LM87是TI公司的一款监控和??风扇控制产品，LM87是具有远程二极管温度传感的串行接口系统硬件监控器，本页介绍了LM87的产品说明、应用、特性等，并给出了与LM87相关的TI元器件型号供参考。
LM87 - 具有远程二极管温度传感的串行接口系统硬件监控器 - 监控和??风扇控制 - 其他传感器信号调节器 - TI公司（Texas Instruments，德州仪器）
The LM87 is a highly integrated data acquisition system for hardware monitoring of servers, Personal Computers, or virtually any microprocessor-based system. In a PC, the LM87 can be used to monitor power supply voltages, motherboard and processor temperatures, and fan speeds. Actual values for these inputs can be read at any time. Programmable WATCHDOG limits in the LM87 activate a fully programmable and maskable interrupt system with two outputs (INT# and THERM#).
The LM87 has an on-chip digital output temperature sensor with 8-bit resolution as well as the capability of monitoring 2 external diode temperatures to 8-bit resolution, an 8 channel analog input ADC with 8-bit resolution and an 8-bit DAC. A channel on the ADC measures the supply voltage applied to the LM87, nominally 3.3 V. Two of the ADC inputs can be redirected to a counter that can measure the speed of up to 2 fans. A slow speed ΣΔ ADC architecture allows stable measurement of signals in an extremely noisy environment. The DAC, with a 0 to 2.5 V output voltage range, can be used for fan speed control. Additional inputs are provided for Chassis Intrusion detection circuits, and VID monitor inputs. The VID monitor inputs can also be used as IRQ inputs if VID monitoring is not required. The LM87 has a Serial Bus interface that is compatible with SMBus and I2C.
- Remote diode temperature sensing (2 channels)
- 8 positive voltage inputs with scaling resistors for monitoring +5 V, +12 V, +3.3 V, +2.5 V, Vccp power supplies directly
- 2 inputs selectable for fan speed or voltage monitoring
- 8-bit DAC output for controlling fan speed
- Chassis Intrusion Detector input
- WATCHDOG comparison of all monitored values
- SMBus or I2C Serial Bus interface compatibility
- VID0-VID4 or IRQ0-IRQ4 monitoring inputs
- On chip temperature sensor
Key Specifications
- Voltage Monitoring Error ±2 % (max)
- External Temperature Error ±4 °C (max)
- Internal Temperature Error
- −40 °C to +125 °C ± 3 °C (typ)
- Supply Voltage Range 2.8 to 3.8 V
- Supply Current 0.7 mA (typ)
- ADC and DAC Resolution 8 Bits
- Temperature Resolution 1.0 °C
