Datasheet LTC7851, LTC7851-1 (Analog Devices) - 6

LTC7851/LTC7851-1
TYPICAL PERFORMANCE CHARACTERISTICS Line Step Transient Response Efficiency vs Load Current Efficiency vs Load Current (2-Phase Using FDMF5820DC (2-Phase Using D12S1R8130A (4-Phase Using D12S1R8130A DrMOS) Power Block) Power Block)
100 100 VIN 10V/DIV 90 90 7V TO 14V 80 80 IL1 70 70 10A/DIV 60 60 IL2 50 50 10A/DIV 40 40 VOUT EFFICIENCY (%) EFFICIENCY (%) 50mV/DIV 30 30 AC-COUPLED 20 fSW = 400kHz 7851 G05 f 20 SW = 400kHz V 20µs/DIV IN = 12V 10 VIN = 12V 10 V V OUT = 1.2V OUT = 1.2V VOUT = 1.2V Airflow ≈ 400LFM ILOAD = 15A 0 0 0 10 20 30 40 50 60 70 0 20 40 60 80 100 120 140 LOAD CURRENT (A) LOAD CURRENT (A) 3681 G06 3681 G07
Feedback Voltage VFB vs Start-Up Response (2-Phase Temperature Regulated VFB vs Supply Voltage Using FDMF5820DC DrMOS)
602 602 RUN 5V/DIV 601 601 IL1 TAGE (mV) TAGE (mV) 20A/DIV VOL 600 VOL I FB 600 FB L2 20A/DIV TED V TED V VOUT 599 599 1V/DIV CSS = 0.1µF REGULA REGULA 5ms/DIV 7851 G10 VIN = 12V 598 598 VOUT = 1.2V –50 –25 0 25 50 75 100 125 3 3.5 4 4.5 5 5.5 RLOAD = 0.037Ω TEMPERATURE (°C) SUPPLY VOLTAGE (V) fSW = 400kHz 7851 G08 7851 G09
Start-Up Response Start-Up Response (3-Phase (4-Phase Using D12S1R8130A Coincident Tracking (Single Phase Using FDMF5820DC DrMOS) Power Block) Using FDMF5820DC DrMOS)
RUN VIN = 12V 5V/DIV RUN VOUT = 1.8V I 4V/DIV L1 20A/DIV TRACK/SS IL2 500mV/DIV 20A/DIV I I L3 LOAD 20A/DIV 50A/DIV VOUT VOUT V 1V/DIV 1V/DIV INTERNAL SOFT-START OUT 1V/DIV INTERNAL RLOAD = 0.01Ω RLOAD = 27mΩ SOFT–START fSW = 400kHz 7851 G11 7851 G12 7851 G13 V 400µs/DIV IN = 12V 500µs/DIV 2ms/DIV VOUT = 1.2V VIN = 12V VOUT = 1.2V RLOAD = 0.017Ω fSW = 400kHz Rev A 6 For more information www.analog.com Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Typical Application Related Parts