Datasheet

1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16
32 31 30 29 28 27 26
OUT12
GND
OREM
PASS
SENM
SET
GND NC GND EN12 GND EN3 GND
VINT
GND
GND
PG12
SUM12
FLT12
CT12
BLK
PowerPAD
TM
SENP
IN12
NC
TPS2458
(Top View)
24
23
22
21
20
19
18
17
25
AGND
VDD3
SUM3
PG3
FLT3
CT3
OUT3
IN3
3-V
Inputs
12-V Inputs
12-V
Inputs
TPS2458
www.ti.com SLUS916B –FEBRUARY 2009–REVISED MAY 2010
DEVICE INFORMATION
Figure 1.
TERMINAL FUNCTIONS
NAME NO. I/O
Analog ground. Ground pin for the analog circuitry insideBypass capacitor connection point for internal supply
AGND 24 —
the TPS2458.
12-V blocking transistor gate drive. Gate drive pin for the 12-V channel BLK FET. This pin sources 30 mA to
BLK 8 O turn the FET on. An internal clam prevents this pin from rising more than 14.5 V above OUT12. Setting the
OREN pin high holds the BLK pin low.
12-V fault timing capacitor. A capacitor from CT12 to GND sets the time the channel can remain in current
limit before it shuts down and declares a fault. Current limit causes this pin to source 10 mA into the external
CT12 7 I/O
capacitor (CT ). When V
CT12
reaches 1.35 V, the TPS2458 shuts the channel off by pulling the FET gate low
and declares an overcurrent fault by pulling the FLT12 pin low
3-V fault timing capacitor. A capacitor from CT3 to GND sets the time the channel can remain in current limit
before it shuts down and declares a fault. Current limit causes this pin to source 10 mA into the external
CT3 19 I/O
capacitor (CT ). When V
CT3
reaches 1.35 V, the TPS2458 shuts the channel off by pulling the FET gate low
and declares an overcurrent fault by pulling the FLT3 pin low.
12-V enable. (active low). Pulling this pin high (or allowing it to float high) turns off the 12-V channel by pulling
EN12 28 I
both BLK and PASS low. An internal 200-kΩ resistor pulls this pin up to VINT when disconnected.
3-V enable. (active low) Pulling this pin high (or allowing it to float high) turns off the 3-V channel by pulling the
EN3 26 I gate of the internal pass FET to GND. An internal 200-kΩ resistor pulls this pin up to VINT when
disconnected.
12-V fault output (active low) Open-drain output indicating that channel 12 has remained in current limit long
FLT12 6 O
enough to time out the fault timer and shut the channel down. asserted when 12-V fault timer runs out
3-V fault output (active low) Open-drain output indicating that channel 3 has remained in current limit long
FLT3 20 O
enough to time out the fault timer and shut the channel down. asserted when 3-V fault timer runs out
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Product Folder Link(s): TPS2458