DEMO MANUAL DC2194A LTM4642IY 20V , DUAL 4A or SINGLE 8A IN DC/DC MODULE REGULATOR DESCRIPTION Demonstration circuit of DC2194A features the preferred for noise sensitive applications. The mode pin LTM 4642IY, the wide input voltage, high efficiency and can also be used to sync the switching frequency to an power density, dual 4A or single 8A DC/DC step-down external clock. Programmable switching frequency range Module regulator. The step-down regulator operates is from 600kHz to 1400kHz with a 30% synchronization from an input voltage range of 4.5V to 20V (or 2.5V min. capture range. Constant on time, valley current mode with 5V external bias voltage at CPWR) and provides an control architecture and integrated internal control loop adjustable output voltage range from 0.6V to 5V at 4A load compensation allow very fast transient response to line current per channel. The part is capable of operating in and load changes while maintaining loop stability. dual phase single output, delivers up to 8A load current It is recommended to read the data sheet and demo with interleaved two phases at 180 degrees. Differential manual of LTM4642 prior using or making any changes output voltage sensing is available on Channel 1 for ap- to DC2194A. plications requiring more accurate output load regulation. Design files for this circuit board are available at A user-selectable mode input is provided to allow users to DEMO MANUAL DC2194A PERFORMANCE SUMMARY Specifications are at T =25C A PARAMETER CONDITIONS VALUE Dual Phase Dual Output Configuration (Default) Input Voltage Range 4.5V to 20V Input Voltage Range 2.5V to 20V (with External CPWR Bias Supply) Default Output Voltage V =4.5V to 20V 1.8V 1.5% IN V I =0A to 4A 1.2V 1.5% OUT1 LOAD V f =800kHz OUT2 SW Default Switching Frequency Programmed Frequency with an External Resistor 800kHz 10% from FREQ Pin to SGND Maximum Continuous Output Current I per Channel V =4.5V to 20V 4A OUT IN (Dual Phase Dual Outputs) f =800kHz SW Output Voltage Ripples V =12V V , =27mV (Figure 8a) IN OUT1 P-P (Peak-to-Peak) f =800kHz V , =17mV (Figure 8b) SW OUT2 P-P V V =1.8V at I =4A OUT1,P-P OUT1 OUT1 V V =1.2V at I =4A OUT2,P-P OUT2 OUT2 (Dual Phase Dual Outputs) C = 1x150F+1x22F per Channel OUT Dynamic Load Transient Response V =12V V , =86mV (Figure 7a) IN OUT1 P-P V f =800kHz V , =67mV (Figure 7b) OUT1,P-P SW OUT2 P-P V Mode=CCM OUT2,P-P (Dual Phase Dual Outputs) V =1.8V, I =2A to 4A OUT1 OUT STEP V =1.2V, I =2A to 4A OUT2 OUT STEP C =1x150F+1x22F per Channel OUT Efficiency V =12V Channel 1: 87.8% (Figure 4) IN (Dual Phase Dual Outputs) f =800kHz Channel 2: 84.2% (Figure 4) SW V =1.8V at I =4A OUT1 OUT1 V =1.2V at I =4A OUT2 OUT2 Thermal Performance V =12V 57.2C Peak Temperature IN (Dual Phase Dual Outputs) f =800kHz (Figure11a) SW V =1.8V at I =4A OUT1 OUT1 V =1.2V at I =4A OUT2 OUT2 T =25C, No Forced Airflow/Heat Sink A dc2194afa 2