LTC4302-1/LTC4302-2 Addressable 2-Wire Bus Buffers FEATURES DESCRIPTIO 2 n Bidirectional Buffer for SDA and SCL Lines The LTC 4302-1/LTC4302-2 addressable I C bus and Increases Fanout SMBus compatible bus buffers allow a peripheral board n Connect SDA and SCL Lines with 2-Wire Bus to be inserted and removed from a live backplane without Commands corruption of the bus. The LTC4302-1/LTC4302-2 main- n Prevents SDA and SCL Corruption During Live Board tain electrical isolation between the backplane and periph- Insertion and Removal from Backplane eral board until their V supply is valid and a master CC TM 2 2 n Compatible with I C Standard Mode, I C Fast device on the backplane side addresses the LTC4302-1/ Mode and SMBus Standards LTC4302-2 and commands them to connect. The n Rise Time Accelerators on SDA, SCL Lines LTC4302-1/LTC4302-2s ADDRESS pin provides 32 pos- n 1V Precharge on SDA and SCL Lines sible addresses set by an external resistive divider be- n 32 Unique Addresses from a Single ADDRESS Pin tween V and GND. The LTC4302-1/LTC4302-2 work CC n Two General Purpose Inputs-Outputs (LTC4302-1) with supply voltages ranging from 2.7V to 5.5V. The SDA n Translates Between 5V and 3.3V Systems and SCL inputs and outputs do not load the bus lines when (LTC4302-2) V is low. CC n Small 10-Pin MSOP Package Rise time accelerator circuitry* allows for heavier capaci- tive bus loading while still meeting system timing require- U ments. During insertion, the SDA and SCL lines are APPLICATIO S precharged to 1V to minimize bus disturbances. Two n Live Board Insertion general purpose input/output pins (GPIOs) on the n 5V/3.3V Level Translator LTC4302-1 can be configured as inputs, open-drain out- n Servers puts or push-pull outputs. The LTC4302-2 option replaces n Capacitance Buffer/Bus Extender one GPIO pin with a second supply voltage pin V , CC2 n Nested Addressing providing level shifting between systems with different , LTC and LT are registered trademarks of Linear Technology Corporation. supply voltages. The LTC4302-1/LTC4302-2 are available 2 I C is a trademark of Philips Electronics N.V. *U.S. Patent No. 6,650,174 in a 10-pin MSOP package. TYPICAL APPLICATIO Input-Output Connection t PLH 2.7V to C1 5.5V R3 R4 R1 R5 R6 R7 R8 R9 0.01F V 10k CC 10k 10k 1870 10k 10k 1k 1k OUTPUT INPUT LTC4302-1 SDA CARD SDA SIDE SIDE SDAIN SDAOUT SCL CARD SCL 50pF 150pF SCLIN SCLOUT CONN LED ADDRESS GPIO2 LED R2 GPIO1 2000 4203 TA01a GND 4032 F10 0.1m s/DIV sn430212 430212fs 1 U ULTC4302-1/LTC4302-2 ABSOLUTE AXI U RATI GS (Note 1) V to GND ................................................. 0.3V to 7V Operating Temperature Range CC SDAIN, SCLIN, SDAOUT, SCLOUT, LTC4302C-1/LTC4302C-2 ...................... 0 C to 70 C GPIO1, CONN, GPIO2 (LTC4302-1), LTC4302I-1/LTC4302I-2 .................... 40 C to 85 C V (LTC4302-2)........................................ 0.3V to 7V Storage Temperature Range ................. 65 C to 125 C CC2 ADDRESS ....................................... 0.3V to V + 0.3V Lead Temperature (Soldering, 10 sec).................. 300 C CC UUW PACKAGE/ORDER I FOR ATIO ORDER PART ORDER PART TOP VIEW TOP VIEW NUMBER NUMBER SDAIN 1 10 SDAOUT SDAIN 1 10 SDAOUT SCLIN 2 9 SCLOUT SCLIN 2 9 SCLOUT LTC4302CMS-1 LTC4302CMS-2 CONN 3 8 V CONN 3 8 V CC CC ADDRESS 4 7 GPIO2 LTC4302IMS-1 ADDRESS 4 7 V LTC4302IMS-2 CC2 GND 5 6 GPIO1 GND 5 6 GPIO1 MS PART MARKING MS PART MARKING MS PACKAGE MS PACKAGE 10-LEAD PLASTIC MSOP 10-LEAD PLASTIC MSOP LTYF LTABY T = 125 C, q = 130 C/W T = 125 C, q = 130 C/W JMAX JA JMAX JA LTYG LTABZ Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T = 25 C. A V = 2.7V to 5.5V (LTC4302-1), V = V = 2.7V to 5.5V (LTC4302-2) unless otherwise noted. CC CC CC2 SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Power Supply/Start-Up V Positive Supply Voltage LTC4302-1 l 2.7 5.5 V CC V Card Side Supply Voltage LTC4302-2 l 2.7 5.5 V CC2 I Supply Current V = 0V, V = 5.5V (Note 2) LTC4302-1 l 5.9 8 mA CC SDAIN CC I V Supply Current V = 0V, V = V = 5.5V l 3.4 5 mA VCC CC SDAIN CC CC2 (Note 2) LTC4302-2 I V Supply Current V = 0V, V = V = 5.5V l 2.3 4 mA VCC2 CC2 SDAIN CC CC2 (Note 2) LTC4302-2 V UVLO Upper Threshold V Rising l 2.5 2.7 V UVLOU CC V UVLO Lower Threshold V Falling 2.35 V UVLOL CC V V UVLO Upper Threshold LTC4302-2 l 2.5 2.7 V UVLO2U CC2 V V UVLO Lower Threshold LTC4302-2 2.35 V UVLO2L CC2 V Precharge Voltage SDA, SCL Floating l 0.8 1 1.2 V PRE V CONN Threshold Voltage l 0.8 1.5 2.2 V THCONN t CONN Delay, On-Off 60 ns PHL t CONN Delay, Off-On 20 ns PLH sn430212 430212fs 2 U WWW