Datasheet MAX4014, MAX4017, MAX4019, MAX4022 (Maxim) - 9

Low-Cost, High-Speed, Single-Supply, Gain of +2 Buffers with Rail-to-Rail Outputs in SOT23 MAX4014/MAX4017/MAX4019/MAX4022
20 0 0 -1 -2 -20 µA) µA) -3 -40 -4 -60 -5 -80 -6 -100 INPUT CURRENT ( INPUT CURRENT ( -7 -120 -8 -140 -9 -160 -10 0 100 200 300 400 500 0 100 200 300 400 500 V V IL (mV ABOVE VEE) IL (mV ABOVE VEE) Figure 2. Enable Logic-Low Input Current vs. Enable Logic- Figure 4. Enable Logic-Low Input Current vs. Enable Logic- Low Threshold Low Threshold with 10kΩ Series Resistor ENABLE the output-drive capability, since the buffers have a fixed voltage gain of +2 or -1. 10k For example, a 50Ω load can typically be driven from 40mV above VEE to 1.6V below VCC, or 40mV to 3.4V when operating from a single +5V supply. If the buffer is IN+ EN_ operated in the noninverting, gain of +2 configuration OUT with the inverting input grounded, the effective input MAX40_ _ voltage range becomes 20mV to 1.7V, instead of the -100mV to 2.75V indicated by the Electrical Character- istics. Beyond the effective input range, the buffer out- IN- put is a nonlinear function of the input, but it will not 500Ω 500Ω undergo phase reversal or latchup.
Enable
Figure 3. Circuit to Reduce Enable Logic-Low Input Current The MAX4019 has an enable feature (EN_) that allows the buffer to be placed in a low-power state. When the
Input Voltage Range and Output Swing
buffers are disabled, the supply current will not exceed The input range for the MAX4014 family extends from 550µA per buffer. (VEE - 100mV) to (VCC - 2.25V). Input ground sensing As the voltage at the EN_ pin approaches the negative increases the dynamic range for single-supply applica- supply rail, the EN_ input current rises. Figure 2 shows tions. The outputs drive a 2kΩ load to within 60mV of a graph of EN_ input current versus EN_ pin voltage. the power-suply rails. With heavier loads, the output Figure 3 shows the addition of an optional resistor in swing is reduced as shown in the Electrical Character- series with the EN pin, to limit the magnitude of the cur- istics and the Typical Operating Characteristics. As the rent increase. Figure 4 displays the resulting EN pin load increases, the input range is effectively limited by input current to voltage relationship.
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