Datasheet LTC3774 (Analog Devices)

LTC3774 Dual, Multiphase Current Mode Synchronous Controller for Sub-Milliohm DCR Sensing
FEATURES DESCRIPTION
n
Sub-Milliohm DCR Current Sensing
The LTC®3774 is a dual PolyPhase® current mode syn- n
Operates with Power Blocks, DRMOS or External
chronous step-down switching regulator controller that
Gate Drivers and MOSFETs
drives power blocks, DRMOS or external gate drivers and n
Supports Phase Shedding and N+1 Phase
power MOSFETs. It offers an LTC-proprietary technique
Redundancy
that enhances the signal-to-noise ratio of the current n
Programmable DCR Temperature Compensation
sense signal, allowing the use of inductors with very low n
±0.75% Maximum Total DC Output Error Over
DC winding resistances as the current sense element for
Temperature
maximum efficiency and reduced jitter. n
Dual Differential Remote Output Voltage Sense
The maximum current sense voltage is programmable
Amplifiers
from 10mV to 30mV. High speed, low offset remote sense n
Phase-Lockable Fixed Frequency Range: 200kHz to
differential amplifiers and a precise 0.6V reference provide
1.2MHz
accurate output voltages between 0.6V and 3.5V from a wide n VIN Range: 4.5V to 38V 4.5V to 38V input supply range. Soft recovery from output n VOUT Range: 0.6V to 3.5V shorts or overcurrent minimizes output overshoot. Burst n Supports Smooth Start-Up into Pre-Biased Outputs Mode® operation, continuous and pulse-skipping modes n Programmable Soft-Start or VOUT Tracking are supported. The constant operating frequency can be n Hiccup Mode/Soft Recovery from Output Overcurrent synchronized to an external clock or linearly programmed n 36-Lead (5mm × 6mm) QFN Package from 200kHz to 1.2MHz. Up to six LTC3774 controllers can be paralleled for 1-, 2-, 3-, 4-, 6-, 8- or 12-phase operation.
APPLICATIONS
The LTC3774 is available in a 36-lead (5mm × 6mm) QFN n Computer Systems package. n Telecom and Datacom Systems L, LT, LTC, LTM, Linear Technology, the Linear logo, PolyPhase and Burst Mode are registered n Industrial Equipment trademarks and No RSENSE and Hot Swap are trademarks of Analog Devices, Inc. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including n DC Power Distribution Systems 5481178, 5705919, 5929620, 6177787, 6580258, 6498466, 6611131, patent pending.
TYPICAL APPLICATION High Efficiency Dual Phase 1.5V/60A Step-Down Converter
VIN 4.5V TO 20V 22µF RUN1, 2 VIN PHSMD 50V 1/4 INTVCC ILIM1, 2 CLKOUT HIZB1 PGOOD1,2 0.33µH HIZB2 MODE/PLLIN fIN 0.33µH (0.32mΩ DCR) LTC3774 500kHz (0.32mΩ DCR) DRMOS PWM1 PWM2 DRMOS PWMEN1 PWMEN2 GND V – – OSNS1 VOSNS2 SNSA1+ SNSA2+ SNS1– SNS2– SNSD1+ SNSD2+ 15k FREQ VOUT V + + OSNS1 VOSNS2 1.5V ITH1 ITH2 60A 2200pF TK/SS1 TK/SS2 INTVCC + 10k + 300µF 37.5k 330µF 4V 15k 4V 0.1µF 4.7µF 3774 TA01a 3774fc For more information www.linear.com/LTC3774 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Block Diagram Operation Applications Information Typical Applications Package Description Typical Application Related Parts