3-state hex inverting buffer# Technical Documentation: HEF40098BF 8-Bit Addressable Latch
Manufacturer: PHILIPS (Nexperia)
Component Type: CMOS 8-Bit Addressable Latch
Series: HEF4000B Family
---
## 1. Application Scenarios (≈45%)
### Typical Use Cases
The HEF40098BF is a monolithic integrated circuit designed as an 8-bit addressable latch with three-state outputs. Its primary function is to store data and selectively output it based on address inputs, making it ideal for applications requiring data routing, temporary storage, and bus interfacing.
Key Operational Modes:
* Data Latching: When the `STROBE` input is high, the data present at the `DATA` input is latched into the bit selected by the 3-bit address (`A0, A1, A2`).
* Output Control: The three-state outputs are enabled (active) when the `OUTPUT ENABLE` (`OE`) input is low. A high on `OE` places all eight outputs (`Q0-Q7`) in a high-impedance (Hi-Z) state, allowing the device to be disconnected from a shared bus.
### Industry Applications
1. Microprocessor/Microcontroller Systems:
* Port Expansion: Used to add extra output ports by latching data from a shared data bus, controlled by address and control signals from the CPU.
* Memory-Mapped I/O: Functions as an interface latch for peripherals (LED displays, relays, sensors) where each latch output is assigned a unique memory address.
* Bus Buffering and Demultiplexing: Isolates the CPU bus from peripheral lines and demultiplexes address/data buses to drive multiple devices.
2. Data Routing and Distribution:
* Signal Routing Switches: Routes a single serial data stream to one of eight parallel output channels based on the address, useful in communication systems and test equipment.
* Display Drivers: Can be used to latch segment data for multi-digit LED or LCD displays, with each digit controlled by a specific address.
3. Industrial Control Systems:
* Actuator Control: Latches control signals to activate solenoids, motors, or indicators in a sequenced or addressed manner.
* Digital Panel/Instrumentation: Manages multiple status indicators or control signals from a limited number of controller pins.
### Practical Advantages and Limitations
Advantages:
* High Noise Immunity: Standard CMOS technology offers high noise margins (typically ~30% of VDD).
* Low Power Consumption: Very low quiescent current (in the µA range), making it suitable for battery-powered devices.
* Wide Supply Voltage Range: Operates from 3V to 15V, providing compatibility with various logic families (e.g., interfacing 5V TTL with level shifting).
* Three-State Outputs: Enable direct connection to bidirectional data buses without contention.
* Simple Addressing: 3-bit address directly selects one of eight latches, simplifying control logic.
Limitations:
* Moderate Speed: Compared to modern high-speed logic (e.g., 74HC series), the HEF4000B family has lower maximum clock frequencies (typically ~10 MHz at 10V VDD). Not suitable for high-speed data paths.
* Output Current: Sink/source current capability is limited (typically ~1 mA at 5V). Requires buffer transistors (e.g., ULN2003) to drive high-current loads like relays or motors directly.
* ESD Sensitivity: As a CMOS device, it is susceptible to Electrostatic Discharge (ESD). Requires careful handling during assembly
