Datasheet LTC3897-2 (Analog Devices)

link to page 13 LTC3897-2 PolyPhase® Synchronous Boost Controller with Input/Output Protection
FEATURES DESCRIPTION
n
Input Supply Range: 4.5V to 65V (Up to 75V Surge)
The LTC®3897-2 is a synchronous boost DC/DC controller n
Reverse Input Protection to –40V
with surge stopper and ideal diode controller. n
Inrush Current Control, Overcurrent Protection and
The boost controller drives two N-channel power MOSFET
Output Disconnect for Boost Converter
stages out-of-phase to reduce input and output capacitor n
Input Voltage Surge Protection with Adjustable
requirements, allowing the use of smaller inductors than
Clamp Voltage
the single-phase equivalent. Synchronous rectification n
Onboard Ideal Diode Controller
reduces power loss and eases thermal requirements. n
Low Quiescent Current: 55µA
n
2-Phase Operation Reduces Required Input and
The surge stopper controls the gate of an external N-channel
Output Capacitance and Noise
MOSFET to protect against high voltage input transients and n
Output Voltage Up to 60V
provides inrush current control, overcurrent protection and n
Adjustable Gate Drive Level 5V to 10V (OPTI-DRIVE)
output disconnect for the boost converter. The integrated
for Logic-Level or Standard Threshold FETs
ideal diode controller drives another N-channel MOSFET to n
No External Bootstrap Diodes Required
replace a Schottky diode for reverse input protection and n 5mm × 9mm QFN-44 Package with High Voltage voltage holdup or peak detection. It controls the forward Pin Spacing voltage drop across the MOSFET and minimizes reverse current flow.
APPLICATIONS
The differences between the LTC3897-2 and LTC3897 are n shown in Table 1. Industrial All registered trademarks and trademarks are the property of their respective owners. Protected n Automotive by U. S. Patents, including 5408150, 5481178, 5705919, 5929620, 6144194, 6177787, n 6580258. Military/Avionics n Telecommunications
TYPICAL APPLICATION 24V/10A 2-Phase Synchronous Boost Converter with Surge Protection and Reverse Protection Efficiency and Power Loss
REVERSE CURRENT PROTECTION (IDEAL DIODE)
vs Output Current
INPUT VOLTAGE SURGE PROTECTION 5mΩ 3.5µH REVERSE INPUT VOLTAGE PROTECTION IN-RUSH/OVERCURRENT PROTECTION 100 100k BURST EFFICIENCY V 90 IN 2mΩ VBIAS SENSE1+ 6V TO 80 10k 55V 33µF 549k SENSE1– POWER LOSS (mW) 70 SPFB BG1 0.1µF 10Ω 60 1k 12.1k BURST LOSS BOOST1 50 10nF IS– SW1 40 100 IS+ TG1 EFFICIENCY (%) 30 DG 5mΩ 3.5µH VOUT V 24V IN = 12V CS SENSE2+ 20 V 10 10A OUT = 24V SG LTC3897-2 SENSE2– 10 Burst Mode OPERATION V FIGURE 17 CIRCUIT IN BG2 220µF 0.1µF RUN 0.1µF 0 1 0.001 0.01 0.1 1 10 SS BOOST2 OUTPUT CURRENT (A) 15nF 38972 TA01b 8.66k SW2 ITH 1µF TG2 475k INTV PINS NOT SHOWN IN THIS CIRCUIT: CC VFB PLLIN/MODE, I DRV 38972 TA01a LIM, PHASMD, CC 4.7µF 24.9k CLKOUT, EXTVCC, SGEN, DGEN DRVSET DTC VIN OPERATES THROUGH TRANSIENTS UP TO 75V. DRVUV FREQ GND TMR WHEN VIN > 24V, VOUT FOLLOWS VIN UP TO 57V. 1nF Rev. A Document Feedback For more information www.analog.com 1 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 Typical Application Related Parts