BM1366 ASIC Chip

Overview

The BM1366 is a SHA-256 mining ASIC manufactured by Bitmain, used primarily in the Antminer S19 XP series. It represents a significant efficiency improvement over the BM1398 used in the original S19 line.

Specifications

Pin Configuration

The BM1366 uses a BGA (Ball Grid Array) package. Key signal groups:

Power Pins

• VDD — Core power supply (0.28V nominal)
• VDDIO — I/O power supply (1.8V)
• VSS — Ground

Communication Pins

• CI — Clock Input (from previous chip or controller)
• CO — Clock Output (to next chip)
• RI — Receive Input (data from previous chip)
• RO — Receive Output (data to next chip)
• BO — Break Out signal (fault indication)

PLL Pins

• XCLK — External clock reference input

// PLL frequency register configuration for BM1366
// Target: 500 MHz core clock
#define BM1366_PLL_FREQ_500M  0x00F0286401
#define BM1366_PLL_FREQ_600M  0x00F0306401
#define BM1366_PLL_FREQ_700M  0x00F0386401

Common Failure Modes

1. Dead Chip (No Response)

• Chip does not respond to enumeration
• Often caused by electrical overstress or manufacturing defect
• Diagnose by testing BO signal and checking voltage at chip VDD pads

2. Low Performance

• Chip responds but produces fewer hashes than expected
• May indicate partial core failure
• Check PLL lock status and core voltage stability

3. Thermal Failure

• Chip overheats and triggers thermal shutdown
• Check thermal paste application and heatsink contact
• See Cooling & Thermal Management

Replacement Procedure

Replacing a BM1366 requires BGA rework equipment:

For detailed BGA rework techniques, see the BGA Rework Guide.

Found In These Miners

• Antminer S19 XP — 140 TH/s, 134 chips per board
• Antminer S19 XP Hydro — liquid-cooled variant

Compare With

• BM1368 — Next generation, used in S21
• BM1398 — Previous generation, used in S19/S19 Pro
• BM1362 — Used in S19j Pro

Further Reading

• ASIC Chip Architecture
• Voltage Domains & Regulators
• Clock Distribution & PLL