Datasheet ADP2311 (Analog Devices)

Dual 1 A, 18 V, Synchronous Step-Down Regulator with Fail-Safe Voltage Monitoring Data Sheet ADP2311 FEATURES TYPICAL APPLICATION CIRCUIT Input voltage: 4.5 V to 18 V ±1.0% output accuracy PFO POR WDI RSTO VIN EN Integrated MOSFET: 110 mΩ/60 mΩ typical PVIN1 PVIN2 VIN RPFI_TOP RVM2_TOP Continuous output current: 1 A/1 A CIN1 PFI VM2 CIN2 RPFI_BOT RVM2_BOT Power fail comparator generates warning Power-on reset with programmable delay timer BST1 ADP2311 BST2 C1 C2 BST BST Adjustable voltage monitor for power-down (Channel 2) V L2 VOUT2 OUT1 L1 SW1 SW2 Watchdog refresh input PGND1 PGND2 C RTOP1 R COUT2 OUT1 TOP2 Dual phase with 180° out-of-phase operation FB1 FB2 RBOT1 R Fixed switching frequency: 300 kHz GND VREG TIMER BOT2
001
Internal compensation and soft start CVREG CTIMER
1036- 1
Stable with low ESR output ceramic capacitors
Figure 1.
Precision enable input 100 Power feedback during power-off VOUT = 3.3V 95 VOUT = 5V UVLO, OCP, OVP, and thermal shutdown protection 90 APPLICATIONS 85 Industrial and instrumentation ) 80 (% Healthcare and medical Y C N 75 DC-to-DC point of load applications IE C 70 FFI E 65 60 55 50 0 0.2 0.4 0.6 0.8 1.0
002
OUTPUT CURRENT (A)
1036- 1 Figure 2. Efficiency vs. Output Current at VIN = 12 V, fSW = 300 kHz
GENERAL DESCRIPTION
The ADP2311 is a fully integrated, dual output, synchronous An on-chip watchdog timer can reset the microprocessor if it step-down dc-to-dc regulator. The regulator operates from input fails to strobe within a preset timeout period. Accurate voltage voltages of 4.5 V to 18 V, and the output can regulate down to monitoring circuitry and a power fail comparator provide a 0.6 V. Each channel can provide up to 1 A of continuous output control ed power-up and power-down sequence to enhance current. system reliability. The ADP2311 integrates the high-side and low-side MOSFETs The ADP2311 also includes undervoltage lockout (UVLO), to provide a very high efficiency, compact solution. Both channels overvoltage protection (OVP), overcurrent protection (OCP), of the regulator run at 180° out of phase to reduce the input ripple and thermal shutdown (TSD). current and the input capacitor size, thereby helping to lower The ADP2311 operates over the −40°C to +125°C junction system electromagnetic interference (EMI). The ADP2311 also temperature range and is available in a 24-lead LFCSP package. integrates internal compensation and soft start circuitry to simplify the design.
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Document Outline Features Applications Typical Application Circuit General Description Revision History Functional Block Diagram Specifications Absolute Maximum Ratings Thermal Resistance ESD Caution Pin Configuration and Function Descriptions Typical Performance Characteristics Theory of Operation Control Scheme Precision Enable/Shutdown Internal Regulator (VREG) Bootstrap Circuitry Soft Start Peak Current-Limit and Short-Circuit Protection Power-On Reset (POR) TIMER Pin Configuration Power Fail Comparator Voltage Monitor Comparator (VM2) Watchdog Timer Power-Up and Power-Down Sequence Overvoltage Protection (OVP) Undervoltage Lockout (UVLO) Thermal Shutdown Applications Information Input Capacitor Selection Output Voltage Setting Inductor Selection Output Capacitor Selection Application Circuit Outline Dimensions Ordering Guide