Analog Devices Inc./Maxim Integrated

The LT8306 is a micropower isolated flyback controller in a 6-lead ThinSOT™package. By sampling the isolated output voltage directly from the primary-side flyback waveform, the part requires no third winding or opto-isolator for regulation. The output voltage is programmed with a single external resistor. Internal compensation and soft-start further reduce external component count. Boundary mode operation provides a small magnetic solution with excellent load regulation. Low ripple burst mode operation maintains high efficiency at light load while minimizing the output voltage ripple. The LT8306 drives a low side N-channel power MOSFET with 8V gate drive.The LT8306 has a wide input voltage range of 4.5V to 60V. The high level of integration and the use of boundary and low ripple burst modes result in a simple-to-use, low component count, and high efficiency application solution for isolated power delivery.APPLICATIONSIsolated Telecom, Automotive, Industrial, Medical Power SuppliesIsolated Auxiliary/Housekeeping Power Supplies

The LT8311 is used on the secondary side of a forward converter to provide synchronous MOSFET control and output voltage feedback through an opto-coupler. The LT8311’s unique preactive mode allows control of the secondary-side MOSFETs without requiring a traditional pulse transformer for primary- to secondary-side communication. In preactive mode, the output inductor current operates in discontinuous conduction mode (DCM) at light load. If forced continuous mode (FCM) operation is desired at light load, the LT8311 can, alternatively, be used in SYNC mode, where a pulse transformer is required to send synchronous control signals from the primary-side IC to the LT8311.The LT8311 offers a full featured opto-coupler controller, incorporating a 1.5% reference, a transconductance error amplifier and a 10mA opto-driver. Power good monitoring and output soft-start/overshoot control are also included. The LT8311 is available in a 16-lead FE package with pins removed for high voltage spacing requirements.ApplicationsOffline and HV Car Battery Isolated Power Supplies48V Isolated Power SuppliesIndustrial, Automotive and Military Systems

The LT8315 is a high voltage flyback converter with integrated 630V/300mA switch. No opto-isolator is needed for regulation. The device samples the output voltage from the isolated flyback waveform appearing across a third winding on the transformer. Quasi-resonant boundary mode operation improves load regulation, reduces transformer size, and maintains high efficiency.At start-up, the LT8315 charges its INTVCCcapacitor via a current source attached to the DRAIN pin. During normal operation, the current source turns off and the device draws its power from a third winding on the transformer.The LT8315 operates from a wide range of input supply voltages and can deliver up to 15W of power. It is available in a thermally enhanced 20-pin TSSOP package with four pins removed for high-voltage spacing.ApplicationsIsolated Telecom, Automotive, Industrial, Medical Power SuppliesIsolated Off Line Housekeeping Power SuppliesElectric Vehicles and Battery Stacks