Datasheet LTM4634 (Analog Devices) - 10

LTM4634
operaTion Power Module Description
is cleared. There are two temperatures monitors in the The LTM4634 µModule regulator is a high performance LTM4634. TEMP1 monitors the close relative tempera- triple output nonisolated switching mode DC/DC power ture of channels 1 and 2, and TEMP2 monitors the close supply. It can provide 5A/5A/4A outputs with a few ex- relative temperature of channels 2 and 3. The two diode ternal input and output capacitors. This module provides connected PNP transistors are grounded in the module precisely regulated output voltages programmable via and can be used as general purpose temperature monitors external resistors from 0.8V DC to 5.5V DC (V using a device that is designed to monitor the single-ended OUT1 and V connection. OUT2), and 0.8V DC to 13.5V DC (VOUT3). When apply- ing control bias in the range from 4.75V to 5.8V, then Pulling any of the RUN pins below 1.15V forces that connect the bias to CNTL_PWR and INTVCC, otherwise regulator channel into a shutdown state. The TK/SS pins if >5.8V only the CNTL_PWR pin needs to be biased. The are used for programming the output voltage ramp and typical application schematic is shown in Figure 22. voltage tracking during start-up for each of the channels. The LTM4634 has three integrated constant-frequency cur- See the Applications Information section. rent mode regulators, power MOSFETs, power inductors, The LTM4634 is internally compensated to be stable over all and other supporting discrete components. The typical operating conditions. Table 4 provides a guideline for input switching frequency is 750kHz. For switching noise- and output capacitances for several operating conditions. sensitive applications, it can be externally synchronized The LTpowerCAD™ software tool is provided for transient from 250kHz to 750kHz. Operating frequency range will and stability analysis. The VFB pin is used to program the be dependent upon specific VIN and VOUT requirements output voltage with a single external resistor to ground. as they pertain to minimum on-time and inductor ripple Each of the channels, operate 120° phase shift for mul- current of less than 60% of the load current. See the Ap- tiphase operation. V plications Information section. OUT1 and VOUT2 can be combined to provide a single 10A output. The two channels will not be With current mode control and internal feedback loop operating 180° phase shift, but 120° phase when combined compensation, the LTM4634 module has sufficient stabil- for a 10A design. So the input RMS current may be higher ity margins and good transient performance with a wide than a 180° phase shifted design. See the Applications range of output capacitors, even with all ceramic output Information section for details. capacitors. High efficiency at light loads can be accomplished with Current mode control provides cycle-by-cycle fast current selectable Burst Mode operation using the MODE/PLLIN limit in an overcurrent condition. An internal overvoltage pin. These light load features will accommodate battery monitor protects the output voltages in the event of an operation. Efficiency graphs are provided for light load op- overvoltage >10%. The top MOSFET is turned off and the eration in the Typical Performance Characteristics section. bottom MOSFET is turned on until the output overvoltage 4634f 10 For more information www.linear.com/LTM4634 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Related Parts