TK732xx
APPLICATION INFORMATION (CONT.)
EXTERNAL PNP POWER TRANSISTOR
This IC can use any kind of external transistor. The external transistor selection is a function of the load current, Hfe and
power dissipation. See following chart:
LOAD CURRENT
RECOMMENDED EXTERNAL TRANSISTOR
0 ~ 180 mA
2SB624, 2SB1115, 2SB799 (NEC), 2SB970 (Matushita)
0 ~ 300 mA
2SB1115, 2SB799 (NEC)
0 ~ 500 mA
2SB1114, 2SB1115 (NEC), 2SB1302 (Sanyo), 2SA1203,
2SA1213, 2SA1734 (Toshiba)
0~1A
2SA1242, 2SA1736 (Toshiba), 2SB1302, 2SA1896 (Sanyo)
0~2A
2SA1451, 2SA1242 (Toshiba)
0~3A
2SA1451 (Toshiba), 2SA1645 (NEC)
0~4A
2SA1451 (Toshiba), 2SB904 (Sanyo), 2SA1645 (NEC)
RECOMMENDED RIPK (Ω)
0.33 ~ 0.39
0.22 ~ 0.27
0.12 ~ 0.15
0.056 ~ 0.068
0.033 ~ 0.039
0.022 ~ 0.027
0.012 ~ 0.015
HIGH-SIDE SWITCHING
VOLTAGE
REGULATOR
VDROP
ON/OFF
CONTROL
VOUT
High-side switching should not be implemented by an external transistor as shown above. This results in additional
voltage drop and loss of accuracy.
µ PRO
VIN
TK732xx
VCONT
VOUT
The high output voltage accuracy and low dropout voltage are maintained when the IC is turned ON/OFF by using the
control pin as illustrated above.
January 1999 TOKO, Inc.
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