LM94 - Hardware Monitor with PI Loop Fan Control | Texas Instruments
MPN: LM94 β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.5 | $8.50 |
| 10 | $7.65 | $76.50 |
| 100 | $6.8 | $680.00 |
| 500 | $6.12 | $3,060.00 |
| 1,000 | $5.5 | $5,500.00 |
Drop-in alternatives for LM94 β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
LM96194
β Drop-Inπ Reference alternative (not in catalog)
ADM1276
β Drop-Inπ Reference alternative (not in catalog)
ADM1275
β Drop-Inπ Reference alternative (not in catalog)
ADM1278
β Drop-Inπ Reference alternative (not in catalog)
ADM1272
β Drop-Inπ Reference alternative (not in catalog)
LM94 Maximum Ratings & Electrical Characteristics
| Interface | SMBus 2.0 |
| ADC Type | Sigma-Delta |
| Remote Temperature Channels | 4 |
| Local Temperature Channels | 1 |
| Voltage Monitor Channels | 16 |
| Fan Control | PI Loop |
| TruTherm Technology | Yes |
| Supply Voltage | 3.3 V |
| Package | 44-pin TSSOP |
| Operating Temperature Range | [DATA_NEEDED: operating temperature range] |
| SMBus Address | Programmable via pins |
| Alert Output | Yes |
| RoHS Status | Compliant |
| Mounting Type | Surface Mount |
| Number of Pins | 44 |
LM94 Pin Configuration
| Pin 1 | VCC β Power supply (3.3V) |
| Pin 2 | GND β Ground |
| Pin 3 | SDA β SMBus data line |
| Pin 4 | SCL β SMBus clock line |
| Pin 5 | ALERT β Alert output (active low) |
| Pin 6 | D1+ β Remote diode 1 positive |
| Pin 7 | D1- β Remote diode 1 negative |
| Pin 8 | D2+ β Remote diode 2 positive |
| Pin 9 | D2- β Remote diode 2 negative |
| Pin 10 | D3+ β Remote diode 3 positive |
| Pin 11 | D3- β Remote diode 3 negative |
| Pin 12 | D4+ β Remote diode 4 positive |
| Pin 13 | D4- β Remote diode 4 negative |
Safe Operating Area (SOA) & Thermal Characteristics
No official SOA curve available for this digital IC. Always operate within absolute maximum ratings specified in the datasheet. Ensure adequate cooling and derate as needed.
Typical Applications
LM94 is suitable for 6 applications: Server Motherboards, Networking Equipment, Storage Systems, Telecom Infrastructure, Industrial PCs, Gaming and High-Performance Computing.
Server Motherboards
The LM94 is ideal for server motherboards where monitoring multiple temperatures and voltages is critical. Its four remote diode channels can monitor CPU, GPU, and other hot spots, while the 16 voltage monitors cover all major power rails. The PI loop fan control automatically adjusts fan speeds to maintain optimal thermal conditions, reducing acoustic noise and power consumption. With its SMBus interface, the LM94 integrates seamlessly with baseboard management controllers (BMCs) for remote system management. This ensures reliable operation in data centers where uptime is paramount.
Recommended
Networking Equipment
In networking switches and routers, the LM94 provides essential thermal and voltage monitoring to ensure reliable operation in high-density environments. The device's ability to monitor four remote diodes allows tracking of multiple ASICs or optical modules. The 16 voltage monitors cover the various supply rails used in networking gear. The PI loop fan control helps manage cooling efficiently, which is critical for maintaining performance and longevity. The SMBus interface enables integration with network management systems for proactive monitoring and alerts.
Recommended
Storage Systems
The LM94 is well-suited for storage systems, including RAID controllers and NAS devices, where monitoring drive temperatures and power supplies is essential. Its four remote diode channels can monitor multiple drives or controllers, while the 16 voltage monitors ensure stable power delivery. The PI loop fan control adjusts cooling based on temperature, preventing overheating and extending drive lifespan. The SMBus interface allows integration with storage management software for real-time health monitoring. This helps prevent data loss due to thermal or power issues.
Recommended
Telecom Infrastructure
In telecom base stations and central office equipment, the LM94 provides robust monitoring of temperatures and voltages to ensure continuous operation. The device's multiple remote diode channels can monitor power amplifiers and other heat-generating components. The 16 voltage monitors cover the various supply rails used in telecom systems. The PI loop fan control helps manage cooling in outdoor or confined environments. The SMBus interface enables remote monitoring and control, which is essential for unmanned sites. This ensures high reliability and reduces maintenance costs.
Recommended
Industrial PCs
The LM94 is suitable for industrial PCs used in factory automation and process control, where reliable operation in harsh environments is required. Its four remote diode channels can monitor CPU, GPU, and other critical components. The 16 voltage monitors ensure stable power delivery to sensitive electronics. The PI loop fan control helps maintain optimal operating temperatures, preventing thermal shutdowns. The SMBus interface allows integration with industrial control systems for real-time monitoring. This enhances system reliability and reduces downtime in manufacturing environments.
Recommended
Gaming and High-Performance Computing
In gaming PCs and high-performance computing (HPC) systems, the LM94 provides comprehensive monitoring of temperatures and voltages to ensure peak performance and stability. Its four remote diode channels can monitor CPU, GPU, and memory modules. The 16 voltage monitors cover all critical power rails. The PI loop fan control adjusts fan speeds dynamically, balancing cooling and noise. The SMBus interface allows enthusiasts to monitor system health via software. This helps prevent overheating and ensures consistent performance during intense workloads.
Recommended
Recommended Products Summary
Engineering reference data for LM94 β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LM96194 | ADM1276 | ADM1275 |
|---|---|---|---|---|
| Package | 44-pin TSSOP | 44-pin TSSOP | 44-pin TSSOP | 44-pin TSSOP |
| Brand | Texas Instruments | Texas Instruments | Analog Devices | Analog Devices |
| Remote Temperature Channels | 4 | 4 | 4 | 4 |
| Voltage Monitor Channels | 16 | 16 | 16 | 16 |
| Fan Control | PI Loop | PI Loop | Yes | Yes |
| Interface | SMBus 2.0 | SMBus 2.0 | SMBus | SMBus |
| TruTherm Technology | Yes | Yes | No | No |
| Supply Voltage | 3.3V | 3.3V | 3.3V | 3.3V |
Key Differentiators
- TruTherm technology for accurate sub-micron processor diode measurements (vs ADM1276)
- PI loop fan control for efficient cooling (vs ADM1275)
- 16 voltage monitor channels (vs ADM1272)
Design Notes
For accurate remote diode temperature measurements, route the D+ and D- traces as a differential pair with proper shielding. Keep traces short and away from noisy signals. Use a ground plane around the diode connections to minimize noise pickup. Refer to the LM94 datasheet for recommended layout guidelines.
The LM94 operates from a 3.3V supply. Ensure adequate decoupling with a 0.1uF ceramic capacitor placed close to the VCC pin. For noisy environments, add a 10uF bulk capacitor. The SMBus lines should have pull-up resistors to 3.3V as per SMBus specifications.
When using the PI loop fan control, ensure the fan tachometer input is properly connected and configured. Incorrect fan type or polarity can cause erratic behavior. Also, verify the SMBus address is set correctly to avoid conflicts with other devices on the bus.
Compliance Information
RoHS compliance indicated in datasheet. Other compliance details not specified in provided data.
