DEMO MANUAL DC1543B LTM4641 38V, 10A, Step-Down Module Regulator with Advanced Input and Load Protection DESCRIPTION Demonstration circuit 1543B features the LTM 4641, a protection input latching/non-latching overvoltage protec- high efficiency, high density switch mode step-down power tion and latching/non-latching overtemperature protection. Module regulator with superior input and load protection Higher efficiency at low load currents is achieved by setting features. The input voltage range is from 4.5V to 38V. The the MODE pin jumper to DCM. The LTM4641 data sheet output voltage is jumper programmable from 0.8V to 6V must be read in conjunction with this demo manual prior with a rated load current of 10A. Derating is necessary to working on or modifying demo circuit 1543B. for certain V , V , frequency and thermal conditions. IN OUT Design files for this circuit board are available. DC1543B offers the TRACK/SS pin allowing the user to All registered trademarks and trademarks are the property of their respective owners. program output tracking or soft-start period. The DC1543B allows the user to enable/disable input undervoltage PERFORMANCE SUMMARY PARAMETER CONDITIONS VALUE Input Voltage Range 4.5V to 38V Output Voltage V Jumper Selectable 0.8V, 1.0V, 1.2V, 1.5V, 1.8V, 3.3V, 5V, 6V 1.5% OUT Maximum Continuous Output Current Derating is Necessary for Certain Operating Conditions. 10A DC See Data Sheet for Details. Default Operating Frequency R = 680k for V = 0.8V, 1.0V, 1.2V, 1.5V, 1.8V 255kHz (V = 0.8V) 320kHz (V = 1.0V) fSET OUT OUT OUT R = (Not Stuffed) for V = 3.3V, 5.0V, 6.0V 385kHz (V = 1.2V) 480kHz (V = 1.5V) fSET OUT OUT OUT 575kHz (V = 1.8V) 360kHz (V = 3.3V) OUT OUT 550kHz (V = 5.0V) 660kHz (V = 6.0V) OUT OUT Efficiency V = 12V, V = 6V, I = 10A 93.0% See Figure2 IN OUT OUT Load Transient V = 12V, V = 3.3V See Figure3 IN OUT BOARD PHOTO Rev. 0 1DEMO MANUAL DC1543B QUICK START PROCEDURE Demonstration circuit 1543B is an easy way to evaluate parameters. Output voltage ripple may be measured at the performance of the LTM4641. Please refer to Figure1 J6 with a BNC cable and oscilloscope. The probe channel for proper measurement equipment setup and follow the for V should be set at 50 termination resistance OUT procedure below: to match the BNC cable. 1. Place jumpers in the following positions for a typical 5. (Optional) For optional load transient test, apply an 3.3V application: adjustable pulse signal between IOSTEP CLK and GND OUT test points. The pulse amplitude sets the load step cur- INPUT NON-LATCH INPUT INPUT UVLO OVER-TEMP rent amplitude. Keep the pulse width short (<1ms) and OVLO OVP BEHAVIOR pulse duty cycle low (<5%) to limit the thermal stress OFF OFF OFF NON-LATCH on the load transient circuit. The load step current can be monitored with a BNC connected to J5 (25mV/A). RUN MODE TRACK/SS V Select F OUT SET ON CCM SS 3.3V V > 3.0V OUT 6. (Optional) To test the advanced input and load pro- tections, put the corresponding jumper in the ON 2. With power off, connect the input power supply, load position. For DC1543B, the thresholds for different and meters as shown in Figure1. Preset the load to 0A input and output protections are set as shown below: and V supply to be 0V. IN INPUT OVLO 36V 3. Turn on the power at the input. Increase V to 12V IN NON-LATCH INPUT OVP 32V (Do not apply more than the rated maximum voltage INPUT UVLO 8V for Rising Edge of 38V to the board or the part may be damaged). 7V for Falling Edge The output voltage should be regulated and deliver the OVER-TEMP LATCH 145C selected output voltage 1.5%. BEHAVIOR NON-LATCH 145C: Cease Regulation 4. Vary the input voltage from 4.5V to 38V and adjust 135C: Resume Regulation the load current from 0A to 10A. Observe the output voltage regulation, ripple voltage, efficiency, and other Rev. 0 2