Overview
The LM77CIMX-3/NOPB is a digital temperature sensor and thermal window comparator produced by Texas Instruments. This component is designed to provide accurate temperature measurements and is particularly useful in various thermal management and protection applications. It features an I2C serial bus interface, making it compatible with the Advanced Configuration and Power Interface (ACPI) specification, which is commonly used in personal computers and other electronic devices.
Key Specifications
| Parameter | Value |
|---|---|
| Supply Voltage | 3.0V to 5.5V |
| Supply Current - Operating | 250 μA (typ), 500 μA (max) |
| Supply Current - Shutdown | 5 μA (typ), 10 μA (max) |
| Temperature Accuracy | −10°C to 65°C: ±1.5°C (max) −25°C to 100°C: ±2.0°C (max) −55°C to 125°C: ±3.0°C (max) |
| Resolution | 9-bit + sign |
| Temperature Conversion Time | 70 ms to 125 ms |
| Package Type | SOIC-8 |
| Operating Temperature Range | −55°C to 125°C |
Key Features
- Serial Bus Interface conforming to the ACPI specification
- 9-bit + sign digital output with a full-scale reading over 128°C
- Separate open-drain outputs for Interrupt (INT) and Critical Temperature Alarm (T_CRIT_A)
- Programmable upper and lower temperature limits and critical temperature limit
- Shutdown mode to minimize power consumption
- Support for up to 4 LM77s connected to a single bus
- User-programmable hysterisis and fault queue to minimize false tripping
- Two pins (A0, A1) for address selection
Applications
- System Thermal Management
- Personal Computers
- Office Electronics
- Electronic Test Equipment
- Automotive
- HVAC (Heating, Ventilation, and Air Conditioning) systems
Q & A
- What is the operating temperature range of the LM77CIMX-3/NOPB?
The operating temperature range is −55°C to 125°C. - What is the supply voltage range for the LM77CIMX-3/NOPB?
The supply voltage range is 3.0V to 5.5V. - How many LM77 devices can be connected to a single bus?
Up to 4 LM77 devices can be connected to a single bus. - What is the resolution of the temperature measurement?
The resolution is 9-bit + sign, with a least significant bit (LSB) equal to 0.5°C. - What are the typical applications of the LM77CIMX-3/NOPB?
Typical applications include system thermal management, personal computers, office electronics, electronic test equipment, automotive, and HVAC systems. - How does the LM77CIMX-3/NOPB handle critical temperature alarms?
The LM77CIMX-3/NOPB has a separate Critical Temperature Alarm (T_CRIT_A) output that becomes active when the temperature exceeds a programmable critical limit. - What is the default temperature setting for the LM77CIMX-3/NOPB?
The default thresholds are 2°C THYST, 10°C TLOW, 64°C THIGH, and 80°C T_CRIT. - Can the LM77CIMX-3/NOPB be powered down to minimize power consumption?
Yes, the LM77CIMX-3/NOPB has a shutdown mode to minimize power consumption. - How does the LM77CIMX-3/NOPB handle address selection?
The LM77CIMX-3/NOPB has two pins (A0, A1) available for address selection. - What is the temperature conversion time for the LM77CIMX-3/NOPB?
The temperature conversion time is between 70 ms and 125 ms.
