Datasheet MAX9690 (Maxim) - 3

Ultra-Fast ECL-Output Comparator MAX9690 SWITCHING CHARACTERISTICS
(V+ = +5V, V- = -5.2V, RL = 50Ω, VT = -2V, TA = +25°C, unless otherwise noted.)
MAX9690C/E MAX9690M PARAMETER SYMBOL CONDITIONS UNITS MIN TYP MAX MIN TYP MAX
TA = +25°C 1.3 1.8 1.3 1.8 Input to Output High tpd+ TA = 0°C to +70°C 1.5 2.0 ns (Notes 1, 2) TA = -55°C to +125°C 1.7 2.4 TA = +25°C 1.3 1.8 1.3 1.8 Input to Output Low tpd- TA = 0°C to +70°C 1.5 2.0 ns (Notes 1, 2) TA = -55°C to +125°C 1.7 2.4
Note 1:
Not tested, guaranteed by design.
Note 2:
VIN = 100mV, VOD = 10mV.
__________Applications Information ____________________Timing Diagram Layout
The timing diagram illustrates the series of events that Because of the MAX9690’s large gain-bandwidth charac- completes the compare function, under worst-case teristic, special precautions need to be taken if its high- conditions. The leading edge of the input signal (illus- speed capabilities are to be used. A PC board with a trated as a large-amplitude, small-overdrive pulse) –– ground plane is mandatory. Mount all decoupling capac- switches the comparator. Outputs Q and Q are similar itors as close to the power-supply pins as possible, and in timing. process the ECL outputs in microstrip fashion, consistent
Definition of Terms
with the load termination of 50Ω to 120Ω. For low-imped- VOS Input Offset Voltage—The voltage required ance applications, microstrip layout at the input may also between the input terminals to obtain 0V differ- be helpful. Pay close attention to the bandwidth of the ential at the output. decoupling and terminating components. Chip compo- nents can be used to minimize lead inductance. VIN Input Voltage Pulse Amplitude VOD Input Voltage Overdrive
Input Slew-Rate Requirements
As with all high-speed comparators, the high gain-band- tpd+ Input to Output High Delay—The propagation width product of these devices creates oscillation prob- delay measured from the time the input signal lems when the input traverses through the linear region. crosses the input offset voltage to the 50% point For clean switching without oscillation or steps in the out- of an output low-to-high transition. put waveform, the input must meet certain minimum slew- tpd- Input to Output Low Delay—The propagation rate requirements. The tendency of the part to oscillate is delay measured from the time the input signal a function of the layout and source impedance of the cir- crosses the input offset voltage to the 50% point cuit employed. Both poor layout and larger source imped- of an output high-to-low transition. ance increase the minimum slew-rate requirement.
_______________________________________________________________________________________ 3