LT1720/LT1721 ELECTRICAL CHARACTERISTICSThe l denotes specifi cations that apply over the full operating temperaturerange, otherwise specifi cations are at TA = 25°C. VCC = 5V, VCM = 1V, COUT = 10pF, VOVERDRIVE = 20mV, unless otherwise specifi ed.SYMBOLPARAMETERCONDITIONSMINTYPMAXUNITS ΔtPD Differential Propagation Delay (Note 9) Between Channels 0.3 1.0 ns tSKEW Propagation Delay Skew (Note 10) Between tPDLH/tPDHL 0.5 1.5 ns tr Output Rise Time 10% to 90% 2.5 ns tf Output Fall Time 90% to 10% 2.2 ns tJITTER Output Timing Jitter VIN = 1.2VP-P (6dBm), ZIN = 50Ω tPDLH 15 psRMS VCM = 2V, f = 20MHz tPDHL 11 psRMS fMAX Maximum Toggle Frequency VOVERDRIVE = 50mV, VCC = 3V 70.0 MHz VOVERDRIVE = 50mV, VCC = 5V 62.5 MHz Note 1: Stresses beyond those listed under Absolute Maximum Ratings Note 6: Because of internal hysteresis, there is no small-signal region may cause permanent damage to the device. Exposure to any Absolute in which to measure gain. Proper operation of internal circuity is ensured Maximum Rating condition for extended periods may affect device by measuring VOH and VOL with only 10mV of overdrive. reliability and lifetime. Note 7: Propagation delay measurements made with 100mV steps. Note 2: If one input is within these common mode limits, the other input Overdrive is measured relative to V ± TRIP . can go outside the common mode limits and the output will be valid. Note 8: tPD cannot be measured in automatic handling equipment with Note 3: The LT1720/LT1721 comparators include internal hysteresis. low values of overdrive. The LT1720/LT1721 are 100% tested with a The trip points are the input voltage needed to change the output state in 100mV step and 20mV overdrive. Correlation tests have shown that each direction. The offset voltage is defi ned as the average of V + TRIP and tPD limits can be guaranteed with this test, if additional DC tests are V – TRIP , while the hysteresis voltage is the difference of these two. performed to guarantee that all internal bias conditions are correct. Note 4: The common mode rejection ratio is measured with VCC = 5V Note 9: Differential propagation delay is defi ned as the larger of the two: and is defi ned as the change in offset voltage measured from VCM = –0.1V ΔtPDLH = tPDLH(MAX) – tPDLH(MIN) to VCM = 3.8V, divided by 3.9V. ΔtPDHL = tPDHL(MAX) – tPDHL(MIN) Note 5: The power supply rejection ratio is measured with VCM = 1V and where (MAX) and (MIN) denote the maximum and minimum values is defi ned as the change in offset voltage measured from VCC = 2.7V to of a given measurement across the different comparator channels. VCC = 6V, divided by 3.3V. Note 10: Propagation Delay Skew is defi ned as: tSKEW = |tPDLH – tPDHL| TYPICAL PERFORMANCE CHARACTERISTICSInput Offset and Trip VoltagesInput Offset and Trip VoltagesInput Common Mode Limitsvs Supply Voltagevs Temperaturevs Temperature 3 3 4.2 VCC = 5V V + + TRIP VTRIP 2 2 4.0 3.8 1 1 VOS VOS 3.6 0 0 0.2 –1 –1 V – – TRIP VTRIP 0 AND TRIP POINT VOLTAGE (mV) AND TRIP POINT VOLTAGE (mV) OS –2 OS –2 –0.2 V 25°C V COMMON MODE INPUT VOLTAGE (V) VCM = 1V –3 –3 –0.4 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 –50 –25 0 25 50 75 100 125 –50 –25 0 25 50 75 100 125 SUPPLY VOLTAGE (V) TEMPERATURE (°C) TEMPERATURE (°C) 17201 G01 17201 G02 17201 G03 17201fc 4