DEMO MANUAL DC2329A LTC7124 17V , Dual 3.5A Synchronous Step-Down Regulator IN with Ultra-Low Quiescent Current Description Demonstration circuit DC2329A features the for noise sensitive applications. The Mode pin can also LTC 7124IUDD: a wide input and output voltage range, be used to synchronize the switching frequency to an high efficiency and power density, dual 3.5A DC/DC step- external clock. Programmable switching frequency ranges down monolithic regulator. The input voltage range of the from 500kHz to 4MHz with a 25% synchronization cap- DC2329A is 3.1V to 17V. The default setting of V is ture range. The constant frequency, peak current mode OUT1 user selectable from 1.2V, 1.5V and 1.8V at 3.5A max. control architecture and integrated internal or optional The default setting of V is user selectable from 2.5V, external control loop compensation network, allows very OUT2 3.3V and 5.0V at 3.5A max. The default switching fre- fast transient response to line and load changes while quency of DC2329A is set at 1MHz typical. Programmable maintaining loopstability. peak current limit of either 2.6A or 5A can be achieved The LTC7124 is available in a thermally enhanced, low by changing the setting of ILIM pin. Selectable internal profile 24-lead 3mmx5mm QFN package. or external loop compensation allows users more options It is recommended to read the data sheet and demo man- to optimize the loop bandwidth and output load transient ual of the LTC7124 prior to using or making any changes response. A user-selectable mode input is provided to to the DC2329A. allow users to trade off ripple noise for light load effi- ciency: pulse skipping mode (PS) or Burst Mode (BM) Design files for this circuit board are available at of operation delivers higher efficiency at light load while DEMO MANUAL DC2329A Quick s tart p D Demonstration circuit DC2329A is easy to set up to GND (E13) to monitor corresponding DC output volt- evaluate the performance of the LTC7124. Please refer ages of Channel 1 and Channel 2. to Figure1 for proper measurement equipment setup and 4. Turn on the power supply at the input. Measure and follow the test procedures below: make sure the input supply voltage is 12V. Place the 1. With power off, connect the input power supply between RUN 1 (JP1) and RUN 2 (JP2) jumpers to the ON V (E1) and GND (E3). V and V are tied together position. The output voltage should be 1.8V 2% for IN1 IN1 IN2 (using zero ohm jumper R1) by default. channel 1 and 2.5V 2% for channel 2. 2. Connect the first load between V (E11) and GND 5. Once the input and output voltages are properly OUT1 (E14) for channel 1, connect the second load between established, adjust the input voltage between 3.1V to V (E12) and GND (E13) for channel 2. Preset all 17V and the load current within the operating range OUT2 the loads to 0A. of 0A to 3.5A max per channel. Observe the output voltage regulation, output voltage ripples, switch 3. Connect the DMMs between the input test points: node waveform, load transient response and other E1 and E3 to monitor input voltage. Connect DMMs parameters. Refer to Figure 2 for proper output voltage between V (E11) and GND (E14), V (E12) and OUT1 OUT2 ripple measurement. LOAD 0A TO 3.5A + + + + + VIN 3.1V TO 17V + + LOAD 0A TO 3.5A DC2329 F01 Figure 1. Proper Measurement Equipment Setup dc2329af 2 ure roce