Features

gain bandwidth multiplication: 5.5MHz

Low noise: 7.5nv/√Hz

#8226 at 1kHz

#8226 ; Offset voltage: 1MV (maximum)

Enter bias current: 0.2Pa

The unit gain is stable

EMI input filter

Static current: 0.76ma/ch

power supply voltage: 2.2V to 5.5 V

Small packaging: SC70, SOT23 and MSOP

Optical diode front placement large

#8226 ; Corpox sensor front placement big device

sensor signal regulation

audio equipment

123] Explanation

OPA377 series operational amplifier is a broadband CMOS amplifier. When working at a low static current of 0.76ma (typical), it provides very low noise, low input bias current and low offset voltage voltage Essence

OPA377 operational amplifier is optimized for low voltage and single power supply. The excellent combination of communication and DC performance makes it an ideal choice for widespread application, including small signal adjustment, audio and active filters. In addition, these components have a wide range of supply scope and excellent power suppression ratio, making it attractive applications and operate directly from the battery without supervision.

OPA377 has SC70-5, SOT23-5, and SO-8 software packages. OPA2377 and MSOP-2377 are provided in the double packaging of OPA438. All models work at a temperature of -40 ° C to+125 ° C.

Typical features

Unless otherwise explained, it is in TA u003d+25 ° C, vs u003d+5V, RL u003d 10K #8486 ; Connect to vs/2, vcm u003d vs/2, vout u003d vs/2.

Application information Working characteristics OPA3777777 The parameters of the series amplifier are from 2.2V to 5.5V (± 1.1V and ± 2.75V) is completely specified. Many specifications are suitable for -40 ° C to+125 ° C. The typical features are given significant parameters related to work voltage or temperature. Total plane layout guide

In order to obtain the best equipment operation performance, a good printing circuit board (PCB) layout practice requires. Low losses, 0.1MF bypass capacitors must be connected between the feet and grounding of each power, and as close to the device as much as possible. Single+V power supply is suitable for single V ground.

Basic amplifier configuration

OPA377 family unity and stability. When the input is input, it does not reverse the output phase. The typical single power connection is shown in Figure 21. OPA377 is configured to a basic inverter amplifier with a gain to 10V/V. The output of this single power supply is centered on the co -mode voltage VCM. For the circuit shown, this voltage is 2.5 volts, but it may be any value within the range input voltage range.

Common mode voltage range

The input co -mode voltage range of the OPA377 series exceeds 100mV of the power rail. The offset voltage of the amplifier is very low, from about (V-) to (V+)-1V, as shown in Figure 22. When the covarurative voltage exceeds (V+) -1V, the offset voltage increases. Common modular suppression from (V-) to (V+) -1.3V.

Input and ESD Protection

OPA377 series integrates internal static discharge (ESD) protection circuits on all pins. For input and output pins, this protection is mainly composed of a current -controlled diode connected between input and power pins. These ESD protection diode also provides a circuit and input -driven protection. As long as the current is limited to the absolute maximum value of 10mA rating. Figure 23 shows how to add the series input resistor to the driver input to limit the input current. This additional resistor will generate heat noise in the amplifier input terminal, and its value should be kept at minimal value in the application of sensitivity to noise.

Electromagnetic interference sensitivity and input filtering

The sensitivity of the operation amplifier to electromagnetic interference (EMI) is different. If the transmission EMI enters the computing amplifier, when the EMI exists, the DC offset observed at the amplifier output place may deviate from the nominal value. This offset is the result of the rectification of signal related to internal semiconductor knots. Although all the amplifier pin function will be affected by electromagnetic interference, the input pin may be the most vulnerable. The OPA377 operational amplifier series integrates an internal input low -pass filter to reduce the response of the amplifier to EMI. Enter the filter to provide co -mode and differential filtering. The cut -off frequency of this filter is about 75MHz (–3DB), and attenuation of 20 yearsDB.

Capability load and stability

OPA377 series amplifier can be used in applications that need to drive capacitance loads. Like all operational amplifiers, there may be OPAX377 unstable, leading to the specific situation of oscillation. When determining whether a amplifier can stabilize, the factors that need to be considered include: specific op amp circuit configuration, layout, gain, and output load. The unit gain (+1V/v) The operating amplifier driving capacitance load ratio in the buffer structure shows a greater instability trend of the amplifier that works under higher noise gain. Together with the output resistance of the computing amplifier, the capacitance load generates a pole in the feedback loop, reducing the phase profit margin as the capacity load increases, and the degradation of phase margin also increases.

OPAX377 configured in the unit gain can directly drive up to 250pf pure capacitor load. Increasing gain and enhancement of the capacity of the amplifier driver is more capacitive load; see typical feature curves, small signals over pumping and capacitance load. In the unit gain configuration, the capacitance load driver can be improved by inserting a small (10 to 20 ) resistor RS and output series, as shown in Figure 24. This resistor significantly reduces the bell while maintaining the DC performance of pure capacitance load. However, if the resistor load is connected to the capacitor load, the pressure division will be generated, the gain error is introduced at the output end, and the output swing is slightly reduced. The introduction of error and ratio RS/RL is proportional, and it can usually be ignored at low output current levels.

Active filter

OPA377 series is very suitable for the filter application amplifier that requires broadband width, rapid conversion rate, low noise, and single power operation. Figure 25 shows 50kHz, second -order, and low via filters can provide the maximum flat Bartworth response. In addition to the cut -off frequency, the rolling is -40dB/DEC. Butterworth response is very suitable for applications that require predictable gain characteristics, such as anti -hybrid filters used before the modulus converter (ADC).

Drive mold number converter

The low noise and width and width of the OPA377 series make it ADC. , 250KSPS converter. The amplifier is connected to a unit gain without a conversion buffer.