LTC4308 Low Voltage, Level Shifting Hot Swappable 2-Wire Bus Buffer with Stuck Bus Recovery FEATURES DESCRIPTION n Optimized for Low Voltage Systems Down to 0.9V The LTC 4308 hot swappable, 2-wire bus buffer allows n Bidirectional Buffer with Stuck Bus Recovery I/O card insertion into a live backplane without corrup- n 200mV Offset In-Out/+300mV Offset Out-In tion of the data and clock busses. The LTC4308 provides n 30ms Stuck Bus Timeout bidirectional buffering, keeping the backplane and card 2 n Compatible with Non-Compliant V I C Devices capacitances isolated. Negative offset from output to OL n Prevents SDA and SCL Corruption During Live input allows communication between output bus devices Board Insertion and Removal from Backplane with high V and devices on the low voltage input side, OL n 6kV Human Body Model (HBM) ESD Protection where bus supplies can be as low as 0.9V. If SDAOUT or n Isolates Input SDA and SCL Lines from Output SCLOUT are low for 30ms, the LTC4308 will automati- 2 2 n Compatible with I C, I C Fast Mode and SMBus cally break the Input-Output connection. At this time the n READY Open-Drain Output LTC4308 automatically generates up to 16 clock pulses n 1V Precharge on SDAOUT and SCLOUT Lines on SCLOUT in an attempt to free the bus. A connection n Small 8-Lead (3mm 3mm 0.75mm) DFN and will resume if the stuck bus is cleared. 8-Lead MSOP Packages During insertion, the SDAOUT and SCLOUT lines are pre- charged to 1V to minimize bus disturbances. When driven APPLICATIONS high, the ENABLE input allows the LTC4308 to connect after a stop bit or bus idle condition. Driving ENABLE low breaks n Live Board Insertion the connection between SDAIN and SDAOUT, SCLIN and n Servers SCLOUT. READY is an open-drain output which indicates n Capacitance Buffer/Bus Extender that the backplane and card sides are connected. n RAID Systems n L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. Hot Swap ATCA is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 7032051, 6650174, 6356140. TYPICAL APPLICATION The LTC4308 in a 1.2V 1.2V to 5V Level Shifting Microcontroller Application SDAOUT 5V 1.2V 0.01F 2V/DIV CH1 2.7k 2.7k 10k 2.7k 2.7k V CC LTC4308 SDAIN SCLIN SCLOUT CARD SCL MICRO- CONTROLLER 0.5V/DIV SDAIN SDAOUT CARD SDA CH2 4308 TA01a ENABLE READY READY GND 1s/DIV 4308 TA01b 4308f 1LTC4308 ABSOLUTE MAXIMUM RATINGS (Notes 1, 7) V to GND ................................................. 0.3V to 6V Storage Temperature Range CC SDAIN, SCLIN, SDAOUT, SCLOUT, DFN .................................................... 65C to 125C READY, ENABLE .......................................... 0.3V to 6V MSOP ................................................ 65C to 150C Maximum Sink Current (SDAIN, SCLIN, SDAOUT, Lead Temperature (Soldering, 10 sec) SCLOUT, READY) .............................................. 50mA MSOP ...............................................................300C Operating Temperature Range LTC4308C ................................................ 0C to 70C LTC4308I.............................................. 40C to 85C PIN CONFIGURATION TOP VIEW TOP VIEW ENABLE 1 8 V CC ENABLE 1 8 V CC SCLOUT 2 7 SDAOUT 9 SCLOUT 2 7 SDAOUT SCLIN 3 6 SDAIN 6 SDAIN SCLIN 3 GND 4 5 READY GND 4 5 READY MS8 PACKAGE 8-LEAD PLASTIC MSOP DD PACKAGE 8-LEAD (3mm 3mm) PLASTIC DFN T = 125C, = 200C/W JMAX JA T = 125C, = 43C/W JMAX JA EXPOSED PAD (PIN 9) CONNECTION TO GROUND IS OPTIONAL ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC4308CDD PBF LTC4308CDD TRPBF LBTT 8-Lead (3mm 3mm) Plastic DFN 0C to 70C LTC4308IDD PBF LTC4308IDD TRPBF LBTT 8-Lead (3mm 3mm) Plastic DFN 40C to 85C LTC4308CMS8 PBF LTC4308CMS8 TRPBF LTBTS 8-Lead Plastic MSOP 0C to 70C LTC4308IMS8 PBF LTC4308IMS8 TRPBF LTBTS 8-Lead Plastic MSOP 40C to 85C Consult LTC Marketing for parts speci ed with wider operating temperature ranges. *Temperature grades are identi ed by a label on the shipping container. Consult LTC Marketing for information on non-standard lead based nish parts. For more information on lead free part marking, go to: