DC1560A Analog Devices

DEMO MANUAL DC1560A LTM8048 Isolated Module DC/DC Converter with LDO Post Regulator DESCRIPTION Demo circuit 1560A is an isolated flyback Module The two-stage converter provides an isolated flyback output DC/DC converter with LDO post regulator featuring as well as a low noise LDO output. Figure 2 shows the LTM 8048. The demo circuit is designed for a 6V flyback output noise spectrum on V and Figure 3 shows the OUT1 output and a 5V post regulator output from a 4.5V to 30V output noise spectrum on V . OUT2 input. The typical current capability of the 6V flyback output The LTM8048 data sheet gives complete description of the varies with input voltage from about 110mA at V = 4.5V IN device, operation and application information. The data to about 370mA at V = 30V. Figure 1 shows the typical IN sheet must be read in conjunction with this demo manual maximum output current on V when V is not OUT1 OUT2 prior to working on or modifying demo circuit 1560A. loaded. V is the LDO post regulator from V . The OUT2 OUT1 Design files for this circuit board are available at current capability of V is limited by either the current OUT2 DEMO MANUAL DC1560A DESCRIPTION 500 0 0 450 20 20 400 40 40 350 300 60 60 250 80 80 200 150 100 100 100 120 120 50 0 140 140 4 68 10 12 14 16 18 20 22 24 26 28 30 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 V (V) FREQUENCY (MHz) FREQUENCY (MHz) IN DC1560A F01 DC1560A F03 DC1560A F02 Figure 3. V Output Noise Figure 1. V Typical Maximum Figure 2. V Output Noise OUT2 OUT1 OUT1 Spectrum with I at 100mA and Output Current vs V When V is Spectrum with I at 100mA and OUT2 IN OUT2 OUT2 V at 12V (V Has no Extra Load) not Loaded V at 12V (V Has no Extra Load) IN OUT1 IN OUT1 PERFORMANCE SUMMARY (T = 25C) A PARAMETER CONDITION VALUE Minimum Input Voltage 4.5V Maximum Input Voltage 30V Output Voltage V V = 7V to 30V 6.0V 5% OUT1 IN Output Voltage V V = 7V to 30V 5.0V 3% OUT2 IN Voltage Ripple V V = 12V, I = 0mA, I = 100mA <20mV OUT1 IN OUT2 OUT2 Voltage Ripple V V = 12V, I = 0mA, I = 100mA <10mV OUT2 IN OUT2 OUT2 QUICK START PROCEDURE Demo circuit 1560A is easy to set up to evaluate the per- 2. Turn on the power at the input. formance of the LTM8048. Refer to Figure 4 for proper NOTE. Make sure that the input voltage does not exceed measurement equipment setup and follow the procedure 30V. below: 3. Check for the proper output voltages. (For V , check OUT1 NOTE. When measuring the input or output voltage the voltage between V and V . For V , check OUT1 OUT OUT2 ripple, care must be taken to avoid a long ground lead the voltage between V and V .) OUT2 OUT on the oscilloscope probe. Measure the input or output NOTE. If there is no output, temporarily disconnect the voltage ripple by touching the probe tip directly across load to make sure that the load is not set too high. the V or V and GND terminals. See Figure 5 for IN OUT proper scope probe technique. 4. Once the proper output voltages are established, adjust the load within the operating range and observe the 1. With power off, connect the input power supply to V IN output voltage regulation, ripple voltage, efficiency and and GND. other parameters. dc1560af 2 OUTPUT CURRENT (mA) INTENSITY (dBm) INTENSITY (dBm)