EC5758 datasheet(3/12 Pages) E-CMOS

3 / 12 page

1MHz, Low Power, CMOS, EMI Hardened,

Rail-to-Rail Dual Operational Amplifier

EC5758

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

3L27N-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 EC5758 series can typically swing to less than 10mV

from supply rail in

light resistive loads (>100kΩ), and 60mV of supply rail in moderate resistive loads (10kΩ).

Capacitive Load Tolerance

The EC5758 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 by increasing the value of CF. This in turn will slow down the pulse response.

Figure 3. Indirectly Driving a Capacitive Load with DC Accuracy

Differential amplifier

The differential amplifier allows the subtraction of two input voltages or cancellation of a signal common the two

inputs. It is useful as a computational amplifier in making a differential to single-end conversion or in rejecting a

common mode signal. Figure 4. shown the differential amplifier using EC5758.

EC5758 Datasheet(PDF) 3 Page - E-CMOS Corporation