ZHCSQR7A October 2023 – June 2024 ISOTMP35
PRODUCTION DATA
To design with ISOTMP35, use the parameters listed in Table 7-4. Most CMOS-based ADCs have a sampled data comparator input structure. When the ADC charges the sampling capacitor, the capacitor requires instantaneous charge from the output of the analog temperature sensor, such as the ISOTMP35. Therefore, the output impedance of the temperature sensor can affect ADC performance. In most cases, adding an external capacitor mitigates design challenges. The ISOTMP35 is specified and characterized with a 1000pF maximum capacitive load (CLOAD). The CLOAD is a sum of the CFILTER, CMUX and CSAMPLE. TI recommends maximizing the CFILTER value while allowing for the maximum specified ADC input capacitance (CMUX + CSAMPLE) to limit the total CLOAD at 1000pF. In most cases, a 680pF CFILTER provides a reasonable allowance for ADC input capacitance to minimize ADC sampling error and reduce noise coupling. An optional series resistor (RFILTER) and CFILTER provides additional low-pass filtering to reject system level noise. TI recommends placing RFILTER and CFILTER as close to the ADC input as possible for optimal performance.
PARAMETER | VALUE |
---|---|
Supply voltage, VDD | 2.3V to 5.5V |
Decoupling capacitor between VDD and GND | 0.1µF |