EC5822 datasheet(3/12 Pages) E-CMOS

3 / 12 page

10MHz, Low-Power, CMOS,

Rail-to-Rail Dual Operational Amplifier

EC5822

E-CMOS Corp. (www.ecmos.com.tw)

3K29N-Rev.P001

Page 3 of 12

Rail-to-Rail Output

Rail-to-Rail output swing provides maximum possible dynamic range at the output. This is particularly

important when operating in low supply voltages. The output voltage of EC5822 series can typically swing to

less than 10mV from supply rail in light resisti

ve loads (>100kΩ), and 60mV of supply rail in moderate resistive

loads (10kΩ).

Capacitive Load Tolerance

The EC5822 series can directly drive 250pF capacitive load in unity-gain without oscillation. Increasing the

gain enhances the

amplifier’s ability to drive greater capacitive loads. In unity-gain configurations, the

capacitive load drive can be improved by inserting an isolation resistor RISO in series with the capacitive load,

as shown in Figure 2.

Figure 2. Indirectly Driving a Capacitive Load Using Isolation Resistor

The bigger the RISO resistor value, the more stable VOUT will be. However, if there is a resistive load

RL in parallel with the capacitive load, a voltage divider (proportional to RISO/RL) is formed, this will result in a

gain error. The circuit in Figure 3 is an improvement to the one in Figure 2. RF provides the DC accuracy by

feed-forward the VIN to RL. CF and RISO serve to counteract the loss of phase margin by feeding the high

frequency component of the output signal back to the

amplifier’s inverting input, thereby preserving the phase

margin in the overall feedback loop. Capacitive drive can be increased

Figure 3. Indirectly Driving a Capacitive Load with DC Accuracy

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