Document
Data Sheet
2 A/1.25 A, 1.2 MHz, Synchronous, Step-Down DC-to-DC Regulators ADP2119/ADP2120
FEATURES
Continuous output current ADP2119: 2 A ADP2120: 1.25 A
145 mΩ and 70 mΩ integrated MOSFETs Input voltage range from 2.3 V to 5.5 V Output voltage from 0.6 V to VIN ±1.5% output accuracy 1.2 MHz fixed switching frequency Synchronizable between 1 MHz and 2 MHz Selectable PWM or PFM mode operation Current mode architecture Precision threshold enable input Power-good flag Voltage tracking Integrated soft start Internal compensation Startup with precharged output UVLO, OVP, OCP, and thermal shutdown 10-lead, 3 mm × 3 mm LFCSP_WD package Supported by ADIsimPower™ design tool
APPLICATIONS
Point of load conversion Communications and networking equipment Industrial and instrumentation Consumer electronics Medical applications
GENERAL DESCRIPTION
The ADP2119/ADP2120 are low quiescent current, synchronous, step-down dc-to-dc regulators in a compact 3 mm × 3 mm LFCSP_WD package. Both devices use a current mode, constant frequency pulse-width modulation (PWM) control scheme for excellent stability and transient response. Under light load conditions, they can be configured to operate in a pulse frequency modulation (PFM) mode, which reduces switching frequency to save power.
The ADP2119/ADP2120 support input voltages from 2.3 V to 5.5 V. The output voltage can be adjusted from 0.6 V up to the input voltage (VIN) for the adjustable version, whereas the fixed output version is available in preset output voltage options of 3.3 V, 2.5 V, 1.8 V, 1.5 V, 1.2 V, and 1.0 V. The ADP2119/ADP2120 require minimal external parts and provide a high efficiency solution with their integrated power switches, synchronous rectifiers, and internal compensation. Each IC draws less than 2 µA current from the input source when it is disabled. Other key features include undervoltage lockout (UVLO), integrated soft start to limit inrush current at startup, overvoltage protection (OVP), overcurrent protection
Rev. A
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TYPICAL APPLICATION CIRCUIT
C1 0.1µF
VIN
5V
CIN
22µF
X5R
6.3V
R1
10Ω ADP2119/ADP2120
1 VIN
EN 10
VOUT 3.3V
COUT 22µF X5R 6.3V
RBOT 2.21kΩ
L 1.5µH
RTOP 10kΩ
2 PVIN 3 SW
SYNC/MODE 9 R2
10kΩ PGOOD 8
4 PGND
TRK 7
5 GND
FB 6
Figure 1.
08716-001
EFFICIENCY (%)
08716-002
(OCP), and thermal shutdown (TSD).
100 VIN = 5V
90 VOUT = 1.8V
80
70 PFM
60
50
40
FPWM 30
20
10
0 0.01
0.1
1
OUTPUT CURRENT (A)
Figure 2. ADP2119 Efficiency vs. Output Current
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ADP2119/ADP2120
TABLE OF CONTENTS
Features .............................................................................................. 1 Applications....................................................................................... 1 Typical Application Circuit ............................................................. 1 General Description ......................................................................... 1 Revision History ............................................................................... 2 Specifications..................................................................................... 3 Absolute Maximum Ratings............................................................ 5
Thermal Resistance ...................................................................... 5 Boundary Condition .................................................................... 5 ESD Caution.................................................................................. 5 Pin Configuration and Function Descriptions............................. 6 Typical Performance Characteristics ............................................. 7 Functional Block Diagram ............................................................ 15 Theory of Operation ...................................................................... 16 Control Scheme .......................................................................... 16 PWM Mode Operation.............................................................. 16 PFM Mode Operation................................................................ 16 Slope Compensation .................................................................. 16 Enable/Shutdown ....................................................................... 16
REVISION HISTORY
8/12—Rev. 0 to Rev. A Change t.