16/24-Bit A/D Converters with Ultra-Low-Noise PGIA
The CS5531/32/33/34 family of highly integrated, Delta Sigma analog-to-digital (A/D) converters use charge-balance techniques to achieve 16-bit (CS5531/33) and 24-bit (CS5532/34) performance. The A/D converters are optimized for measuring low-level unipolar or bipolar signals in weigh scale, process control, scientific and medical applications. To accommodate these applications, the A/D converters come as 2-channel (CS5531/32) or 4-channel (CS5533/34) devices and include a very low noise, chopper-stabilized instrumentation amplifier (6 nV/√Hz at 0.1 Hz) with selectable gains of 1x, 2x, 4x, 8x, 16x, 32x and 64x. These A/D converters also include a fourth-order Delta Sigma modulator followed by a digital filter, which provides 20 selectable-output word rates of 6.25, 7.5, 12.5, 15, 25, 30, 50, 60, 100, 120, 200, 240, 400, 480, 800, 960, 1600, 1920, 3200 and 3840 samples per second (SPS) (MCLK = 4.9152 MHz). To communicate with a microcontroller, the converters include a simple, 3-wire serial interface (SPI and Microwire compatible) with a Schmitt Trigger input (SCLK). High dynamic range, programmable output rates, and flexible power supply options make these A/D converters ideal solutions for weigh scale and process control applications.
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Features
- Chopper-stabilized PGIA (1x to 64x)
- 6 nV/√Hz at 0.1 Hz (No 1/f noise) at 64x
- 500 pA input current with gains >1
- Delta Sigma A/D converter
- Linearity error: 0.0007% FS
- Noise-free resolution: up to 23 bits
- 2- or 4-channel differential mux
- Scalable input span via calibration
- ± 5 mV to differential ± 2.5 V
- Scalable VREF input: up to analog supply
- Simple 3-wire serial interface
- SPI™ and Microwire™ compatible
- Schmitt Trigger on serial clock (SCLK)
- Selectable word rates: 6.25 to 3,840 samples per second (SPS)
- Selectable 50 Hz or 60 Hz rejection
- Power supply configurations
- VA+ = +5 V; VA- = 0 V; VD+ = +3 V to +5 V
- VA+ = +2.5 V; VA- = -2.5 V; VD+ = +3 V to +5 V
- VA+ = +3 V; VA- = -3 V; VD+ = +3 V
- Package: 20/24-pin SSOP; lead-free assembly
Parametric Specifications
| Resolution (bits) | 16 (CS5531) 24 (CS5532) 16 (CS5533) 24 (CS5534) |
| Throughput (Sps) | 6.25-3840 |
| Integral Linearity (%FS) | 0.0015 (CS5531) 0.0007 (CS5532) 0.0015 (CS5533) 0.0007 (CS5534) |
| Differential Linearity (±LSB) | NMC |
| Channels | 2 (CS5531) 2 (CS5532) 4 (CS5533) 4 (CS5534) |
| Power Consumption (mW) | 35 |
| Package | 20 SSOP (CS5531) 20 SSOP (CS5532) 24 SSOP (CS5533) 24 SSOP (CS5534) |
