Datasheet

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1 Description
The TPS51220 is a dual, peak-current mode, synchronous step-down controller with three low-dropout
(LDO) regulators. It is optimized for 5-V /3.3-V notebook system power supplies. A 99% duty cycle
operation enables designers to complete Li-ion battery applications from 2-cells to 4-cells cost effectively.
The TPS51220 supports high-efficiency, fast transient response and 99% duty cycle operation. DCR
current sensing provides lossless current sensing and free MOSFET selection; resistor sensing supports
accurate current-sensing operation. It supports supply input voltages ranging from 4.5 V to 30 V and
output voltages from 1 V to 12 V. High-current, 5 V at 100 mA, 3.3 V at 10 mA, onboard linear regulators
have glitch-free switchover function to SMPS, and the 2-V reference has a 100-μA capability.
A peak current-sensing current mode and fixed-frequency control scheme support the full range of current
mode operation including simplified loop compensation, ceramic output capacitors, as well as a seamless
transition to reduced frequency operation at light-load condition.
This evaluation module demonstrates the performance of the high-current/ high-efficiency TPS51220 buck
converter
2 Electrical Performance
SPECIFICATIONS TEST CONDITIONS MIN TYP MAX UNIT
Input voltage range (VIN) 8 12 20 V
CH1 Output voltage 5 V
Operating frequency VIN = 12 V, Iout1 = 6 A 280 kHz
Output current VIN = 8 V to 20 V 6 A
Over current limit VIN = 12 V 9 A
Output ripple voltage VIN = 12 V, Iout1 = 6 A 15 mVp-p
CH2 Output voltage 3.3 V
Operating frequency VIN = 12 V, Iout2 = 6 A 280 kHz
Output current VIN = 8 V to 20 V 6 A
Over current limit VIN = 12 V 9 A
Output ripple voltage VIN = 12 V, Iout2 = 6 A 15 mVp-p
2
High-Performance Synchronous Buck EVM Using the TPS51220 SLVU251A–June 2008–Revised May 2011
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