LTC3450 Datasheet, PDF (1/12 Pages) Linear Technology – Triple Output Power Supply for Small TFT-LCD Displays

LTC3450
Triple Output Power Supply
for Small TFT-LCD Displays
FEATURES
s _{Generates Three Voltages:}
5.1V at 10mA
– 5V, –10, or –15V at 500µA
10V or 15V at 500µA
s _{Better than 90% Efficiency}
s _{Low Output Ripple: Less than 5mVP-P}
s _{Complete 1mm Component Profile Solution}
s _{Controlled Power-Up Sequence: AVDD/VGL/VGH}
s _{All Outputs Disconnected and Actively Discharged in}
Shutdown
s _{Low Noise Fixed Frequency Operation}
s _{Frequency Reduction Input for High Efficiency in}
Blank Mode
s _{Ultralow Quiescent Current: 75µA (Typ) in Scan Mode}
s _{Available in a 3mm × 3mm 16-Pin QFN Package}
U
APPLICATIO S
s _{Cellular Handsets with Color Display}
s _{Handheld Instruments}
s _PDA
DESCRIPTIO
The LTC^®3450 is a complete power converter solution for
small thin film transistor (TFT) liquid crystal display (LCD)
panels. The device operates from a single Lithium-Ion cell,
2- to 3-cell alkaline input or any voltage source between
1.5V and 4.6V.
The synchronous boost converter generates a low noise,
high efficiency 5.1V, 10mA supply. Internal charge pumps
are used to generate 10V, 15V, and –5V, –10V or –15V.
Output sequencing is controlled internally to insure proper
initialization of the LCD panel.
A master shutdown input reduces quiescent current to
<2µA and quickly discharges each output for rapid turn off
of the LCD panel. The LTC3450 is offered in a low profile
(0.8mm max), 3mm × 3mm 16-pin QFN package, mini-
mizing the solution profile and footprint.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
V_IN
1.5V TO
4.6V
5.1V, –10V, 15V Triple Output TFT-LCD Supply
47µH
2.2µF
BLANK SCAN
OFF ON
8
7
6 ^SW
V_IN
V_OUT
C1
+
11
C1^{– 10}
4
MODE
12
V2X
LTC3450 C2^{+ 14}
5 _SHDN
C2^{– 13}
V3X ¹⁵
9 _GND
V_NEG
C3^– C3^{+VINV 16}
3 21
2.2µF
0.1µF
0.1µF
AV_DD
5.1V/10mA
0.47µF
VGH (3 × AV_DD)
15V/500µA
0.1µF
0.1µF
0.1µF
VGL
–10V/500µA
3450 TA01
AV_DD Efficiency vs V_IN
100
5mA LOAD
95
100µH
90
47µH
85
80
75
70
1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
V_IN (V)
3450 TA01b
3450f
1