LTC3807EUDC LGSG Buck Regulator Positive Output Step-Down DC-DC Controller

LTC3807EUDC LGSG Buck Regulator | Low-IQ Synchronous Step-Down Controller for Antminer L3+ Hashboard Repair

The LTC3807EUDC (marking 714 LGSG) is a low-IQ synchronous step-down DC-DC controller in a 20-WFQFN exposed-pad package, used on the Antminer L3+ hashboard to drive an external MOSFET pair into a buck topology. Wide 4V to 38V input supply range + 0.8V precision reference + up to 99% duty cycle covers the full range of hashboard voltage conversion requirements from a single controller IC.

Key features for hashboard control duty: 50kHz to 900kHz programmable switching frequency, TRACK/SS pin for output voltage ramping, power-good output for system status monitoring, tracking input for multi-rail sequencing, current limit + soft start + frequency control + enable. The controller drives external MOSFETs (not integrated) — sized to whatever output current the hashboard rail needs, up to the FET's capability.

When to Replace the LTC3807EUDC

• Antminer L3+ hashboard rail dead — controller not driving the external MOSFET pair.
• Hashboard boots but rail drops under load — controller entering current-limit or losing regulation.
• Power-good output stuck low on the controller — internal fault or output out of spec.
• Visible damage on the 20-WFQFN package after a downstream MOSFET failure or transient event.
• Adjacent external MOSFETs also failed — replace MOSFETs + controller together to avoid repeat failure.

LTC3807EUDC LGSG Specifications

FAQ — LTC3807EUDC Buck Controller

Q: Controller vs converter — what's the difference?
A: A converter has integrated MOSFETs (small current capability, drop-in simplicity). A controller drives external MOSFETs (higher current capability, more BOM complexity). The LTC3807EUDC is a controller — when it dies, also inspect the external MOSFET pair it was driving. They often go together.

Q: How do I confirm the controller is the failed part?
A: Scope the high-side and low-side gate-drive outputs. Healthy controller produces clean PWM at the programmed frequency (50–900kHz range). Dead controller produces no drive, asymmetric drive, or shoot-through. Also check the power-good output — should be high once VOUT is in regulation.

Q: 20-WFQFN rework profile?
A: WFQFN with exposed pad — bottom-side preheat 130–150°C, top-side hot air 320°C with flux paste. The exposed pad carries thermal load and must reflow to the board's copper. After reflow, verify all 20 pins via continuity test + scope-probe the gate-drive outputs under low-power conditions before re-energising the full hashboard.

Q: Bulk pricing for L3+ repair benches?
A: Yes — email contact@lys-sz.com for tube-quantity LTC3807EUDC pricing and matched external-MOSFET kits.

Related products

• TPS61161DRVR BZR LED Driver / Boost (Antminer L3+)
• L3+ / S9 Boost Module 14V (6R8 RT8537)
• Antminer L3+ U73 Step-Down Power Module
• SPX5205M5 Linear Voltage Regulator (Antminer S9 / L3)

Antminer L3+ repair benches stocking LTC3807EUDC buck controllers by the tube? Email contact@lys-sz.com for bulk pricing. Worldwide shipping from our Shenzhen warehouse.