LTC4307 Low Offset Hot Swappable 2-Wire Bus Buffer with Stuck Bus Recovery DESCRIPTIO FEATURES Bidirectional Buffer with Stuck Bus Recovery The LTC 4307 hot swappable, 2-wire bus buffer allows 60mV Buffer Offset Independent of Load I/O card insertion into a live backplane without corrup- 30ms Stuck Bus Timeout tion of the data and clock busses. The LTC4307 provides 2 Compatible with Non-Compliant V I C Devices bidirectional buffering, keeping the backplane and card OL Prevents SDA and SCL Corruption During Live capacitances isolated. Low offset and high V tolerance OL Board Insertion and Removal from Backplane allows multiple devices to be cascaded on the clock and 5kV Human Body Model ESD Protection data busses. If SDAOUT or SCLOUT are low for 30ms, the Isolates Input SDA and SCL Line from Output LTC4307 will automatically break the bus connection. At 2 TM 2 Compatible with I C , I C Fast Mode and SMBus this time the LTC4307 automatically generates up to 16 READY Open-Drain Output clock pulses on SCLOUT in an attempt to free the bus. A 1V Precharge on All SDA and SCL Lines connection will resume if the stuck bus is cleared. High Impedance SDA, SCL Pins for V = 0V CC During insertion, the SDA and SCL lines are pre-charged Small 8-Lead (3mm 3mm) DFN and 8-Lead MSOP to 1V to minimize bus disturbances. When driven high, Packages the ENABLE input allows the LTC4307 to connect after a U stop bit or bus idle. Driving ENABLE low breaks the con- APPLICATIO S nection between SDAIN and SDAOUT, SCLIN and SCLOUT. READY is an open-drain output which indicates that the Live Board Insertion backplane and card sides are connected. Servers , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. Capacitance Buffer/Bus Extender All other trademarks are the property of their respective owners. RAID Systems Protected by U.S. Patents, including 7032051, 6356140, 6650174 ATCA TYPICAL APPLICATIO 3.3V Rising Edge from Asserted Low 0.01F 1000 10k 10k 2.7k 2.7k 10k 10k 0.01F V V CC CC ENABLE ENABLE 800 100k LTC4307 LTC4307 MICRO- CONTROLLER SCLIN SCLOUT SCLIN SCLOUT CARD SCL 600 LOW OFFSET SDAOUT SDAIN SDAOUT SDAIN SDAOUT CARD SDA 400 3.3V 3.3V SDAIN 10k 10k 200 READY READY GND GND 4307 TA01a 0 0 100 200 300 400 500 600 100ns/DIV 4307 TA01b BACKPLANE CARD CARD CONNECTOR CONNECTOR 4307f 1 200mV/DIV U ULTC4307 ABSOLUTE AXI U RATI GS (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 LTC4307C ................................................ 0C to 70C LTC4307I ............................................. 40C to 85C UUW PACKAGE/ORDER I FOR ATIO ORDER PART ORDER PART TOP VIEW NUMBER NUMBER ENABLE 1 8 V CC TOP VIEW LTC4307CDD LTC4307CMS8 SCLOUT 2 7 SDAOUT ENABLE 1 8 V CC 9 LTC4307IDD SCLOUT 2 7 SDAOUT LTC4307IMS8 SCLIN 3 6 SDAIN SCLIN 3 6 SDAIN GND READY 4 5 GND 4 5 READY DD PART* MS8 PART* MS8 PACKAGE 8-LEAD PLASTIC MSOP DD PACKAGE MARKING MARKING 8-LEAD (3mm 3mm) PLASTIC DFN T = 125C, = 200C/W JMAX JA T = 125C, = 43C/W JMAX JA LBTW LTBTV EXPOSED PAD (PIN 9) CONNECTION TO GND IS OPTIONAL LBTW LTBTV 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. The ELECTRICAL CHARACTERISTICS denotes the speci cations which apply over the full operating temperature range, otherwise speci cations are at T = 25C. V = 3.3V, unless otherwise noted. A CC SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Power Supply V Positive Supply Voltage 2.3 5.5 V CC I Supply Current V = 5.5V, V = V = 0V (Note 6) 811 mA CC CC SCLOUT SDAOUT I Shutdown Supply Current V = 5.5V, ENABLE = GND, SDA, SCL = 5.5V 900 1200 A SD CC V Precharge Voltage SDA, SCL Floating 0.8 1 1.2 V PRE t Bus Idle Time 55 95 175 s IDLE V ENABLE Threshold 0.8 1.4 2 V THR ENABLE I ENABLE Input Current ENABLE from 0V to V 0.1 5 A ENABLE CC t ENABLE Delay Off-On V = 3.3V (Figure 1) 95 s PLH EN CC t ENABLE Delay On-Off V = 3.3V (Note 3) (Figure 1) 10 ns PHL EN CC t READY Delay Off-On V = 3.3V (Note 3) (Figure 1) 10 ns PLH READY CC t READY Delay On-Off V = 3.3V (Note 3) (Figure 1) 10 ns PHL READY CC V READY Output Low Voltage I = 3mA, V = 2.3V 0.4 V OL READY PULLUP CC I READY Off Leakage Current V = READY = 5.5V 0.1 5 A OFF READY CC 4307f 2 U WWW