DC1953A Analog Devices

DEMO MANUAL DC1953A LTC3374EUHF 8-Channel Parallelable 1A Buck DC/DC Description Demonstration circuit 1953A is an 8-output power supply The LTC3374 has a default operating frequency of 2MHz featuring the LTC 3374. The LTC3374 has eight synchro- or it can be set between 1MHz and 3MHz using an external nous buck regulators each with an independent V supply. resistor. The LTC3374 also has a SYNC pin which allows IN Up to four buck regulators may be paralleled together to the internal oscillator to synchronize to an external clock create a higher power buck regulator with a single induc- from 1MHz to 3MHz. tor. The input range of the LTC3374 is ideal for single cell Refer to the LTC3374 data sheet for more details on the Li-Ion/Polymer battery applications. electrical and timing specifications. The buck regulators can be enabled via external preci- Design files for this circuit board are available at sion threshold enable pins to allow hardwired power up DEMO MANUAL DC1953A Quick s p D The DC1953A is easy to set up to evaluate the performance Note: Make sure that the input voltages do not exceed 6V. of the LTC3374. Refer to Figure 1 and Figure 2 for proper 6. Set the JP1 jumper, EN1, to the ON position and measurement equipment setup and follow the evaluation observe the VOUT1 regulator turns on and the procedure below. PGOOD ALL LED extinguishes. Note: When measuring the input or output voltage ripple, Note: All regulators not powered or set up as a slave must care must be taken to avoid a long ground lead on the have their EN pins tied to GND to allow the PGOOD ALL oscilloscope probe. Measure the input or output voltage LED to extinguish. ripple by touching the probe tip directly across the VIN or 7. With power off, connect a 0V to 3A load to each VOUT VOUT and GND terminals. See Figure 2 for proper scope and GND with a series ammeter and a voltmeter as probe technique. shown in Figure 1. 1. Set the JP1-JP8 jumpers on the DC1953A board to 8. Slowly increase LOAD1 from 0A to 1A and observe the OFF position. the output voltage. The output ripple may also be 2. Set the MODE jumper, JP9, to the BURST position. observed using an oscilloscope with the probe con- 3. With power off, connect a 0V to 6V, 100mA power nected as shown in Figure 2. supply to VCC and GND with a voltmeter as shown 9. When done evaluating VOUT1, repeat steps 5 through in Figure1. 8 for each regulator. 4. With power off, connect a 0V to 6V, 3A power supply 10. Refer to the LTC3374 data sheet for more details on to each VIN and GND with a series ammeter and a how the LTC3374 operates. voltmeter as shown in Figure 1. A single 0V to 6V, 10A 11. When done, turn off all loads and power supplies. supply can be used instead to supply all VIN inputs simultaneously. 5. Turn on and set the VCC input power supply to 3.3V and turn on and set the VIN1 supply to 5V. dc1953afa 2 ure roce tart