Datasheet LTM4671 (Analog Devices) - 14

link to page 30 LTM4671
DECOUPLING REQUIREMENTS SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
CIN External Input Capacitor Requirement 44 66 µF (VIN = 3.1V to 20V, VOUT = 1.5V) COUT0, COUT3 External Output Capacitor Requirement IOUT = 12A 100 200 µF (VIN = 3.1V to 20V, VOUT = 1.5V) COUT1, COUT2 External Output Capacitor Requirement IOUT = 5A 22 47 µF (VIN = 3.1V to 20V, VOUT = 1.5V)
OPERATION
The LTM4671 is a quad output standalone non-isolated employ a 2+1+1 or 2+2 channels parallel operation which switch mode DC/DC power supply. It has built-in four is more than flexible in a multirail POL application like separate regulator channels which can deliver 12A, 12A, FPGA. Furthermore, the LTM4671 has CLKIN and CLKOUT 5A, 5A continuous output current with few external input pins for frequency synchronization or PolyPhase multiple and output capacitors. Two 12A regulator provides pre- devices which allow up to 8 phases of 12A or 5A channels cisely regulated output voltage programmable from 0.6V can be cascaded to run simultaneously. to 3.3V via a single external resistor over 3.1V to 20V input voltage range while the other two 5A regulator can Current mode control also provides cycle-by-cycle fast cur- support output voltage from 0.6V to 5.5V. Dual true dif- rent monitoring. An internal overvoltage and undervoltage ferential remote sensing amplifiers are included in the high comparators pull the open-drain PGOOD output low if the current channels to get accurate regulation at load point. output feedback voltage exits a ±10% window around the The typical application schematic is shown in Figure 30. regulation point. Furthermore, in an overvoltage condition, internal top FET is turned off and bottom FET is turned on The LTM4671 has integrated four separate constant on- and held on until the overvoltage condition clears. time valley current mode regulators, power MOSFETs, inductors, and other supporting discrete components. Pulling the RUN pin below 0.6V forces the controller into For switching noise-sensitive applications, the switching its shutdown state, turning off both power MOSFETs and frequency can be adjusted by external resistors and the most of the internal control circuitry. At light load currents, µModule can be externally synchronized to a clock. See Burst Mode operation can be enabled to achieve higher the Applications Information section. efficiency compared to continuous mode for the dual 5A channels by setting MODE/PLLIN pin floating or tying With current mode control and internal feedback loop to INTVCC. The TRACK/SS pin is used for power supply compensation, the LTM4671 module has sufficient stabil- tracking and soft-start programming. See the Applications ity margins and good transient performance with a wide Information section. range of output capacitors, even with all ceramic output capacitors. For Dual 12A output rails, an optional Type II Three different temperature sensing pins are included in- C-R-C external compensation network is allowed to cus- side the module to monitor the temperature of the module tomize the stability and transient performance. for different channels. See the Applications Information section for details. Current mode control provides the flexibility of paralleling any of the separate regulator channels with accurate cur- rent sharing. With a build in clock interleaving between each two regulator channels, the LTM4671 could easily Rev. B 14 For more information www.analog.com Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Decoupling Requirements Operation Applications Information Typical Applications Component BGA Pinout Package Description Revision History Package Photo Related Parts