Features: ` Converts Thermistor Temperature to Digital Data
` Low Average Thermistor Current Minimizes Self-Heating Errors
` Low Supply Current, 21A (typ) Including 10k Thermistor Current
` Internal Voltage Reference Isolates Thermistor from Power-Supply Noise
` 10-Bit Resolution
` Accommodates Any Thermistor Temperature Range
` Output Data Scaled for Direct Temperature Readings from 0°C to +50°C
` Simple SPI-Compatible Interface
` Small, 8-Pin MAX PackageApplicationHVAC
Medical Devices
Battery Packs/Chargers
Home AppliancesPinout
SpecificationsSupply Voltage (VCC to GND) ..............................-0.3V to +6V
SO, SCK, CS, R-, R+ to GND ....................-0.3V to (VCC + 0.3V)
R+ Current ...................................................................±20mA
R- Current ......................................................................±1mA
SCK, CS, SO Current .........................................-1mA to +50mA
ESD Protection (Human Body Model) ...........................±2000V
Continuous Power Dissipation (TA = +70°C)
8-Pin MAX (derate 4.1mW/°C above +70°C)......... 328mW
Operating Temperature Range
(TMIN to TMAX) ...........................................-55°C to +125°C
Storage Temperature Range ........................-65°C to +150°C
Junction Temperature ..................................................+150°C
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
DescriptionThe MAX6682 converts an external thermistor's temperature-dependent resistance directly into digital form.The thermistor and an external fixed resistor form a voltage-divider that is driven by the MAX6682's internal voltage reference. The MAX6682 measures the voltage across the external resistor and produces a 10-bit + sign output code dependent on that voltage.
The MAX6682 does not linearize the highly nonlinear transfer function of a typical negative temperature coefficient (NTC) thermistor, but it does provide linear output data over limited temperature ranges when used with an external resistor of the correct value. Over the 0° to +50°C temperature range, the MAX6682 produces output data that is scaled to 8LSBs/°C (for 0.125°C resolution),provided that the correct thermistor and external resistor values are used. Other temperature ranges can be easily accommodated, but do not necessarily yield data scaled to an even number of LSBs per degree.
The 3-wire SPI™-compatible interface can be readily connected to a variety of microcontrollers.
The MAX6682 is a read-only device, simplifying use in systems where only temperature data is required.Power-management circuitry reduces the average thermistor current, minimizing self-heating. Between conversions,supply current is reduced to 21A (typ). The internal voltage reference is shut down between measurements.
The MAX6682 is available in a small, 8-pin MAX package and is specified over the -55°C to +125°C temperature range.
MAX6682 Data Sheet
