Precision, 16-Channel/Dual 8-Channel, Low-Voltage, CMOS Analog Multiplexers# Technical Documentation: MAX396EWI Precision, Low-Power, 8-Channel/Dual 4-Channel CMOS Analog Multiplexer
Manufacturer : Maxim Integrated (now part of Analog Devices Inc.)
Document Revision : 1.0
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## 1. Application Scenarios
### 1.1 Typical Use Cases
The MAX396EWI is a monolithic, CMOS analog multiplexer designed for precision signal routing in low-power systems. Its primary function is to connect one of multiple analog input signals to a common output under digital control.
Key Use Cases Include:
* Data Acquisition Systems (DAQS): The device serves as a front-end multiplexer for analog-to-digital converters (ADCs), sequentially sampling multiple sensor inputs (e.g., temperature, pressure, voltage) with a single ADC. This significantly reduces system cost and board space.
* Automated Test Equipment (ATE): Used to route various test signals (stimuli and responses) to and from a device under test (DUT), enabling automated switching between test points for validation and characterization.
* Communication Systems: Employed in signal path switching for modem interfaces, audio routing, and low-frequency RF signal selection where low on-resistance and charge injection are critical.
* Battery-Powered/Portable Instruments: Its low power consumption (typical supply current < 1µA) and wide single-supply voltage range (+4.5V to +30V) or dual-supply (±4.5V to ±20V) operation make it ideal for handheld multimeters, data loggers, and medical monitoring devices.
* Process Control Systems: Multiplexes signals from various transmitters (4-20mA loops, thermocouples) to a central processing unit for monitoring and control.
### 1.2 Industry Applications
* Industrial Automation: PLC I/O modules, sensor interface boards, and motor control feedback systems.
* Medical Electronics: Patient monitoring equipment for routing bio-potential signals (ECG, EEG) and diagnostic sensor arrays.
* Telecommunications: Channel selection in baseband units and switching in backup line cards.
* Automotive: Non-safety-critical sensor multiplexing in infotainment and climate control systems (subject to appropriate environmental qualification).
* Aerospace & Defense: Low-power signal routing in avionics testers and ground support equipment.
### 1.3 Practical Advantages and Limitations
Advantages:
* High Precision: Low on-resistance (100Ω max) and excellent on-resistance matching (4Ω max) minimize signal attenuation and channel-to-channel errors.
* Low Power Consumption: CMOS construction ensures quiescent current is typically below 1µA, ideal for battery-operated systems.
* Rail-to-Rail Signal Handling: The analog signal range extends to the supply rails, maximizing dynamic range in single-supply applications.
* Fault Protection: Inputs are protected against overvoltage faults from -40V to +40V, even when the device is unpowered, enhancing system robustness.
* Flexible Configuration: The "EWI" package (28-pin Wide SOIC) houses two independent 4-channel multiplexers, which can be used separately or combined to form a single 8-channel multiplexer, offering design flexibility.
Limitations:
* Bandwidth Limitation: As a CMOS switch, its bandwidth is suitable for DC to medium-frequency signals (transition times in the hundreds of nanoseconds). It is not intended for high-frequency RF or video switching above a few MHz.
* Charge Injection: A small amount of charge is injected onto the signal path during switching, which can cause transient voltage spikes. This is critical in sample-and-hold and high-impedance applications.
* On-Resistance Variation: The
