Texas Instruments LM3248, User Manual, Page: 12 / 17

Pin Descriptions
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14 Pin Descriptions
Pin # Name I/O Description
Power supply voltage input for Boost Analog blocks. Connected to VBATT
A1 VDD_BOOST -
supply.
A2
PVIN_BOOST - Power supply voltage input for Boost Bypass FET.
A3
A4 Boost converter output. When Boost and Buck are active, OUT_BOOST
must be externally connected to PVIN_BUCK. A 10 µF capacitor must be
OUT_BOOST 0
placed between this node and GND. Internally connected to BUCK voltage
A5
input and feedback to inverting input of Boost error amplifier.
Digital input. A Low to High transition wakes up the boost converter and
B1 BOOST_GATE I
positions it to a high level in preparation for a possible VCON change.
B2 SGND_BOOST - Analog Ground for the Boost Analog blocks.
B3
Boost converter switch node. When Boost and Buck are active, SW_BOOST
B4 SW_BOOST I/O
is typically connected to VBATT supply through external power inductor.
B5
C1 MODE I Digital input. Low = 3G/4G operation; High = 2G operation.
Power supply voltage input for Buck Analog PWM blocks. Internally
C2 VDD1_BUCK -
connected to PVIN_BUCK when used with Boost.
C3 SGND_BUCK - Analog Ground for the Buck Analog Blocks.
C4
C5 PGND - Power Ground for output FETs.
F3
Input. Chip enable. Setting ENABLE = High biases up the Buck and initiates
D1 ENABLE I
VCON regulation by the Buck.
D2 VCON I Analog voltage control input which controls Buck output voltage.
D3 NC - No Connect; leave this pin floating.
D4
SW_BUCK 0 Buck converter switch node for external filter inductor connection
D5
E1 ATB1 - Test pin. Connect to SGND or System Ground.
Feedback input to inverting input of error amplifier. Connect Buck output
E2 FB_BUCK -
voltage directly to this node.
E3 DGND - Ground for Boost, Buck and digital blocks.
E4 Power supply input for Buck PFET and ACB FET. A 10 µF capacitor must be
PVIN_BUCK - placed between this node and PGND. Must be externally connected to
E5
OUT_BOOST.
F1 ATB2 - Test pin. Connect to SGND or System Ground.
Power supply voltage input for Buck Analog PWM blocks. Internally
F2 VDD2_BUCK -
connected to PVIN_BUCK when used with Boost.
F4
Active Current Assist and Bypass output. Connected to the Buck converter
ACB -
output filter capacitor.
F5
12 LM3248 2.7MHz, 2.5A Boost-Buck DC/DC Converter Evaluation Module SNAA196 – September 2013
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