LTC4308 - Low Voltage, Level Shifting Hot Swappable 2-Wire Bus Buffer with Stuck Bus Recovery
Features
- Optimized for Low Voltage Systems Down to 0.9V
- Bidirectional Buffer with Stuck Bus Recovery
- -200mV Offset In-Out/+300mV Offset Out-In
- 30ms Stuck Bus Timeout
- Compatible with Non-Compliant VOL I2C Devices
- Prevents SDA and SCL Corruption During Live Board Insertion and Removal from Backplane
- ±6kV Human Body Model (HBM) ESD Protection
- Isolates Input SDA and SCL Lines from Output
- Compatible with I2C, I2C Fast Mode and SMBus
- READY Open-Drain Output
- 1V Precharge on SDAOUT and SCLOUT Lines
- Small 8-Lead (3mm × 3mm × 0.75mm) DFN and 8-Lead MSOP Packages
Typical Application
Description
The LTC4308 hot swappable, 2-wire bus buffer allows I/O card insertion into a live backplane without corruption of the data and clock busses. The LTC4308 provides bidirectional buffering, keeping the backplane and card capacitances isolated. Negative offset from output to input allows communication between output bus devices with high VOL and devices on the low voltage input side, where bus supplies can be as low as 0.9V. If SDAOUT or SCLOUT are low for 30ms, the LTC4308 will automatically break the Input-Output connection. At this time the LTC4308 automatically generates up to 16 clock pulses on SCLOUT in an attempt to free the bus. A connection will resume if the stuck bus is cleared.During insertion, the SDAOUT and SCLOUT lines are pre-charged to 1V to minimize bus disturbances. When driven high, the ENABLE input allows the LTC4308 to connect after a stop bit or bus idle condition. Driving ENABLE low breaks the connection between SDAIN and SDAOUT, SCLIN and SCLOUT. READY is an open-drain output which indicates that the backplane and card sides are connected.
Packaging
CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.
For complete and up to date package information and drawings, please refer to our packaging page
| Part Number | Package | Code | Temp | Package Drawing |
RoHS |
|---|---|---|---|---|---|
| LTC4308CDD#PBF | 3x3 DFN-8 | DD | C | 05-08-1698 | Yes |
| LTC4308CDD#TRPBF | 3x3 DFN-8 | DD | C | 05-08-1698 | Yes |
| LTC4308CMS8#PBF | MS-8 | MS8 | C | 05-08-1660 | Yes |
| LTC4308CMS8#TRPBF | MS-8 | MS8 | C | 05-08-1660 | Yes |
| LTC4308IDD#PBF | 3x3 DFN-8 | DD | I | 05-08-1698 | Yes |
| LTC4308IDD#TRPBF | 3x3 DFN-8 | DD | I | 05-08-1698 | Yes |
| LTC4308IMS8#PBF | MS-8 | MS8 | I | 05-08-1660 | Yes |
| LTC4308IMS8#TRPBF | MS-8 | MS8 | I | 05-08-1660 | Yes |
Order Info
- Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
- Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
- Please refer to our general ordering information or the product datasheet for more details
Package Variations and Pricing
| Part Number | Package | Temp | Price (1-99) |
Price (1k)* |
RoHS | |
|---|---|---|---|---|---|---|
| LTC4308CDD#PBF | 3x3 DFN-8 | C | $3.07 | $2.15 | Yes | |
| LTC4308CDD#TRPBF | 3x3 DFN-8 | C | $2.21 | Yes | ||
| LTC4308CMS8#PBF | MS-8 | C | $3.07 | $2.15 | Yes | |
| LTC4308CMS8#TRPBF | MS-8 | C | $2.21 | Yes | ||
| LTC4308IDD#PBF | 3x3 DFN-8 | I | $3.68 | $2.58 | Yes | |
| LTC4308IDD#TRPBF | 3x3 DFN-8 | I | $2.64 | Yes | ||
| LTC4308IMS8#PBF | MS-8 | I | $3.68 | $2.58 | Yes | |
| LTC4308IMS8#TRPBF | MS-8 | I | $2.64 | Yes | ||
| Buy Now • Request Samples | ||||||
Demo Boards
Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.Click here to view our complete list of demo boards
Applications
- Live Board Insertion
- Servers
- Capacitance Buffer/Bus Extender
- RAID Systems
- ATCA
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Design Tools
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- And More!
Technical Support
- For immediate technical assistance, contact your local sales office or distributor or call 1-800-4-LINEAR (US customers only) or 408-432-1900.
- For less urgent requests, please complete our Technical Support Request Form. Please allow 2-3 business days for reply.
