74HC373 Octal Latch IC
Technical overview of the 74HC373 octal latch IC, commonly used for external ROM interfacing in Honda ECU hardware.
The 74HC373 is an octal transparent latch featuring 3-state outputs. In Honda ECU applications, it is primarily utilized to latch 8 bits of data when interfacing with external ROM chips.
Functional Overview
The device acts as a buffer between the MCU and the external memory. By latching the address or data bus, it ensures stable signal propagation during the read/write cycles required for custom tuning and data logging.
Important
Ensure the latch enable (LE) pin is correctly synchronized with the MCU's ALE (Address Latch Enable) signal to prevent data corruption during memory access.
Pinout Configuration
| Pin | Function | Description |
|---|---|---|
| 1 | OE | Output Enable (Active Low) |
| 2-9 | Q0-Q7 | Data Outputs |
| 10 | GND | Ground |
| 11 | LE | Latch Enable |
| 12-19 | D0-D7 | Data Inputs |
| 20 | VCC | Supply Voltage (+5V) |
Application in ECU Hardware
When modifying an ECU for external ROM support, the 74HC373 is typically integrated into the address decoding logic.
OE
- GND
LE
- MCU ALE
No matching connections.
Tip
When replacing a faulty 74HC373, use a high-quality IC socket to facilitate future troubleshooting or chip swapping.
Technical Specifications
- Logic Family: High-speed CMOS (HC)
- Voltage Range: 2.0V to 6.0V
- Output Drive: Standard 3-state output
- Propagation Delay: Dependent on VCC; typically < 20ns at 5V