Linear Technology LTM8058 Manuals

1 dc1988af DEMO MANUAL DC1988A Description LTM8058 Isolated μModule DC/DC Converter with LDO Post Regulator Demonstration circuit 1988A is a 2kV AC (3kVDC) isolated flyback μModule® DC/DC converter with LDO post regulator featuring the LTM®8058. The demo circuit is designed for a 6V flyback output and a 5V post regulator output from a 4.5V to 30V input. The current capability of the 6V fly- back output varies with input voltage from about 100mA at 4.5VIN to about 320mA at 30VIN. Figure 1 shows the typical maximum output current on VOUT1 when VOUT2 is not loaded. VOUT2 is the LDO post regulator from VOUT1. The current capability of VOUT2 is limited by either the cur- rent capability of VOUT1 minus VOUT1 loading or the 300mA current limit on the LDO post regulator itself. R1 provides the necessary minimum load current to keep the VOUT1 in regulation throughout the entire input voltage range. Please see the typical performance characteristic curves L, LT, LTC, LTM, µModule, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Performance Summary Board Photo in the LTM8058 data sheet to determine the minimum load current for other input/output configurations. The two-stage converter provides an isolated flyback output as well as a low noise LDO output. Figure 2 shows the output noise spectrum on VOUT1 and Figure 3 shows the output noise spectrum on VOUT2. The LTM8058 data sheet gives a complete description of the device, operation and application information. The data sheet must be read in conjunction with this quick start guide for demo circuit 1988A. Design files for this circuit board are available at http://www.linear.com/demo/DC1988A Specifications are at TA = 25°C PARAMETER CONDITIONS VALUE Minimum Input Voltage 4.5V Maximum Input Voltage 30V Output Voltage VOUT1 VIN = 7V to 30V 6V ±5% Output Voltage VOUT2 VIN = 7V to 30V 5.0V ±3% Voltage Ripple VOUT1 VIN = 12V, IOUT2 = 0mA, IOUT2 = 100mA 10mV Voltage Ripple VOUT2 VIN = 12V, IOUT2 = 0mA, IOUT2 = 100mA 5mV