Datasheet

1
2
3
4
5
10
9
8
7
6
PGOOD
TRIP
EN
VFB
RF
VBST
DRVH
SW
V5IN
DRVL
TPS51218DSC
GND
DSC PACKAGE
(TOP VIEW)
TRIP
OCL
V
V
8
=
TPS51218
SLUS935B –MAY 2009–REVISED FEBRUARY 2012 www.ti.com
DEVICE INFORMATION
Thermal pad is used as an active terminal of GND.
PIN FUNCTIONS
PIN
I/O DESCRIPTION
NAME NO.
High-side MOSFET driver output. The SW node referenced floating driver. The gate drive voltage is
DRVH 9 O
defined by the voltage across VBST to SW node bootstrap flying capacitor
Synchronous MOSFET driver output. The GND referenced driver. The gate drive voltage is defined by
DRVL 6 O
V5IN voltage.
EN 3 I SMPS enable pin. Short to GND to disable the device.
Thermal
GND I Ground
Pad
Power Good window comparator open drain output. Pull up with resistor to 5 V or appropriate signal
PGOOD 1 O voltage. Continuous current capability is 1 mA. PGOOD goes high 1 ms after VFB becomes within
specified limits. Power bad, or the terminal goes low, after a 2- μs delay.
Switching frequency selection. Connect a resistance to select switching frequency as shown in Table 1.
The switching frequency is detected and stored into internal registers during startup. This pin also controls
RF 5 I Auto-skip or forced CCM selection.
Pull down to GND with resistor : Auto-Skip
Connect to PGOOD with resistor: forced CCM after PGOOD becomes high.
Switch node. A high-side MOSFET gate drive return. Also used for on time generation and output
SW 8 I
discharge.
OCL detection threshold setting pin. 10 μA at room temperature, 4700 ppm/°C current is sourced and set
the OCL trip voltage as follows.
TRIP 2 I
(0.2 V ≤ V
TRIP
≤ 3 V)
V5IN 7 I 5 V +30%/–10% power supply input.
Supply input for high-side MOSFET driver (bootstrap terminal). Connect a flying capacitor from this pin to
VBST 10 I
the SW pin. Internally connected to V5IN via bootstrap MOSFET switch.
VFB 4 I SMPS feedback input. Connect the feedback resistor divider.
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