LTC4300A-1/LTC4300A-2 Hot Swappable 2-Wire Bus Buffers FEATURES DESCRIPTION n Bidirectional Buffer for SDA and SCL Lines The LTC 4300A series hot swappable 2-wire bus buffers Increases Fanout allow I/O card insertion into a live backplane without corrup- n Prevents SDA and SCL Corruption During Live tion of the data and clock busses. When the connection is Board Insertion and Removal from Backplane made, the LTC4300A-1/LTC4300A-2 provide bidirectional n Isolates Input SDA and SCL Lines from Output buffering, keeping the backplane and card capacitances 2 2 n Compatible with I C, I C Fast Mode and SMBus isolated. Rise-time accelerator circuitry* allows the use of Standards (Up to 400kHz Operation) weaker DC pull-up currents while still meeting rise-time n Low I Chip Disable: <1A (LTC4300A-1) requirements. During insertion, the SDA and SCL lines are CC n READY Open Drain Output (LTC4300A-1) precharged to 1V to minimize bus disturbances. n 1V Precharge on all SDA and SCL Lines The LTC4300A-1 incorporates a CMOS threshold digital n Supports Clock Stretching, Arbitration and ENABLE input pin, which forces the part into a low current Synchronization mode when driven to ground and sets normal operation n 5V to 3.3V Level Translation (LTC4300A-2) when driven to V . It also includes an open drain READY CC n High Impedance SDA, SCL Pins for V = 0V CC output pin, which indicates that the backplane and card n Small MSOP 8-Pin Package sides are connected together. The LTC4300A-2 replaces the ENABLE pin with a dedicated supply voltage pin, V , CC2 APPLICATIONS for the card side, providing level shifting between 3.3V and 5V systems. Both the backplane and card may be n Hot Board Insertion powered with supply voltages ranging from 2.7V to 5.5V, n Servers with no constraints on which supply voltage is higher. The n Capacitance Buffer/Bus Extender LTC4300A-2 also replaces the READY pin with a digital n Desktop Computer CMOS input pin, ACC, which enables and disables the L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and Hot rise-time accelerator currents. Swap and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. *Protected by U.S. Patents, including 6650174. The LTC4300A is available in a small 8-pin MSOP package. TYPICAL APPLICATION V CC InputOutput Connection t PLH 3.3V C1 0.01F R1 R2 R3 R4 10k 10k 10k 10k OUTPUT INPUT SIDE SIDE SCLIN SCLOUT 50pF 150pF SDAIN SDAOUT LTC4300A-1 ENABLE READY 4300a12 TA02 GND 4300a12 TA01 4300a12fa 1LTC4300A-1/LTC4300A-2 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) TOP VIEW V to GND .................................................... 0.3 to 7V CC ENABLE/V * 1 8 V CC2 CC SCLOUT 2 7 SDAOUT V to GND (LTC4300A-2)............................ 0.3 to 7V CC2 SCLIN 3 6 SDAIN SDAIN, SCLIN, SDAOUT, SCLOUT .................. 0.3 to 7V GND 4 5 READY/ACC* READY, ENABLE (LTC4300A-1) ...................... 0.3 to 7V MS8 PACKAGE 8-LEAD PLASTIC MSOP ACC (LTC4300A-2) ......................................... 0.3 to 7V *LTC4300A-2 T = 125C, = 200C/W Operating Temperature Range JMAX JA LTC4300A-1C/LTC4300A-2C .................... 0C to 70C LTC4300A-1I/LTC4300A-2I ..................40C to 85C Storage Temperature Range .................. 65C to 125C Lead Temperature (Soldering, 10 sec) ...................300C ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LTC4300A-1CMS8 PBF LTC4300A-1CMS8 TRPBF LTABF 8-Lead Plastic MSOP 0C to 70C LTC4300A-1IMS8 PBF LTC4300A-1IMS8 TRPBF LTABG 8-Lead Plastic MSOP 40C to 85C LTC4300A-2CMS8 PBF LTC4300A-2CMS8 TRPBF LTACF 8-Lead Plastic MSOP 0C to 70C LTC4300A-2IMS8 PBF LTC4300A-2IMS8 TRPBF LTACG 8-Lead Plastic MSOP 40C to 85C Consult LTC Marketing for parts specified with wider operating temperature ranges. Consult LTC Marketing for information on nonstandard lead based finish parts. For more information on lead free part marking, go to: