Datasheet LTM4614 (Analog Devices) - 7

LTM4614
Decoupling requireMenTs TA = 25°C. Use Figure 1 configuration for each channel. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
CIN External Input Capacitor Requirement IOUT = 4A 22 µF (VIN = 2.375V to 5.5V, VOUT = 1.5V) COUT External Output Capacitor Requirement IOUT = 4A 100 µF (VIN = 2.375V to 5.5V, VOUT = 1.5V)
operaTion LTM4614 POWER MODULE DESCRIPTION
open-drain PGOOD outputs low if the particular output The LTM4614 is a standalone dual nonisolated switching feedback voltage exits a ±7.5% window around the regu- mode DC/DC power supply. It can deliver up to 4A of DC lation point. Furthermore, in an overvoltage condition, output current for each channel with few external input internal top FET, M1, is turned off and bottom FET, M2, and output capacitors. This module provides two precisely is turned on and held on until the overvoltage condition regulated output voltages programmable via one external clears, or current limit is exceeded. resistor for each channel from 0.8V DC to 5V DC over Pulling each specific RUN pin below 0.8V forces the spe- a 2.375V to 5.5V input voltage. The typical application cific regulator controller into its shutdown state, turning schematic is shown in Figure 12. off both M1 and M2 for each power stage. At low load The LTM4614 has two integrated constant frequency cur- current, each regulator works in continuous current mode rent mode regulators, with built-in power MOSFETs with by default to achieve minimum output voltage ripple. fast switching speed. The typical switching frequency is The TRACK and RUN/SS pins are used for power supply 1.25MHz. With current mode control and internal feedback tracking and soft-start programming for each specific loop compensation, these switching regulators have suf- regulator. See the Applications Information section. ficient stability margins and good transient performance The LTM4614 is internally compensated to be stable over under a wide range of operating conditions and with a the operating conditions. Table 4 provides a guideline for wide range of output capacitors, even all ceramic output input and output capacitance for several operating con- capacitors. ditions. The LTpowerCAD™ GUI is available for transient Current mode control provides cycle-by-cycle fast current and stability analysis. limit. Besides, current limiting is provided in an overcur- The FB pins are used to program the specific output volt- rent condition with thermal shutdown. In addition, inter- age with a single externally connected resistor to ground. nal overvoltage and undervoltage comparators pull the 4614fb 7 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Simplified Block Diagram Decoupling Requirements Operation Applications Information Package Description Revision History Package Photograph Related Parts