2SB772 SMD Medium Power Transistor SOT-89 for Avalon PSU repair

2SB772 SMD Medium-Power PNP Transistor | SOT-89 Replacement for Avalon Power Supply PSU Repair

The 2SB772 is a PNP medium-power bipolar transistor in SOT-89 SMD package, used on Avalon power supply units for primary-side housekeeping and gate-drive support functions. Direct complementary pair to the D882 (NPN) — Avalon PSU primary circuits often use both in matched pairs for push-pull driver stages and class-AB output sections.

Headline specs for PSU primary duty: 30V VCEO / 40V VCBO breakdown, 3.0A continuous collector current, 5.0V VEBO, with low saturation voltage, excellent hFE linearity, and high hFE across the operating range. Low-speed switching characteristic suits the audio-band housekeeping circuits where saturation losses matter more than switching frequency.

When to Replace the 2SB772

• Avalon PSU housekeeping rail dead — 2SB772 driver pair shorted or open.
• Asymmetric output waveforms on the push-pull stage — one of the matched pair (2SB772 / D882) degraded.
• Visible damage on the SOT-89 package — burnt or cracked after a primary-side fault event.
• Excessive base current draw measured during scope diagnostic — hFE collapsed, transistor degraded.
• Adjacent matched-pair NPN (D882) also failed — replace both as a matched set.

2SB772 PNP Transistor Specifications

FAQ — 2SB772 PNP Transistor

Q: How do I confirm the 2SB772 is the dead part?
A: Power off. DMM diode-test mode between base + emitter, and base + collector. Healthy PNP reads ~0.6V from emitter to base, ~0.6V from collector to base (positive lead on E or C, negative on B). Shorted reads 0Ω. Open reads OL. Test the matched D882 (NPN) at the same time — they usually fail together.

Q: Replace in matched pairs with the D882?
A: Yes — when the Avalon PSU uses a push-pull or class-AB stage with the 2SB772 + D882 pair, replace both even if only one tests bad. The matched pair design assumes balanced hFE and VBE; replacing one and leaving the aged partner unbalances the stage and stresses the new device unevenly.

Q: SOT-89 rework profile?
A: Standard SOT-89 hot-air rework. Bottom-side preheat 100°C, top-side hot air 320°C with flux paste. The metal tab on the SOT-89 conducts heat to the board copper — give the joint extra dwell time vs a leadless package, but don't overheat adjacent passives.

Q: Bulk pricing for Avalon PSU repair benches?
A: Yes — email contact@lys-sz.com for reel-quantity 2SB772 pricing and matched D882 pair kits.

Related products

• 2SB772T H72P PNP Transistor (low saturation)
• Avalon PSU 3300W (A1066 / A1166 / A1246)
• 2N7002 60V/115mA N-MOSFET (Antminer hashboard)
• BCX56 / BCX56-16 NPN Transistor (Whatsminer P21 PSU)

Avalon PSU repair benches stocking 2SB772 transistors by the reel? Email contact@lys-sz.com for bulk pricing. Worldwide shipping from our Shenzhen warehouse.