The Industry's First Thermostat Output IC with a Temperature Switching Function

ROHM has developed thermostat output temperature sensor ICs that electronically detect the temperature in current and next generation electronic products requiring temperature control and circuits that generate heat, such as power supplies and motor drivers. Normally, a thermistor or comparator is used for temperature detection. However, these require precision reference voltages and complicated circuitry. ROHM’s new ICs integrate a high precision reference voltage source, comparator, and constant current circuit with a temperature detection element into a single chip, simplifying circuit design and reducing costs. Two series are offered, the BDEXXX0G (open drain, active low) that can switch between 3 levels, centered around the detection temperature (+5ºC or −5ºC), and the BDFXXX0G series (open drain, active low), featuring 9-interval switching, also centered at the detection temperature (+2.5ºC, +5ºC, +7.5ºC, +10ºC, −2.5ºC, −5ºC, −7.5ºC, or −10ºC). This eliminates the need to stock multiple temperature ICs- required when the detection temperature changes due to circuit modification or target operating environment- reducing costs while increasing design flexibility.
Samples of 90ºC and 120ºC detector units in the BDEXXX0G series (sample price: 3.5$) and 100ºC detector models in the BDFXXX0G series (sample price: 4.3$) are available, with mass production scheduled for December.

· Main Features of the BDEXXX0G Series and BDFXXX0G Series

1. Wide detection temperature range
   BDEXXX0G Series: 15 types, from −20ºC to +120ºC, in increments of 10ºC
   BDFXXX0G Series: 8 types, from −20ºC to +120ºC, in increments of 20ºC
2. Detection temperature switching function based on control pins
   BDEXXX0G Series: switching among three levels, +5ºC or −5ºC, centered around the detection temperature
   BDFXXX0G Series: switching among nine levels, +2.5ºC, +5ºC, +7.5ºC, +10ºC, −2.5ºC, −5ºC, −7.5ºC, or −10ºC, centered around the detection temperature
3. High temperature detection accuracy: ± 4ºC (± 5ºC for 120ºC detection: BDE1200G, BDF1200G)
4. Low current consumption: 16μA typ.
5. Detection temperature hysteresis: 10ºC typ.
6. Output type: open drain, active low
7. Compact package types
   BDEXXX0G Series: SSOP5 (2.9mm × 2.8mm × 1.25Max.mm)
   BDFXXX0G Series: SSOP6 (2.9mm × 2.8mm × 1.25Max.mm)

New Product Bulletin for Thermostat Output IC with a Temperature Switching Function(PDF:445KB)

· Glossary

• Thermostat
  A function that controls the temperature of a system by turning circuits ON or OFF based on temperature changes. Several types exist (i.e. bimetal, electronic).
• Thermistor
  A temperature-sensitive sensor that uses a semiconductor sintered with a metal oxide such as Mn (manganese), Co (cobalt), Ni (nickel), or Fe (iron), whose electrical resistance changes based on temperature. Some substances decrease resistance as the temperature increases (NTC) while others increase resistance with rising temperature (PTC).
• Reference Voltage Source
  A voltage source used for a comparator output trigger (high precision is necessary).
• Active Low and Active High Output
  The output is “active low” if the thermostat output switches from “H” (power supply voltage) to “L” (ground) when a certain temperature is detected, and “active high” if it switches from “L” to “H”.
• Open Drain and CMOS Output
  This refers to the structure of the output MOS transistor of the thermostat temperature sensor IC. Open drain output has an Nch MOS drain terminal as the output terminal, while the CMOS output type has a two-level upper/lower structure consisting of a Pch MOS and an Nch MOS. Selection is made based on the method of connecting to the circuit or block that receives the signal from the thermostat temperature sensor IC, or on the required load (current) or power supply voltage. Open drain output is often used when the power supply voltage is different from the thermostat output temperature sensor IC and the next stage circuit, or when load (current) is required in the next stage. CMOS output is recommended when the thermostat output temperature sensor IC and the next stage circuit have the same power supply voltage, or when rapid output signal response is needed.

Temperature Sensor ICs