MCP9805-BE/ST Microchip Integrated Circuit (Small Outline Packages) In Stock
Microchip MCP9805-BE/ST is a JC42.4-compliant I2C digital temperature sensor with ±3 °C accuracy, programmable alert thresholds, and 12-bit resolution in a TSSOP-8 package. It operates from 3.0 V to 3.6 V for JEDEC DDR memory thermal monitoring. Available with worldwide shipping.
- Manufacturer
- Microchip
- Package
- Small Outline Packages
- Pin Count
- 8
- Lifecycle
- ACTIVE
- Datasheet
- MCP9805-BE/ST Datasheet PDF
- Category
- Integrated Circuit
- Price
- From $0.7120(MOQ 1)
- Temp Range
- -20.0°C to 125.0°C
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
Key Features
- JC42.4-compliant I2C temperature sensor with ±3 °C maximum accuracy across -40 °C to +125 °C and configurable ALERT output for over-temperature protection in DDR memory modules
- 12-bit ADC resolution delivers 0.0625 °C per LSB step, enabling fine-grained thermal monitoring in server and storage rack thermal management systems
- Tiny TSSOP-8 package measuring 4.4 mm × 3 mm × 0.9 mm with 3.0 V to 3.6 V supply, fitting directly on DDR SO-DIMM and UDIMM module edge areas
Applications
The MCP9805-BE/ST is designed for JEDEC JC42.4-compliant temperature sensing on DDR2, DDR3, and DDR4 memory modules where over-temperature throttling and thermal shutdown must be handled autonomously. Its programmable upper, lower, and critical alert thresholds allow the memory controller to reduce read/write frequency before thermal damage occurs. The device also suits general-purpose embedded thermal monitoring in routers, switches, and industrial compute boards where I2C-accessible temperature data is needed alongside other sensor types.
Specifications
| Pbfree Code | Yes |
| Manufacturer Package Code | TSSOP-8 |
| Reach Compliance Code | Compliant |
| Factory Lead Time | 6Weeks |
| YTEOL | 9 |
| Accuracy-Max (Cel) | 3Cel |
| Body Breadth | 3mm |
| Body Height | 0.9mm |
| Body Length or Diameter | 4.4mm |
| Housing | PLASTIC |
| JESD-609 Code | e3 |
| Mounting Feature | SURFACE MOUNT |
| Number of Bits | 11 |
| Operating Current-Max | 0.2mA |
| Output Interface Type | 2-WIRE INTERFACE |
| Package Body Material | PLASTIC/EPOXY |
| Package Equivalence Code | TSSOP8,.25 |
| Package Shape/Style | RECTANGULAR |
| Sensors/Transducers Type | TEMPERATURE SENSOR,SWITCH/DIGITAL OUTPUT,SERIAL |
| Supply Voltage-Max | 3.6V |
| Supply Voltage-Min | 3V |
| Surface Mount | YES |
| Terminal Finish | Matte Tin (Sn) |
| Termination Type | SOLDER |
| Package | Small Outline Packages |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
| Country of Origin | Malaysia, Philippines, Thailand |
Alternate & Equivalent Parts
No known alternates. Submit an RFQ and our team can suggest alternatives.
Frequently Asked Questions
What temperature accuracy and resolution does the MCP9805-BE/ST provide for DDR memory thermal management?
The MCP9805-BE/ST specifies ±3 °C maximum accuracy from -40 °C to +125 °C with 12-bit ADC resolution of 0.0625 °C per LSB. In DDR memory thermal management, this accuracy is sufficient to trigger throttling at the JEDEC-defined 85 °C threshold with confidence that the alarm fires before the module reaches the critical 95 °C damage point.
How are the programmable alert thresholds configured on the MCP9805-BE/ST and what does each threshold do?
The MCP9805-BE/ST provides three I2C-writable threshold registers: T_LOWER, T_UPPER, and T_CRIT. When the temperature exceeds T_UPPER or falls below T_LOWER, the open-drain ALERT pin asserts to notify the host. Exceeding T_CRIT produces a separate critical-level interrupt that maps to the JEDEC TSOD event-driven throttling protocol used in server DIMM sockets.
What supply voltage does the MCP9805-BE/ST require and is it compatible with 3.3 V I2C bus levels?
The MCP9805-BE/ST operates from 3.0 V to 3.6 V, which is within the tolerance band of regulated 3.3 V rails commonly found on DIMM modules and server motherboard I2C management buses. The I2C pins are 3.3 V compatible, so no level shifting is needed when the host SMBus or I2C controller runs at 3.3 V with standard 4.7 kΩ pull-up resistors.
Can the MCP9805-BE/ST be used on standard I2C buses shared with other sensors, and how are address conflicts avoided?
Yes, the MCP9805-BE/ST uses a 3-bit A2/A1/A0 address input allowing up to 8 unique 7-bit I2C addresses on the same bus. In a server chassis with 8 DIMM slots, each slot's MCP9805-BE/ST can be assigned a distinct address, allowing the baseboard management controller to poll all 8 temperature sensors over a single SMBus segment at 100 kHz or 400 kHz.
Related Guides
1206 100 uF MLCC Design Guide for Compact Bulk Decoupling
Design guidance for applying CL31A107MQHNNNE and related 1206 MLCCs in compact bulk decoupling networks.
Jul 3, 2026
0402 10 nF MLCC Design Guide for High-Speed Decoupling
Practical design guidance for using CL05B103KB5NNNC and related 0402 MLCCs in high-speed decoupling networks.
Jul 3, 2026
CL31A107MQHNNNE 1206 100 uF MLCC Selection Guide
How to choose CL31A107MQHNNNE and related 1206 MLCCs for low-voltage bulk capacitance and regulator stability.
Jul 2, 2026
CL05B103KB5NNNC 0402 10 nF X7R MLCC Selection Guide
How to choose CL05B103KB5NNNC and related 0402 MLCCs for bypassing, filtering, voltage derating, and sourcing.
Jul 2, 2026
Why Buy from FindMyChip
About Microchip
Microchip is a leading electronic component manufacturer. FindMyChip sources Microchip ICs directly from authorized China distributors, offering competitive pricing and reliable stock.
| Qty. | Unit Price | Ext. Price |
|---|---|---|
| 1+ | $1.0500 | $1.05 |
| 100+ | $0.8100 | $81.00 |
| 500+ | $0.7900 | $395.00 |
| 1000+ | $0.7800 | $780.00 |
| 5000+ | $0.7140 | $3570.00 |
| 7500+ | $0.7120 | $5340.00 |
In Stock · 24h Response · Worldwide Shipping
Response within 24 hours · Worldwide shipping
“We've been using FindMyChip for 2 years. Pricing is consistently 20-30% below Mouser/DigiKey for volume orders.”