DIFFERENTIAL 4 CHANNLE ANALOG MULTIPLEXER DEMULTIPLEXER# Technical Documentation: HCF4052 Dual 4-Channel Analog Multiplexer/Demultiplexer
Manufacturer : STMicroelectronics
Document Version : 1.0
Last Updated : October 2023
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## 1. Application Scenarios
### 1.1 Typical Use Cases
The HCF4052 is a CMOS-based dual 4-channel analog multiplexer/demultiplexer with digital control inputs. Its primary function is to route analog or digital signals from multiple sources to a single destination (multiplexing) or from a single source to multiple destinations (demultiplexing).
Key operational modes:
- Signal Routing in Test Equipment : Used in automated test systems to switch between multiple sensor inputs or signal sources to a single measurement instrument (e.g., oscilloscope, data acquisition system).
- Audio Signal Switching : In audio mixers or routing systems, it can select between different audio input channels (e.g., microphones, instruments) with minimal signal degradation.
- Data Acquisition Systems (DAQ) : Multiplexes multiple analog sensor outputs (temperature, pressure, voltage) into a single analog-to-digital converter (ADC), reducing system cost and complexity.
- Programmable Gain Amplifiers (PGA) : By switching between different feedback resistors in an op-amp circuit, it enables selectable gain settings under digital control.
### 1.2 Industry Applications
Industrial Automation & Control
- PLC I/O Expansion : Multiplexes analog inputs from various process sensors (4–20 mA, 0–10V) to a controller’s limited ADC channels.
- Motor Control Monitoring : Switches between different motor phase current or voltage sensing points for diagnostics.
Consumer Electronics
- Battery Management Systems (BMS) : Selects individual cell voltages in a battery pack for monitoring and balancing.
- Home Audio/Video Switching : Routes audio/video signals in AV receivers or selector switches.
Telecommunications
- Signal Routing in Modems/Transceivers : Switches between different filter networks or impedance matching circuits based on frequency band or modulation scheme.
Medical Devices
- Patient Monitoring : Multiplexes bio-signals (ECG, EEG) from multiple electrodes to a processing unit.
Automotive
- Sensor Interface Modules : Multiplexes outputs from multiple automotive sensors (e.g., temperature, pressure, position) to an ECU’s ADC.
### 1.3 Practical Advantages and Limitations
Advantages:
- Low Power Consumption : CMOS technology ensures minimal power draw, suitable for battery-operated devices.
- Wide Analog Signal Range : Can handle analog signals from VEE to VDD (typically ±5V with ±5V supplies), accommodating bipolar signals.
- High Off-State Isolation : Typically >50 dB at 1 kHz, minimizing crosstalk between unselected channels.
- Break-Before-Make Switching : Prevents momentary shorting during channel transitions, protecting signal sources.
- Digital Control Compatibility : Standard CMOS/TTL-compatible control inputs (A, B, INH) for easy microcontroller interfacing.
Limitations:
- Limited Bandwidth : -3 dB bandwidth typically <50 MHz, unsuitable for high-frequency RF applications (>100 MHz).
- On-Resistance Variation : RON (typically 125Ω at VDD-VSS=10V) varies with supply voltage and signal level, causing gain errors in precision circuits.
- Charge Injection : During switching, a small amount of charge (typically 10 pC) is injected into the signal path, causing voltage glitches in high-impedance circuits.
- Signal Attenuation : The RON and parasitic capacitance form a low-pass filter, attenuating higher frequency signals.
- Voltage Limitations : Absolute maximum supply voltage (VDD to VSS) is 20V; exceeding
