LTC1694-1 2 SMBus/I C Accelerator* FEATURES DESCRIPTIO TM 2 n Improves SMBus/I C Rise Time Transition The LTC 1694-1 is a dual SMBus active pull-up designed n Ensures Data Integrity with Multiple Devices to enhance data transmission speed and reliability under 2 on the SMBus/I C all specified SMBus loading conditions. The LTC1694-1 is 2 n Improves Low State Noise Margin also compatible with the Philips I C Bus. n Wide Supply Voltage Range: 2.7V to 6V The LTC1694-1 allows multiple device connections or a n Parallel Multiple LTC1694-1 Devices longer, more capacitive interconnect, without compro- for Increased Drive mising slew rates or bus performance, by supplying a high TM n Low Profile (1mm) SOT-23 (ThinSOT ) Package 2 pull-up current of 2.2mA to slew the SMBus or I C lines during positive bus transitions U APPLICATIO S During negative transitions or steady DC levels, the LTC1694-1 sources zero current. External resistors, one n Notebook and Palmtop Computers on each bus line, trigger the LTC1694-1 during positive n Portable Instruments bus transitions and set the pull-down current level. These n Battery Chargers resistors determine the slew rate during negative bus n Industrial Control Application transitions and the logic low DC level. n TV/Video Products The LTC1694-1 is available in a 5-pin SOT-23 package. n ACPI SMBus Interface , LTC and LT are registered trademarks of Linear Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation. 2 I C is a trademark of Philips Electronics N.V. *U.S. Patent No. 6,650,174 TYPICAL APPLICATIO Comparison of SMBus Waveforms for V V CC CC the LTC1694-1 vs Resistor Pull-Up 5V 5V V SMBus1 CC C1 LTC1694-1 0.1F R R GND SMBus2 P1 P2 LTC1694-1 1V/DIV SCL R PULL-UP = 15.8k SMBus SDA CLK DATA CLK DATA IN IN IN IN CLK DATA CLK DATA OUT OUT OUT OUT V = 5V 1m s/DIV 1694-1 TA02 CC DEVICE 1 DEVICE N C = 200pF LD f = 100kHz SMBus 1694-1 TA01 16941fa 1 U ULTC1694-1 ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION (Note 1) ORDER PART Supply Voltage (V ) ................................................. 7V TOP VIEW CC NUMBER SMBus1, SMBus2 Inputs ............ 0.3V to (V + 0.3V) CC V 1 5 SMBus1 CC Operating Ambient Temperature Range GND 2 LTC1694-1CS5 NC 3 4 SMBus2 LTC1694-1C ........................................... 0 C to 70 C LTC1694-1IS5 LTC1694-1I ....................................... 40 C to 85 C S5 PACKAGE S5 PART MARKING 5-LEAD PLASTIC TSOT-23 Junction Temperature........................................... 125 C T = 125 C, q = 256 C/ W Storage Temperature Range ................. 65 C to 150 C JMAX JA LTHE Lead Temperature (Soldering, 10 sec.)................. 300 C LTA9 Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS The l denotes specifications which apply over the full operating temperature range, otherwise specifications are at T = 25 C. V = 2.7V to 6V, unless otherwise noted. A CC SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V Supply Voltage Range 2.7 6 V CC I Supply Current SMBus1 = SMBus2 = V l 15 45 80 m A CC CC I Pull-Up Current Positive Transition on SMBus ( Figure 1) l 1.0 2.2 mA PULL-UP Slew Rate = 0.5V/m s, SMBus > V THRES V Input Threshold Voltage Slew Rate = 0.5V/m s (Figure 1) l 0.4 0.65 0.9 V THRES SR Slew Rate Detector Threshold SMBus > V l 0.2 0.5 V/m s THRES THRES t SMBus Rise Time Bus Capacitance = 200pF (Note 2) l 0.32 1.0 m s r 2 Standard Mode I C Bus Rise Time Bus Capacitance = 400pF (Note 3) l 0.30 1.0 m s f SMBus Maximum Operating Frequency (Note 4) l 100 kHz MAX 2 Note 1: Absolute Maximum Ratings are those values beyond which the life Note 3: The rise time of an I C bus line is calculated from V to IL(MAX) of a device may be impaired. V or 1.5V to 3V (with V = 5V). This parameter is guaranteed by IH(MIN) CC design and not tested. With a minimum boosted pull-up current of 1mA: Note 2: The rise time of an SMBus line is calculated from (V IL(MAX) 0.15V) to (V + 0.15V) or 0.65V to 2.25V. This parameter is Rise Time = (3V 1.5V) 400pF/1mA = 0.6m s IH(MIN) guaranteed by design and not tested. With a minimum initial slew rate of Note 4: This parameter is guaranteed by design and not tested. 0.5V/m s, a minimum pull-up current of 1mA and a maximum input threshold voltage of 0.9V: Rise Time = (0.9V 0.65V)/0.5V/m s + (2.25V 0.9V) 200pF/1mA = 0.77m s 16941fa 2 U W U W U WW