chargers
16-pin TSSOP package.
Distributed Power Systems
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
*US Patent # 6498466
TYPICAL APPLICATION
5V, 2A Buck Converter Ef ciency vs Load Current
100
MMSD914TI
V = 5V
OUT
V = 12V
IN
90
0.68F
BOOST
V 22H
V
IN OUT
5.5V* V SW 5V
IN
80
V = 42V
TO 60V 2A IN
30BQ060
4.7F
LT3430**
100V
+ 100F 10V
70
SOLID
OFF ON SHDN BIAS
TANTALUM
15.4k
60
SYNC FB
LT3430-1 L = 68H
GND V 4.99k
C
LT3430 L =27H
50
0 0.5 1.0 1.5 2.0 2.5
LOAD CURRENT (A)
220pF
3.3k
3430 TA02
0.022F
3430 TA01
*FOR INPUT VOLTAGES BELOW 7.5V, SOME RESTRICTIONS MAY APPLY
** SEE LT3430-1 CIRCUIT IN APPLICATIONS INFORMATION SECTION
34301fa
1
EFFICIENCY (%)LT3430/LT3430-1
ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION
(Note 1)
TOP VIEW
Input Voltage (V ) .................................................. 60V
IN
GND 1 16 GND
BOOST Pin Above SW (Note 11) .............................. 35V
SW 2 15 SHDN
BOOST Pin Voltage ................................................. 68V
V 3 14 SYNC
IN
SYNC Voltage ............................................................. 7V
V 4 13 NC
IN
17
SHDN Voltage ............................................................ 6V
SW 5 12 FB
BIAS Pin Voltage ..................................................... 30V
BOOST 6 11 V
C
FB Pin Voltage/Current .................................. 3.5V/2mA
NC 7 10 BIAS
Operating Junction Temperature Range
GND 8 9 GND
LT3430EFE (Notes 8, 10) .................. 40C to 125C
FE PACKAGE
16-LEAD PLASTIC TSSOP
LT3430IFE (Notes 8, 10) .................. 40C to 125C
T = 125C, = 45C/W, = 10C/W
JMAX JA JC
Storage Temperature Range ................. 65C to 150C
EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB
Lead Temperature (Soldering, 10 sec) ................ 300C
ORDER PART NUMBER FE PART MARKING
LT3430EFE 3430EFE
LT3430IFE 3430IFE
LT3430EFE-1 3430EFE-1
LT3430IFE-1 3430IFE-1
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: