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LM21215A
SNOSB87D – MARCH 2011 – REVISED MAY 2019
LM21215A 2.95-V to 5.5-V,15-A, Voltage-Mode Synchronous Buck Converter With Frequency Synchronization
1 Features
•1 High-Efficiency Synchronous DC/DC Converter – Input Voltage Range of 2.95 V to 5.5 V – Adjustable Output Voltage From 0.6 V to VIN – Output Current as High as 15 A
• Frequency Synchronization 300 kHz to 1.5 MHz • Integrated 7-mΩ PMOS Buck Switch Supports
100% Duty Cycle for Low Dropout Voltage • Integrated 4.3-mΩ NMOS Synchronous Rectifier
Eliminates Schottky Diode • Accurate ±1% Internal Voltage Reference • Automatic Diode Emulation Mode for Improved
Efficiency at Light Loads • Monotonic Pre-Biased Startup • Internal 0.5-ms or Externally Adjustable Soft Start • Output Voltage Tracking Capability • Ultra-Fast Line and Load Transient Response
– Voltage-Mode PWM Control – Wide-Bandwidth Voltage Loop Error Amplifier • Precision Enable with Hysteresis • Integrated OVP, UVP, OCP, and UVLO • Open-Drain Power Good Indicator • Thermal Shutdown Protection With Hysteresis • Thermally-Enhanced HTSSOP-20 Package • Create a custom design using the LM21215A with the WEBENCH® Power Designer
2 Applications
• Telecommunications Infrastructure • DSP and FPGA Core Voltage Supplies • High Efficiency POL Conversion • Embedded Computing, Servers and Storage
Efficiency at 2.5 V, 500 kHz
100
98
EFFICIENCY (%)
96
94
92 90
0
VIN = 3.3V VIN = 4.0V VIN = 5.0V VIN = 5.5V
3
6
9
12 15
OUTPUT CURRENT (A)
3 Description
The LM21215A is a synchronous buck DC-DC converter that delivers up to 15 A of output current at output voltages as low as 0.6 V. Operating over an input voltage range of 2.95 V to 5.5 V with ultra-high efficiency, the LM21215A suits a wide variety of low voltage systems. The voltage-mode control loop with high gain-bandwidth error amplifier provides high noise immunity, narrow duty cycle capability and is easily compensated for stable operation with any type of output capacitor, providing maximum flexibility and ease of use.
The LM21215A features internal overvoltage protection (OVP) and cycle-by-cycle overcurrent protection (OCP) for increased system reliability. A precision enable pin and integrated UVLO allow turnon of the device to be tightly controlled and sequenced. Startup inrush currents are limited by an internally-fixed or externally-adjustable soft-start circuit. An integrated open-drain PGOOD indicator provides fault reporting and supply sequencing.
Other features include auxiliary voltage rail tracking, monotonic startup into pre-biased loads, and switching frequency synchronization to an external clock signal between 300 kHz and 1.5 MHz for beatfrequency sensitive and multi-regulator applications. The LM21215A is offered in a thermally-enhanced 20-pin HTSSOP package with an exposed pad that is soldered to the PCB to achieve a very low junction-toboard thermal impedance.
Device Information(1)
PART NUMBER
PACKAGE
BODY SIZE (NOM)
LM21215A
HTSSOP (20)
6.50 mm × 4.40 mm
(1) For all available packages, see the orderable addendum at the end of the data sheet.
VIN CIN
Typical Application Circuit
5,6,7 PVIN
LF
SW 11Å16
RF CF
optional
optional
CSS
4 AVIN
3 LM21215A-1 EN 19 FB
2 SS/TRK
18 COMP
RFB1 CC1 RC1
CC2
CC3 RC2
1 SYNC
PGOOD 17
PGOOD
PGND AGND
8,9,10
20
VOUT COUT
RFB2
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA.
LM21215A
SNOSB87D – MARCH 2011 – REVISED MAY 2019
www.ti.com
Table of Contents
1 Features .................................................................. 1 2 Applications ........................................................... 1 3 Description ............................................................. 1 4 Revision History..................................................... 2 5 Pin Configuration and Functions ......................... 3 6 Specifications......................................................... 4
6.1 Absolute Maximum Ratings ...................................... 4 6.2 ESD Ratings.............................................................. 4 6.3 Recommended Operating Conditions....................... 4 6.4 Thermal Information .................................................. 4 6.5 Electrical Characteristics........................................... 5 6.6 Typical Characteristics .............................................. 7 7 Detailed Description ............................................ 11 7.1 Overview ................................................................. 11 7.2 Functional Block Diagram ....................................... 11 7.3 Feature Description................................................. 12
7.4 Device Functional Modes.........