Detailed Description Hardware, Input Filtering

MAX1402 Evaluation Kit/Evaluation System

Evaluate: MAX1400/MAX1402

For simplicity, the EV kit software assumes that all three transfer functions are configured alike.

Detailed Description

________________________of Hardware

U1, the MAX1402, is a multichannel, high-resolution A/D converter (refer to the MAX1402 data sheet). U2, the MAX6025, is a 2.5V reference (refer to the MAX6025 data sheet). Y1 contains a ceramic resonator and its load capacitors. R1–R6 together with C3–C8 form anti-aliasing input filters. R8 and C11 filter the digi- tal power supply. The analog supply comes through fil- ter R7/C10.

Input Filtering

The EV kit has an RC filter on each input with a time constant of approximately 0.01µs = 10ns (R = 100Ω, C = 100pF). When scanning between channels, the RC filter’s settling time may increase the acquisition time required for full accuracy.

Evaluating the MAX1400

The MAX1400 can be evaluated by shorting across jumpers JU6 and JU7. The MAX1400 is exactly like the

MAX1402, except that the function of pins 5, 6, 7, and 8 is changed. Instead of the OUT1/OUT2 outputs and DS0/DS1 inputs, these pins are used to provide access to the analog signal between the multiplexer and the A/D converter. Tables 2 and 3 list the jumper functions and default settings. Refer to the MAX1400 data sheet for detailed information.

Measuring Supply Current

Supply current can be estimated by measuring the volt- age across a series resistor. On the EV kit board, the MAX1402 draws all of its analog and digital power through R8, which is 10Ω. In addition, all analog supply current flows through R7, which is also 10Ω.

Troubleshooting

Problem: unacceptable amounts of noise in the signal.

Collect a sample of 1024 measurements at a 60Hz data rate. Observe whether the problem is caused by 60Hz noise.

Any AC-powered equipment connected to the analog signal ground can inject noise. Try replacing AC-pow- ered DVMs with battery-powered DVMs.

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MAX1402 specifications

The Maxim MAX1402 is a highly integrated, low-power 12-bit analog-to-digital converter (ADC) that boasts high performance and versatility, making it ideal for a range of applications including industrial control, portable instrumentation, and medical devices. This component incorporates advanced technology aimed at providing accurate and efficient signal processing.

One of the primary features of the MAX1402 is its high resolution of 12 bits, which allows it to effectively convert analog signals into digital data with a level of detail suitable for precision measurements. The device operates at a sampling rate of up to 1 MSPS (million samples per second), allowing it to capture rapid changes in input signals, making it particularly adept for applications requiring real-time data acquisition.

Another notable characteristic is its low power consumption. With a typical operating current of only 500 µA, the MAX1402 is well-suited for battery-operated devices, where energy efficiency is paramount. The low power feature, combined with the ability to run off a single supply voltage, enhances the device's adaptability in various circuit designs.

The MAX1402 features an onboard sample-and-hold circuit, which facilitates effective signal stability during the conversion process. This is crucial in preventing distortion from high-frequency signals and helps in achieving precise measurement results even in noisy environments.

The converter supports a differential input configuration, which improves common-mode rejection and enhances the overall performance in industrial applications where noise and interference are common. Additionally, the MAX1402 includes an internal reference voltage source, simplifying system design by eliminating the need for external components.

The device is also equipped with a serial interface, which allows for straightforward integration with microcontrollers and other digital systems. This feature streamlines the process of data transmission, enabling seamless communication and control within various systems.

With its compact design and robust performance, the MAX1402 addresses the need for accurate, low-power ADCs in modern electronic applications. Its combination of features, such as 12-bit resolution, 1 MSPS sampling rate, low power consumption, and integrated functionality, positions it as a reliable choice for engineers and designers seeking to enhance their measurement and control systems.