Flyback controller for isolated supplies — the MP temperature grade
The LT3798MPMSE#PBF is an isolated flyback switching controller from Analog Devices, built for applications that demand galvanic isolation between primary and secondary sides of the power supply. The controller drives an external MOSFET — no internal switch — so the power stage current rating and Rds(on) are set by the designer's choice of transistor, not by the IC. That is the full military-screened band — the same silicon, but tested and guaranteed across the wider thermal envelope. For a flyback controller that must start and regulate at -55°C and survive 150°C junction in a sealed enclosure or under-hood environment, this is the grade to specify.
Switching frequency and supply — tuning the EMI and efficiency trade
The switching frequency spans 500 Hz to 150 kHz, set by an external timing resistor. A 500 Hz bottom end is unusually low for a modern controller — useful for very high step-down ratios where the minimum on-time limits the switching frequency, or for synchronizing to a sub-1 kHz external clock. The 150 kHz upper end keeps switching losses manageable in a compact transformer design while staying below the AM broadcast band for conducted EMI compliance. Supply voltage (Vcc/Vdd) is 10 V to 38 V. The 38 V maximum covers 24 V industrial rails with margin for transients, but for a 48 V telecom input a front-end regulator or a different controller with a higher Vcc max would be needed.
Package and board integration — 16-MSOP-EP exposed pad
Housed in a 16-lead TFSOP with exposed pad, 3.00 mm width, the supplier device package is listed as 16-MSOP-EP — the same mechanical outline. The 0.118-inch (3.00 mm) body width is a fine-pitch MSOP footprint — standard for this class of controller — and the Tube packaging means the parts arrive in anti-static tubes, not tape-and-reel, which affects pick-and-place feeder setup for volume production.
The part remains in the current portfolio for new and existing designs. ROHS3 compliant (no exemptions), which clears it for global shipment under the EU RoHS directive without needing a certificate of exemption.