Datasheet
SLVS317 − MAY 2001
24
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
APPLICATION INFORMATION
12-V flash memory supply
The TPS6734 is a fixed 12-V output boost converter capable of delivering 120 mA from inputs as low as 2.7 V.
The device is pin-for-pin compatible with the MAX734 regulator and offers the following advantages: lower
supply current, wider operating input-voltage range, and higher output currents. As shown in Figure 36, the only
external components required are: an inductor, a Schottky rectifier, an output filter capacitor, an input filter
capacitor, and a small capacitor for loop compensation. The entire converter occupies less than 0.7 in
2
of PCB
space when implemented with surface-mount components. An enable input is provided to shut the converter
down and reduce the supply current to 3 µA when 12 V is not needed.
The TPS6734 is a 170-kHz current-mode PWM (pulse-width modulation) controller with an n-channel MOSFET
power switch. Gate drive for the switch is derived from the 12-V output after start-up to minimize the die area
needed to realize the 0.7-Ω MOSFET and improve efficiency at input voltages below 5 V. Soft start is
accomplished with the addition of one small capacitor. A 1.22-V reference, pin 2 of TPS6734, is brought out for
external use. For additional information, see the TPS6734 data sheet (SLVS127).
NOTE A: The enable terminal can be tied to a general-purpose I/O terminal on the PCMCIA controller or tied high.
TPS2226 or
TPS2224
BVPP
BVCC
BVCC
BVCC
†
AVPP
AVCC
†
AVCC
AVCC
LATCH
CLOCK
DATA
OC
RESET
3.3 V
5 V
12 V
3.3 V
†
5 V
12 V
3.3 V
3.3 V
5 V
5 V
SHDN
0.1 µF
0.1 µF1 µF
0.1 µF4.7 µF
EN
REF
SS
COMP
TPS6734
VCC
FB
OUT
GND
1
2
3
4
L1
18 µH
8
7
6
5
R1
10 kΩ
Enable
(see Note A)
C1
33 µF
20 V
C2
0.01 µF
12 V
D1
33 µF, 20 V
C4
0.001 µF
3.3 V or 5 V
+
C1
+
†
Not on TPS2224
Figure 36. TPS2224 and TPS2226 with TPS6734 12-V, 120-mA Supply