USB-C Fast Charging Controller•Maxim Integrated / Analog Devices

Maxim MAX77705 Fast Charging IC

Verified Hardware Cross-Reference • MAX77705 (WLCSP-81 (0.40 mm bump pitch))

Technician Direct Cross-Reference

100% Verified

The Maxim MAX77705 charging controller manages 25W/45W charging in Samsung flagships. Compatible donor boards include Galaxy S20, S20+, S20 Ultra, Note 20, Note 20 Ultra, S20 FE, and Tab S7.

Compatible Donor Phones

4 models

These 4 devices share the exact same hardware component and can serve as scrap donors.

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Samsung S20+samsung

Samsung S20+

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Samsung Note 20 Ultrasamsung

Samsung Note 20 Ultra

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Samsung Galaxy S20 FEsamsung

Samsung Galaxy S20 FE

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Samsung Z Flipsamsung

Samsung Z Flip

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Engineering & Micro-Soldering Specs

Pinout dimensions, voltage rails, package footprint, and stencil requirements.

Primary RoleUSB-PD 3.0 PPS fast charging, battery charger, and buck switcher
Nominal VoltageInput 5V - 13.5V (VBUS up to 28V tolerance)
Package FootprintWLCSP-81 (0.40 mm bump pitch)
Dimensions3.9 mm × 3.9 mm × 0.5 mm
Pin / Ball Pitch0.40 mm bump pitch, 81 solder spheres
BGA StencilDedicated MAX77705 Laser Stencil

Workshop Harvesting & Rework SOP

Professional micro-soldering instructions for safe removal and installation.

01

Thermal & Short-Circuit Triage

Inject 1.0V to 1.8V on the primary VDD / VPH_PWR rail using a regulated DC bench supply. Inspect for hot spots using infrared thermal imaging or rosin atomization before removal.

02

Safe Desoldering & Thermal Shielding

Protect adjacent CPU and NAND flash ICs with polyimide Kapton tape and pure copper shielding. Apply RMA paste flux and heat with hot air at 345°C - 365°C with 40% airflow until balls liquefy.

03

Pad Cleanup & BGA Reballing

Clean scrap solder with copper desoldering braid at 320°C. Secure the chip in a Dedicated MAX77705 Laser Stencil, spread Sn63/Pb37 (183°C) leaded solder paste, and heat gradually at 280°C.

04

Alignment & Post-Install Verification

Align orientation pin 1 dot marker to the motherboard silkscreen. Reflow at 350°C until the chip naturally self-centers. Measure diode mode drops across surrounding inductors to confirm no shorts.

In-Depth Repair Guide

Maxim MAX77705 Fast Charging IC: Complete Technical Breakdown & Donor Guide

Read our technical teardown analysis for this component.

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Frequently Asked Questions