LT3489_15 Datasheet, PDF (1/12 Pages) Linear Technology – 2MHz Boost DC/DC Converter with 2.5A Switch and Soft-Start

FEATURES
■ _{2.5A, 0.12Ω, 40V Internal Switch}
■ _{2MHz Switching Frequency}
■ _{Integrated Soft-Start Function}
■ _{VIN Range: 2.6V to 16V}
■ _{Adjustable Output from VIN to 40V}
■ _{Low VCESAT Switch: 110mV at 1A (Typical)}
■ _{8V at 610mA from a 3.3V Input}
■ _{Internal or External Loop Compensation}
■ _{Small 8-Lead MS8E}
U
APPLICATIO S
■ _{TFT-LCD Bias Supplies}
■ _{GPS Receivers}
■ _{DSL Modems}
■ _{Local Power Supply}
LT3489
2MHz Boost DC/DC
Converter with 2.5A Switch
and Soft-Start
DESCRIPTIO
The LT^®3489 is a fixed 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 profile
inductors and low value ceramic capacitors. Loop com-
pensation can be either internal or external, giving the
user flexibility 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 profile overall solution less than 1.1mm high.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATIO
Low Profile, Triple Output TFT Supply (8V, –8V, 23V)
V_ON
23V
10mA
0.1µF
0.1µF
0.1µF
V_IN
3.3V
OFF ON
+
4.7µF
100nF
2.2µH
V_IN
SW
SHDN
SS LT3489
COMP
FB
V_C
GND
37.4k
220pF
28.7k
5.23k
AV_DD
8V
610mA
20µF
2µF
0.1µF
2µF
V_OFF
–8V
3489 TA01 _20mA
Efficiency
90
85
80
75
70
65
60
55 _{VON LOAD = 10mA}
50 ^{VOFF LOAD = 20mA}
0 100 200 300 400 500 600 700
A_VDD LOAD CURRENT (mA)
3489 TA01b
3489f
1