TPS2104, TPS2105
VAUX POWER-DISTRIBUTION SWITCHES
SLVS235A – SEPTEMBER 1999 – REVISED APRIL 2000
4
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
Terminal Functions
TERMINAL
NO.
DESCRIPTION
NAME
TPS2104
TPS2105
I/O
DESCRIPTION
DBV
D
DBV
D
EN
1
3
I
Active-high enable for IN1-OUT switch
EN
1
3
I
Active-low enable for IN1-OUT switch
GND
2
I
Ground
IN1
5
I
Main input voltage, NMOS drain (250 m
), require 0.22 F bypass
IN2
3
1
3
1
I
Auxilliary input voltage, PMOS drain (1.3
), require 0.22 F bypass
OUT
4
7, 8
4
7, 8
O
Power switch output
NC
4, 6
No connection
Unused INx should not be grounded.
detailed description
power switches
n-channel MOSFET
The IN1-OUT n-channel MOSFET power switch has a typical on-resistance of 250 m
at 5-V input voltage, and
is configured as a high-side switch.
p-channel MOSFET
The IN2-OUT p-channel MOSFET power switch has a typical on-resistance of 1.3
at 5-V input voltage and
is configured as a high-side switch. When operating, the p-channel MOSFET quiescent current is reduced to
typically 0.75
A.
charge pump
An internal charge pump supplies power to the driver circuit and provides the necessary voltage to pull the gate
of the MOSFET above the source. The charge pump operates from input voltages as low as 2.7 V and requires
very little supply current.
driver
The driver controls the gate voltage of the IN1-OUT and IN2-OUT power switches. To limit large current surges
and reduce the associated electromagnetic interference (EMI) produced, the drivers incorporate circuitry that
controls the rise times and fall times of the output voltage.
enable
The logic enable will turn on the IN2-OUT power switch when a logic high is present on EN (TPS2104) or logic
low is present on EN (TPS2105). A logic low input on EN (TPS2104) or logic high on EN (TPS2105) restores
bias to the drive and control circuits and turns on the IN1-OUT power switch. The enable input is compatible
with both TTL and CMOS logic levels.