CS5503-BP

Features 

lMonolithic CMOS ADC with Filtering 

- 6-Pole, Low-Pass Gaussian Filter 

l Up to 4 kHz Output Word Rates 

- On Chip Self-Calibration Circuitry 

- Linearity Error: ±0.0003% 

- Differential Nonlinearity: CS5501: 16-Bit No Missing Codes (DNL ±1/8 LSB) CS5503: 20-Bit No Missing Codes 

l System Calibration Capability 

l Flexible Serial Communications Port 

- µC-Compatible Formats 

- 3-State Data and Clock Outputs 

- UART Format (CS5501 only) 

l Pin-Selectable Unipolar/Bipolar Ranges 

l Low Power Consumption: 25 mW 

- 10 µW Sleep Mode for Portable Applications 

l Evaluation Boards Available

Description 

The CS5501 and CS5503 are low-cost CMOS A/D converters ideal for measuring low-frequency signals representing physical, chemical, and biological processes. They utilize charge-balance techniques to achieve 16-bit (CS5501) and 20-bit (CS5503) performance with up to 4 kHz word rates at very low cost. 

The converters continuously sample at a rate set by the user in the form of either a CMOS clock or a crystal. Onchip digital filtering processes the data and updates the output register at up to a 4 kHz rate. The converters’ lowpass, 6-pole Gaussian response filter is designed to allow corner frequency settings from 0.1 Hz to 10 Hz in the CS5501 and 0.5 Hz to 10 Hz in the CS5503. Thus, each converter rejects 50 Hz and 60 Hz line frequencies as well as any noise at spurious frequencies. 

The CS5501 and CS5503 include on-chip self-calibration circuitry which can be initiated at any time or temperature to insure offset and full-scale errors of typically less than 1/2 LSB for the CS5501 and less than 4 LSB for the CS5503. The devices can also be applied in system calibration schemes to null offset and gain errors in the input channel. 

Each device’s serial port offers two general purpose modes of operation for direct interface to shift registers or synchronous serial ports of industry-standard microcontrollers. In addition, the CS5501’s serial port offers a third, UART-compatible mode of asynchronous communication.