Datasheet

TPS51123A
SLUSAA6C –APRIL 2011–REVISED SEPTEMBER 2012 www.ti.com
DEVICE INFORMATION
Table 2.
TERMINAL
I/O DESCRIPTION
NAME NO.
DRVH1 21
O High-side N-channel MOSFET driver outputs. LL referenced drivers.
DRVH2 10
DRVL1 19
O Low-side N-channel MOSFET driver outputs. GND referenced drivers.
DRVL2 12
Master enable input.
EN0 13 I/O Open : LDOs on, and ready to turn both switcher channels.
GND : disable all circuit
Channel 1 and Channel 2 enable input. Pull up to the voltage ranging 3.3-V to 5-V to turn on both
ENC 18 I
switcher channels. Short to ground to shutdown them.
GND 15 – Ground.
LL1 20
I Switch node connections for high-side drivers, current limit and control circuitry.
LL2 11
PGOOD 23 O Powergood window comparator output for channel 1 and 2. (Logical AND)
Selection pin for operation mode:
OOA auto skip : Connect to VREG3 or VREG5
SKIPSEL 14 I
PWM only: Connect to VREF
Auto skip: Connect to GND
TRIP1 1
Channel 1 and Channel 2 enable and OCL trip setting pins. Connect resistor from this pin to GND to
I/O
set threshold for synchronous R
DS(on)
sense. Short to ground to shut down a switcher channel.
TRIP2 6
On-time adjustment pin.
365 kHz/460 kHz setting: connect to VREG5
TONSEL 4 I 300 kHz/375 kHz setting: connect to VREG3
245 kHz/305 kHz setting: connect to VREF
200 kHz/250 kHz setting: connect to GND
VBST1 22
I Supply input for high-side N-channel MOSFET driver (boost terminal).
VBST2 9
VFB1 2
I SMPS feedback inputs. Connect with feedback resistor divider.
VFB2 5
VIN 16 I High voltage power supply input for 5-V/3.3-V LDO.
VO1 24
Output connection to SMPS. These terminals work as fixed voltage inputs and output discharge
I/O
inputs. VO1 and VO2 also work as 5-V and 3.3-V switch over return power input respectively.
VO2 7
2-V reference voltage output. Connect a high-quality X5R or X7R ceramic capacitor with a value
VREF 3 O
between 220-nF and 1-µF to signal GND near the device.
3.3-V power supply output. Connect a high-quality X5R or X7R ceramic capacitor with a value of 10-
VREG3 8 O
µF or larger to power GND near the device. A 1-μF ceramic capacitor is acceptable when not loaded.
5-V power supply output. Connect a high-quality X5R or X7R ceramic capacitor with a value of 10-µF
VREG5 17 O
or larger to power GND near the device.
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