Specifications
Note that operating Tibbit #43-1 in extreme conditions (i.e., close to the absolute boundaries) for extended periods can lead to component aging, performance degradation, and premature failure.
| Table 11 — Absolute Maximum Ratings | |
|
Supply voltage |
–10V to +5.5V |
|
CH1 to CH4 relative to GND |
–12V to +12V |
|
Differential voltage: CH1-to-CH2 and CH3-to-CH4 |
–24V to +24V |
|
TX, RX, RTS, –MCLR lines |
–0.3V to +5.5V |
|
Operating temperature |
–40°C to +85°C |
|
ESD protection on analog I/O lines* |
2.5kV |
* While the analog lines have electrostatic discharge (ESD) protection capability (embedded in the ADC IC), Tibbo recommends that ESD precautions still be taken to avoid any performance degradation or permanent damage to the device. This specification has not been tested by Tibbo. The value is reproduced from the AD7323 ADC datasheet.
| Table 12 — Nominal Electrical Characteristics | |
|
Input supply voltage |
4.5VDC to 5.5VDC |
|
Current consumption |
20mA to 25mA |
|
CH1 to CH4 relative to GND |
–10V to +10V |
|
Differential voltage: CH1-to-CH2 and CH3-to-CH4 (without GND connection) |
–20V to +20V |
|
Input resistance: CH1 through CH4 relative to GND |
>10MΩ |
|
Input resistance: CH1-to-CH2 or CH3-to-CH4 (differential) |
|
|
TX, RX, RTS, –MCLR lines, LOW state |
0V to 0.8V |
|
TX, RX, RTS, –MCLR lines, HIGH state |
2V to 5V |
| Table 13 — Functional Characteristics (Verified @ 25°C) | |
|
Sampling mode |
4 x single-ended channels OR 2 x differential channels |
|
Single-ended input voltage range |
–10V to +10V |
|
Differential input voltage range |
–20V to +20V |
|
Common-mode input voltage (differential mode)(1) |
–2VDC to +2VDC |
|
Nominal output resolution |
12-bit + 1-bit sign |
|
Effective output resolution(2) |
10-bit + 1-bit sign |
|
Non-linearity @ full-scale and effective output resolution |
< ±0.1% |
|
Offset @ full-scale and effective output resolution |
< ±10mV |
|
Maximum sampling rate, one single-ended or differential channel enabled, ASCII or hexadecimal data output format(3) |
500 samples per second |
|
Maximum sampling rate, one single-ended channel enabled, binary data output format(3) |
1,000 samples per second |
|
Maximum sampling rate, two single-ended or differential channels enabled, ASCII or hexadecimal data output format(3) |
200 sampling groups/second |
|
Maximum sampling rate, two single-ended or differential channels enabled, binary data output format(3) |
400 sampling groups/second |
|
Maximum sampling rate, four single-ended channels enabled, ASCII or hexadecimal data output format(3) |
100 sampling groups/second |
|
Maximum sampling rate, four single-ended channels enabled, binary data output format(3) |
200 sampling groups/second |
|
Maximum delay between the sampling of two sequential channels in a group, binary data output format |
~30 microseconds |
|
Input resistance: CH1 to CH4 relative to GND |
>10MΩ |
|
Input resistance: CH1 to CH2 (differential) |
>10MΩ |
|
Input resistance: CH3 to CH4 (differential) |
>10MΩ |
- If the common-mode DC voltage in differential mode exceeds the specified values, the input voltage range (swing) cannot be as high as the differential input voltage range. Based on the application, exceeding the specified common-mode input voltage range will likely affect the input swing. In general, the maximum input swing will be narrowed by the amount of voltage in excess of the common-mode input voltage range to maintain the nominal input voltage thresholds.
For example, if a sensor with a common-mode input voltage of 5VDC — exceeding the specified range by 3VDC — is connected to Tibbit #43-1 in differential mode, the input swing will be reduced to –20V to +17V. For more information, refer to the "True-differential mode" section of the datasheet for the AD7323. - During the quality control stage of production, Tibbit #43-1 is calibrated for linearity and resolution.
- Tibbo recommends that the binary output data format be used for high sampling rates. See Data Output Formats for more information.
| Table 14 — Temperature Effect (Compared with Characteristics @ 25°C) | |
|
Maximum added error @ -40°C |
±5mV @ Vin = full range |
|
Maximum added error @ +85°C |
±5mV @ Vin = 9.9V |
| Table 15 — Serial Interface Characteristics | |
|
Interface type |
UART |
|
Flow control* |
Standard RTS (no CTS) |
|
Mode |
Full duplex |
|
Baudrate |
230,400 (fixed) |
|
Data bits |
8 bits |
|
Stop bits |
1 bit |
|
Parity |
No |
* All Tibbo Project PCBs support flow control for UART communications with only an RTS line. If you use Tibbit #43-1 on another platform whose CPU does not support flow control, the Tibbit's RTS line must be set to LOW to allow data flow out of the Tibbit permanently. Note that in such a case, the host CPU's buffer must be big enough to accommodate the desired sampling rate to avoid data loss or a buffer overflow.