Features

0 ° C to 70 ° C. Knowing good molds

separation (saw) mold installed on a wafer belt

Control the baseline

Low static current (IQ): 45μA (typical value)

low cost

#8226; Rail -to -track input and output

Single power supply: 2.1 v to 5.5 v

Input bias current: 0.5 PA (typical value) [123 123 ]

Portable device

battery power supply equipment

Smoke Alarm

Carbon monoxide detector

A single power supply low -power CMOS operational amplifier. OPA2348 has a 1MHz expansion bandwidth and 45μA power current, which is suitable for low -power applications from 2.1V to 5.5V.

The low power current of 45μA and the input bias current of 0.5Pa make OPA2348 the best choice for low -power high impedance applications (such as smoke detectors and other sensors).

Order information

Application information OPA2348 computing amplifier units are stable, suitable for extensive universal applications application. OPA2348 has broadband bands and unit gain stability, and has rail -to -rail input and output to increase the dynamic range. Figure 1 shows the input and output waveform of OPA2348 in the unit gain configuration. The operation is powered by a single 5 V power supply, and the load is connected to VS/2. The input is 5-VPP sine waves. The output voltage is about 4.98 VPPEssence Ceramic capacitors should be a bypass container with 0.01μF.

Working voltage

OPA2348's regulations and test scope of computing amplifier is 2.5 V to 5.5 V. However, the power supply voltage may be between 2.1 V and 5.5 V. The parameters are tested within the specified power supply range, which is a unique feature of OPA2348. In addition, all temperature specifications are suitable for 0 ° C to 70 ° C. Without the entire working voltage range, most of the performance remains almost unchanged. The typical feature shows the parameters that significantly changes with the working voltage or temperature.

Common mode voltage range

The input co -mode voltage range of OPA2348 exceeds 200 millivolves of the power rail. This is achieved through a complementary input level and a N channel input differential parallel parallel parallel parallel parallel. For the input voltage near the track, the N channel is in active state, usually (V+) -1.2 V to 300 MV above the positive electrode power supply, and the P channel is to about 300 MV below the negative electrode power supply to approximately (V+)-1.4 V. The input voltage is the opening state. There is a small transition area, usually (V+) -1.4 V to (V+) -1.2 V, both pairs. The 200 MV transition zone shown in Figure 2 can change ± 300 MV with the process. Therefore, at the low-end, the range of the transition zone (both stages) is (V+)-1.7 V to (V+)-1.5 V, and high-end (V+) -1.1 V to (V+)-0.9 V. In the 200MV transition zone, PSRR, CMRR, offset voltage, offset drift and THD may be reduced compared with the operation outside the area.

Input

The input of the input conclusion range is expanded from (v-)-0.2 v to (V+)+0.2 V. For normal operations, the input should be limited to this range. The absolute maximum input voltage exceeds 500 millivolves. Although the input of the input co -mode but less than the maximum input voltage is invalid, it will not cause any damage to the calculator. Unlike the other inputs shown in the figure, if the current at the input end does not exceed 3 ampel, it may exceed other input terminals.

Under normal circumstances, the input current is 0.5 PA. However, large input (over 500 MV) can cause excess current flow or outflow input pins. Therefore, in addition to maintaining the input voltage below the maximum rated value, the input current must also be limited below 10 mAh. This is easy to use an input voltage resistor to implement, as shown in Figure 4.

AB output level adopts common sourceCrystal pipes are enabled by orbit. The output level can drive 5-k loads between any potential between V+and ground. For light resistance loads ( gt; 100k ), the output voltage can usually swing from the power rail to 18mv. In the case of medium resistance load (10 k to 50 k ), the output voltage can usually swing within the 100 MV range of the power rail, while maintaining a high -opening gain (see typical features ""output voltage swing and output current current "").

The capacity load and stability

OPA2348, which is configured in the unit gain configuration, can directly drive up to 250pf pure capacitor load. Increasing gain can enhance the capacity of the amplifier driver to drive a larger capacitance load (see the typical characteristic ""small signal overwhelming VS 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 5. This greatly reduces the bell, while maintaining the DC performance of pure capacitance load. However, if the resistor load is connected to the capacitor load, the division will be generated, the DC (DC) 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.

In the configuration of the unit gain inverter, the phase margin can be reduced by the capacitor and the gain setting of the resistance at the capacity of the amplifier input terminal, thereby reducing the capacitance Load driver. The best performance can be obtained by using small value resistors. For example, when driving 500 PF loads, the resistance value is reduced from 100 k reduced to 5 k and over -rushing from 55%to 13%(see typical features ""small signal over pumping and load capacitors"") Essence However, when a large value resistance cannot be avoided, a small (4 PF to 6 PF) capacitor CFB can be inserted in the feedback, as shown in Figure 6. The effects of compensating capacitors CIN (including the input capacitance and PC board parasitic capacitor of the amplifier) u200bu200bcan significantly reduce the overwhelming.

OPA2348 Computing amplifier Optimized for driving medium -speed sampling ADC. OPA2348 operational amplifier buffer the ADC input capacitance and the charge generated by this while providing signal gain.

FIG. 7 shows OPA2348 in the basic non -conversion configuration of ADS7822. ADS7822 is a 12-bit, micro-power sampling converter in the MSOP-8 package. When used with the low -power micro -packaging of OPA348, this combination is an ideal choice for limited space and low power consumption applications. In this configuration, the RC network of the ADC input terminal can be used to provide anti -hybrid filteringInject currents and charge injection currents.

OPA2348 can also be used in a limited low -power application to drive the non -reversing configuration of ADS7822.In this configuration, the RC network of the ADC input terminal can be used to provide anti -aliasing filter and charge injection current.As shown in Figure 7, OPA2348 drives ADS7822 in the voice belt filter data collection system.This small low -cost solution provides necessary amplification and signal regulation, and directly with the interface with the polar microphone.The circuit works under VS u003d 2.7V to 5V, and the typical static current is less than 250 μA.