JAJSRF7 October 2023 ISOTMP35-Q1
ADVANCE INFORMATION
To design with ISOTMP35-Q1, use the parameters listed in Table 8-4. 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-Q1. Therefore, the output impedance of the temperature sensor can affect ADC performance. In most cases, adding an external capacitor mitigates design challenges. The ISOTMP35-Q1 is specified and characterized with a 1000-pF 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 1000 pF. In most cases, a 680-pF 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 | 2.3 V to 5.5 V |
Decoupling capacitor between VDD and GND | 0.1 µF |