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
What are the key features of MCP9805-BE/ST?
- 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
What is MCP9805-BE/ST used for?
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.
What are the specifications of MCP9805-BE/ST?
| 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 |
Where can I find the MCP9805-BE/ST datasheet?
MCP9805-BE/ST Datasheet DownloadOfficial datasheet from Microchip
What are equivalent replacements for MCP9805-BE/ST?
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.
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| Qty. | Unit Price | Ext. Price |
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| 1+ | $1.0500 | $1.05 |
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