LTC4309 Level Shifting Low Offset Hot Swappable 2-Wire Bus Buffer with Stuck Bus Recovery FEATURES DESCRIPTION n Bidirectional Buffer Increases Fanout The LTC 4309 hot swappable 2-wire bus buffer allows n 60mV Buffer Offset Independent of Load I/O card insertion into a live backplane without corrup- n Optional Disconnect when Bus is Stuck Low tion of the data and clock busses. The LTC4309 provides n Prevents SDA and SCL Corruption During Live bidirectional buffering, keeping the backplane and card Board Insertion and Removal from Backplane capacitances isolated. Low offset and high V tolerance OL n Level Shift 2.5V, 3.3V and 5V Busses allows cascading of multiple devices on the clock and data 2 n Compatible with Non-Compliant V I C Devices busses. If SDAOUT or SCLOUT are low for 30ms, FAULT OL n 6kV Human Body Model ESD Ruggedness will pull low indicating a stuck bus low condition. If DISCEN n Isolates Input SDA and SCL Lines from Output is tied high, the LTC4309 will automatically break the bus 2 2 n Compatible with I C, I C Fast-Mode and SMBus connection and generate up to 16 clock pulses and a stop n READY Open Drain Output bit in an attempt to free the bus. A connection will resume n FAULT Open Drain Output if the stuck bus is cleared. If DISCEN is connected to GND, n 1V Precharge on All SDA and SCL Lines the busses will remain connected with no clock or stop n Optional Rise Time Accelerators bit generation. ACC input enables rise-time accelerators n High Impedance SDA, SCL Pins for V = 0 for high capacitively loaded busses. CC n Available in Small 12-Pin DFN (4mm x 3mm) and During insertion, the SDA and SCL lines are precharged to 16-Lead SSOP Packages 1V to minimize bus disturbances. When driven high, the ENABLE input allows the LTC4309 to connect after a stop bit or bus idle. Driving ENABLE low breaks the connection APPLICATIONS between SDAIN and SDAOUT, SCLIN and SCLOUT. READY n Live Board Insertion is an open drain output which indicates that the backplane n Servers and card sides are connected. n Capacitance Buffer/Bus Extender L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other n RAID Systems trademarks are the property of their respective owners. Protected by U.S. Patents including 6356140, 6650174, 7032051. n ATCA TYPICAL APPLICATION 3.3V Rising Edge from Asserted Low 5V 0.01 F 1000 10k 10k 0.01 F V V CC CC V V CC2 CC2 800 EN ENABLE ACC ENABLE ACC 2.7k 2.7k 100k LTC4309 LTC4309 10k 10k 600 LOW OFFSET SDAOUT SCL1 SCLIN SCLOUT SCLIN SCLOUT SCL2 400 SDA2 SDA1 SDAIN SDAOUT SDAIN SDAOUT SDAIN 3.3V 5V 3.3V 200 5V DISCEN 10k DISCEN 10k 0 READY 10k READY 10k 0 100 200 300 400 500 600 100ns/DIV FAULT FAULT FAULT FAULT 4309 G01 GND GND BACKPLANE CARD 4309 TA01 CONNECTOR CONNECTOR 4309fa 1 200mV/DIVLTC4309 ABSOLUTE MAXIMUM RATINGS (Note 1, 6) V , V to GND ............................................0.3 to 6V Operating Temperature CC CC2 SDAIN, SCLIN, SDAOUT, SCLOUT, READY, LTC4309C ................................................ 0C to 70C ENABLE, FAULT, ACC, DISCEN .......................0.3 to 6V LTC4309I.............................................. 40C to 85C Maximum Sink Current (SDA, SCL, FAULT, READY) Storage Temperature Range (DE)........... 65C to 125C I ......................................................................50mA Storage Temperature Range (GN) .......... 65C to 150C SINK Lead Temperature (Soldering, 10 sec) GN Package ......................................................300C PIN CONFIGURATION TOP VIEW TOP VIEW 1 ENABLE 16 V CC ENABLE 1 12 V CC 2 NC 15 NC DISCEN 2 11 V CC2 3 DISCEN 14 V CC2 SCLOUT 3 10 SDAOUT 4 SCLOUT 13 SDAOUT 13 SCLIN 4 9 SDAIN SCLIN 5 12 SDAIN 8 FAULT ACC 5 ACC 6 11 FAULT GND 6 7 READY NC 7 10 NC GND 8 9 READY DE12 PACKAGE 12-LEAD (4mm 3mm) PLASTIC DFN GN PACKAGE T = 125C, = 43C/W JMAX JA 16-LEAD NARROW PLASTIC SSOP EXPOSED PAD (PIN 13) PCB CONNECTION TO GND IS OPTIONAL T = 150C, = 110C/W JMAX JA ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC4309CDE PBF LTC4309CDE TRPBF 4309 12-Lead (4mm 3mm) Plastic DFN 0C to 70C LTC4309IDE PBF LTC4309IDE TRPBF 4309 12-Lead (4mm 3mm) Plastic DFN 40C to 85C LTC4309CGN PBF LTC4309CGN TRPBF 4309 16-Lead Plastic SSOP 0C to 70C LTC4309IGN PBF LTC4309IGN TRPBF 4309I 16-Lead Plastic SSOP 40C to 85C Consult LTC Marketing for parts speci ed with wider operating temperature ranges. *The temperature grade is 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: