Microchip MCP970x Low-Power Linear Active Thermistor IC
Ideal for space-critical and low-cost applications
Microchip features the MCP9700/9700A/9700B and MCP9701/9701A, which is a family of analog temperature sensors that convert temperature to analog voltage. These Linear Active Thermistor Integrated Circuit (IC) feature an accuracy of ±1°C from +20°C to +70°C (MCP9700B), ±2°C from 0°C to +70°C (MCP9700A/9701A) and ±4°C from 0°C to +70°C (MCP9700/9701) while consuming 6 µA (typical) of operating current.
Unlike resistive sensors, e.g., thermistors, the MCP970x Linear Active Thermistor IC by Microchip does not require an additional signal-conditioning circuit. Therefore, the biasing circuit development overhead for thermistor solutions can be avoided by implementing a sensor from these low-cost devices. The Voltage Output pin (VOUT) can be directly connected to the ADC input of a microcontroller.
The MCP9700/9700A/9700B and MCP9701/9701A temperature coefficients are scaled to provide a 1°C/bit resolution for an 8-bit ADC with a reference voltage of 2.5V and 5V, respectively. The MCP9700/9700A/ 9700B output 0.1°C/bit for a 12-bit ADC with 4.096V reference. The MCP9700/9700A/9700B and MCP9701/9701A provide a low-cost solution for applications that require measurement of a relative change of temperature.
When measuring relative change in temperature from +25°C, an accuracy of ±1°C (typical) can be realized from 0°C to +70°C. This accuracy can also be achieved by applying system calibration at +25°C. The MCP9700B can measure temperature with ±1°C from +20°C to +70°C without any system calibration.
In addition, this family of devices is immune to the effects of parasitic capacitance and can drive large capacitive loads. This provides printed circuit board (PCB) layout design flexibility by enabling the device to be remotely located from the microcontroller. Adding some capacitance at the output also helps the output transient response by reducing overshoots or undershoots. However, capacitive load is not required for the stability of sensor output.
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