LTM4644 pin-to-pin replacement — HG4644 / HG4644T drop-in guide

If your design uses the Analog Devices LTM4644 or LTM4644T uModule regulator, HGCHIPS supplies a PIN2PIN compatible replacement from stock: HG4644 for the 6.9 mm part and HG4644T for the 5.4 mm low-profile part. No layout change, no configuration-resistor change.

What actually differs — and what does not

Per the original manufacturer's public datasheet, LTM4644 and LTM4644T are electrically the same part: 4 V to 14 V input, 0.6 V to 5.5 V adjustable output, 16 A in single-output mode and 4 A per channel in quad-output mode, on the same 10 x 16 mm land pattern. The published difference is package height — 6.9 mm versus 5.4 mm. That is why we publish two replacement part numbers instead of one: height is a mechanical constraint, not a marketing detail, and getting it wrong fails assembly rather than the datasheet.

Everything else — ball-out, footprint, feedback resistor network, soft-start, frequency selection and sequencing behaviour — is designed to stay as-is. That is the point of a PIN2PIN part: the qualification effort goes into verification, not into redesign.

Qualification checklist for a uModule second source

1. Height and clearance. Measure your keep-out above the module, then choose 6.9 mm (HG4644) or 5.4 mm (HG4644T).
2. First-article comparison. Output voltage accuracy, ripple, load-step transient response and start-up sequencing at your actual Vin, load and temperature.
3. Thermal rise. Run at worst-case ambient and full load on your own board, not on a test jig.
4. EMI/EMC spot check. Switching edges differ between suppliers even at the same switching frequency — confirm the existing input filter is still sufficient.
5. Traceability paperwork. Lot test reports and the cross-reference sheet go into your component-engineering file so the second source is auditable.

Start with a small batch: MOQ is 10 pcs and stock ships within 48 h from Shenzhen. The datasheet, mechanical drawing, cross-reference sheet and lot test reports can go out with the samples.

Full cross-reference: LTM46xx

ADI uModule POL DC-DC (LTM46xx) — 21 part numbers

Frequently asked questions about LTM4644 replacement

Is there a pin-to-pin replacement for the LTM4644?

Yes. HG4644 is a PIN2PIN compatible replacement for Analog Devices LTM4644, and HG4644T covers the LTM4644T low-profile variant. Same 10 x 16 mm footprint, same ball-out and the same electrical envelope: Vin 4 V to 14 V, Vout 0.6 V to 5.5 V, 16 A in single-output mode and 4 A per channel in quad-output mode.

What is the difference between the LTM4644 and the LTM4644T, and does one replacement cover both?

The only difference published by the original manufacturer is package height: LTM4644 is 6.9 mm tall and LTM4644T is 5.4 mm, with identical electrical specifications. Because height is a mechanical constraint we list two part numbers - HG4644 (6.9 mm) and HG4644T (5.4 mm). Pick the height your mechanical stack-up needs.

Do I need to change my PCB layout or my configuration resistors?

The land pattern and ball-out are the same, so no layout change is expected, and the Vout-setting resistor network, soft-start and frequency-select components stay as designed. We still recommend a first-article comparison on your own board: output ripple, load transient, thermal rise and start-up sequencing, exactly as you would for any second source.

What is the minimum order quantity and can I get samples?

MOQ is 10 pcs and stock ships within 48 hours from Shenzhen. For qualification we can supply a small batch together with the datasheet, mechanical drawing, cross-reference sheet and lot test reports.

Which other uModule parts can you replace?

The current cross-reference covers 21 LTM46xx and 8 LTM80xx part numbers, listed in the tables on this page, plus the LTM3605 stock line. If your part number is not listed, send it and we will check it against our portfolio and supply channel rather than proposing something that does not fit.

Are these parts re-marked or refurbished?

No. HGCHIPS parts are independently engineered replacements supplied with traceability and lot test reports. They are not original-brand product and they are not re-marked original material.