LTC4311ISC6#TRMPBF

LTC4311 Low Voltage I2C/SMBus Accelerator FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTION Improves I2C Bus Rise Time Transition Ensures Data Integrity with Multiple Devices on the I2C Bus. Wide Supply Voltage Range: 1.6V to 5.5V Improves Low State Noise Margin Up to 400kHz Operation Auto Detect Low Power Standby Mode Low ( VTHR, VCC = 1.8V, 5.5V ● tr Fast Mode I2C Bus Rise Time Bus Capacitance = 400pF, VCC = 3V (Note 4) ● fMAX Bus Maximum Operating Frequency (Note 5) ● Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: All currents into pins are positive. All voltages are referenced to GND unless otherwise specified. Note 3: Thermal characteristics are determined with exposed pad soldered to GND plane. If the exposed pad is left open, thermal characteristics can be drastically different. 2.5 5 mA 300 400 ns kHz Note 4: The rise time of an I2C bus line is calculated from VIL(MAX) to VIH(MIN) or 0.9V to 2.1V (with VCC = 3V). This parameter is guaranteed by design and not tested. With a minimum boosted pull-up current of 2.5mA: Rise Time = (2.1V – 0.9V) • 400pF/2.5mA = 0.19μs. Note 5: Determined by design, not tested in production. 4311fa 3 LTC4311 TYPICAL PERFORMANCE CHARACTERISTICS (TA = 25°C, unless otherwise indicated) Boost Pull-Up Current vs Bus Capacitance Boost Pull-Up Current vs Temperature 60 RP = 4.7kΩ CBUS = 1nF 35 30 VCC = 5.5V 25 20 15 10 5 VCC = 3.3V VCC = 2.5V 40 30 VCC = 3.3V 20 VCC = 2.5V 10 VCC = 1.8V 60 40 20 TEMPERATURE (°C) 0 80 0 100 0 VCC = 1.8V VCC = 5.5V VCC = 2.5V 250 VCC = 3.3V VCC = 3.3V BUS1 = BUS2 = 0V RISE TIME (ns) SUPPLY CURRENT (μA) 5000 4311 G02 300 190 170 160 2000 3000 4000 CAPACITANCE (pF) Rise Time vs Capacitance Supply Current vs Temperature VCC = 2.5V 200 150 VCC = 5.5V 100 150 140 60 40 20 TEMPERATURE (°C) 0 80 0 100 0 2000 3000 4000 CAPACITANCE (pF) 5000 4311 G04 Bus Input Threshold Voltage vs Supply Voltage 0.8 28 0.75 INPUT THRESHOLD (V) 30 VCC = 5.5V 24 22 1000 4311 G03 Standby Current vs Temperature 26 RP = 2kΩ Measured from 0.3 • VCC to 0.7 • VCC 50 VCC = 1.8V 130 –40 –20 STANDBY CURRENT (μA) 1000 4311 G01 210 180 VCC = 5.5V VCC = 1.8V 0 –40 –20 200 Rp = 2kΩ 50 BOOST PULL-UP CURRENT (mA) BOOST PULL-UP CURRENT (mA) 40 VCC = 3.3V 20 0.7 0.65 0.6 0.55 0.5 VCC = 2.5V 18 0.45 VCC = 1.8V 16 –40 –20 0.4 40 20 60 0 TEMPERATURE (°C) 80 100 4311 G05 1 2 3 4 SUPPLY VOLTAGE (V) 5 6 4311 G06 4311fa 4 LTC4311 PIN FUNCTIONS BUS1: Active Pull-up for Bus. Connect to either clock line or data line for 2-wire bus. EXPOSED PAD (DFN Package Only): Exposed Pad may be left open or connected to device ground. BUS2: Active Pull-up for Bus. Connect to either clock line or data line for 2-wire bus. GND: Device Ground. Connect this pin to a ground plane for best results. ENABLE: Device Enable Input. This is a 1V nominal digital threshold input pin. For normal operation drive ENABLE to a voltage greater than 1.5V. Driving ENABLE below the 0.4V threshold puts the device in a low (