TC1266
2.0 PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 2-1.
TABLE 2-1: PIN FUNCTION TABLE
Pin No.
(8-Pin SOIC)
(8-Pin MSOP)
1
2
3
4
5
6
7
8
Symbol
Description
VIN
NC
VAUX
GND
NC
SENSE
VOUT
DR
Main input supply for the TC1266, nominally 5V.
Not connected.
Auxiliary input supply, nominally 3.3V.
Logic and power ground.
Not connected.
Sense pin for VOUT. Connect to VOUT at the load to minimize voltage drop across PCB traces.
LDO 3.3V output.
Driver output for external P-channel MOSFET pass element.
3.0 DETAILED DESCRIPTION
FIGURE 3-1:
APPLICATION CIRCUIT
Q1
5V
3.3V
C2
4.7µF
C1
0.1µF
C3
0.1µF
U1
1 VIN
DR 8
2 NC TC1266 VOUT 7
3 VAUX
SENSE 6
4
GND
NC 5
C4
4.7µF
NOTE: External switch (Q1): use Motorola MGSF1P02ELT1 or equivalent
(PMOS, typical Gate Threshold Voltage = 1V, typical RDS(ON) = 0.4Ω at VGS = 2.5V)
C5
0.1µF
3.3V
DS21377B-page 4
© 2002 Microchip Technology Inc.