Datasheet
LT3489
1
3489f
A
VDD
LOAD CURRENT (mA)
0
EFFICIENCY (%)
65
70
75
300
500
3489 TA01b
60
55
50
100 200 400
80
85
90
700600
V
ON
LOAD = 10mA
V
OFF
LOAD = 20mA
2MHz Boost DC/DC
Converter with 2.5A Switch
and Soft-Start
The LT
®
3489 is a fi xed frequency step-up DC/DC converter
containing an internal 2.5A, 40V switch. The LT3489 is
ideal for large TFT-LCD panel power supplies. The LT3489
switches at 2MHz, allowing the use of tiny, low profi le
inductors and low value ceramic capacitors. Loop com-
pensation can be either internal or external, giving the
user fl exibility in setting loop compensation and allow-
ing optimized transient response with low ESR ceramic
output capacitors. Soft-start is controlled with an external
capacitor, which determines the input current ramp rate
during start-up.
The 8-lead MS8E package and high switching frequency en-
sure a low profi le overall solution less than 1.1mm high.
■
TFT-LCD Bias Supplies
■
GPS Receivers
■
DSL Modems
■
Local Power Supply
■
2.5A, 0.12Ω, 40V Internal Switch
■
2MHz Switching Frequency
■
Integrated Soft-Start Function
■
V
IN
Range: 2.6V to 16V
■
Adjustable Output from V
IN
to 40V
■
Low V
CESAT
Switch: 110mV at 1A (Typical)
■
8V at 610mA from a 3.3V Input
■
Internal or External Loop Compensation
■
Small 8-Lead MS8E
Low Profi le, Triple Output TFT Supply (8V, –8V, 23V)
APPLICATIO S
U
FEATURES
DESCRIPTIO
U
TYPICAL APPLICATIO
U
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
V
IN
V
IN
3.3V
SW
FB
LT3489
2.2µH
5.23k
37.4k
28.7k
3489 TA01
20µF
220pF
0.1µF
0.1µF 0.1µF
2µF
2µF
4.7µF
100nF
V
OFF
–8V
20mA
AV
DD
8V
610mA
V
ON
23V
10mA
0.1µF
V
C
GND
SHDN
SS
COMP
+
OFF ON
Effi ciency