ADA4661-2ARMZ Bridge Rectifiers

Technical Specifications of ADA4661-2ARMZ

Datasheet	ADA4661-2ARMZ datasheet
Category	Integrated Circuits (ICs)
Family	Linear – Amplifiers – Instrumentation, OP Amps, Buffer Amps
Manufacturer	Analog Devices Inc.
Series	–
Packaging	Tube
Part Status	Active
Amplifier Type	General Purpose
Number of Circuits	2
Output Type	Rail-to-Rail
Slew Rate	2 V/μs
Gain Bandwidth Product	4MHz
-3db Bandwidth	2.1MHz
Current – Input Bias	0.5pA
Voltage – Input Offset	30μV
Current – Supply	630μA
Current – Output / Channel	220mA
Voltage – Supply, Single/Dual (±)	3 V ~ 18 V, ±1.5 V ~ 9 V
Operating Temperature	-40°C ~ 125°C
Mounting Type	Surface Mount
Package / Case	8-TSSOP, 8-MSOP (0.118″, 3.00mm Width)
Supplier Device Package	8-MSOP

ADA4661-2ARMZ Description

Welcome to Analog Devices’ powerful and versatile general-purpose amplifier, the ADA4661-2ARMZ. Featuring two supply voltage options and a temperature range of -40°C to 125°C, the ADA4661-2ARMZ OP amp is popular for signal processing circuits. It’s cost-effective and efficient due to its CMOS technology and two channels per chip.

This tutorial will explain the ADA4661-characteristics 2ARMZ’s and capabilities. Whether you are an experienced engineer or starting out, this article will help you build circuits. Let’s learn about the ADA4661-2ARMZ!

General Description

The ADA4661-2 is a dual precision rail-to-rail input/output amplifier designed for use in systems requiring low power, high bandwidth, and a wide variety of supply voltages. ADA4661-2 is supported by 3.0 V, 10 V, and 18 V power supplies. Dual supplies of 2.5 V, 3.3 V, and 5 V, as well as single supplies of 3.3 V, 5 V, 10 V, 12 V, and 15 V, all operate properly. Offset voltage can be minimized with DigiTrim® trimming from Analog Devices, Inc. The ADA4661-cutting-edge 2’s architecture allows it to reject a wide range of common-mode voltages from VSY + 1.5 V to +VSY 1.5 V with a negligible offset voltage. The 8-lead MSOP and LFCSP (3 mm) ADA4661-2 are required for use over a wider range of temperatures in industrial settings.

ADA4661-2ARMZ FEATURES

A maximum current draw of 725 A is achieved at a high voltage (18 V).

Reduced voltage offset.

150 µV maximum at VSY/2.

300 µV maximum over the entire common-mode range.

Input bias current as low as 15 pA.

Bandwidth product of the gain: typically, around 4 MHz when AV is set to 100.

3 V to 18 V for single-supply operation.

Operation using two supplies: 1.5 to 9 volts.

Unity increase is steady.

ADA4661-2ARMZ Applications

• Current shunt monitors.
• Active filters.
• Portable medical equipment.
• Buffer/level shifting.
• Battery powered instrumentation

Applications Information

The ADA4661-2 is a precision CMOS amplifier with a low supply voltage need (between 3 V and 18 V) and rail-to-rail input and output. A higher level of accuracy than is possible with standard CMOS amplifiers is achieved by employing Analog Devices’ DigiTrim technology in this amplifier.

The DigiTrim approach is used to fine-tune the offset voltage of an amplifier after it has been assembled. Post-packaging trimming improves performance by compensating for voltage discrepancies brought on by mechanical strains during assembly. The ADA4661-2 employs specialized input and output stages to realize a rail-to-rail input and output range on a low-current source.

● Gain Stage

The amplifier’s second stage consists of a folded-cascade transistor and an NPN differential pair (Q1, Q2) (M13 to M20). Nested Miller compensation is a characteristic of the amplifier (C1 to C3).

● Output Stage

The M21 and M22 transistors provide a complementary output stage in the ADA4661-2. The V1 voltage is used to bias these transistors in a Class AB topology configuration. Using this topology, we can have a rail-to-rail output swing, with the voltage on the output coming within millivolts of the source rails. Since these transistors are low RON MOS devices, their output impedance sets a cap on the maximum voltage that can be generated. Output voltage swing can be evaluated by plotting supply rail voltage versus load current. Due to the ADA4661-2 output stage’s high voltage and current capabilities, the user must keep the device within the thermally safe operating region.

● EMI Rejection Ratio

High-frequency electromagnetic interference is a common cause of circuit malfunction (EMI). It is essential that an op-amp accurately amplifies input signals when signal strength is low, and transmission lines are lengthy. Electromagnetic interference (EMI) can affect any op amp’s pins, including the inverting input, noninverting input, positive supply, negative supply, and output. The op-amp receives these high-frequency impulses via various coupling methods, including direct contact, near-field, and far-field radiation.

Antennas can pick up high-frequency electromagnetic interference (EMI) signals in wires and PCB traces. Because of the limited bandwidth of most amplifiers, RF and EMI signals are not amplified by them. However, op-amps can rectify these out-of-band signals because of the nonlinearities of the input devices. This dc offset is produced when high-frequency signals are corrected.

● Current Shunt Monitor

Detecting signals close to the positive or negative rail is necessary for many applications. One such use is current shunt monitors, which find widespread use in feedback control systems. Additionally, they find utility in power metering, battery fuel gauging, and feedback controls for electrical power steering, amongst other places. A shunt with low resistance is preferred in this situation because it reduces the voltage lost in series. This reduces power consumption and makes it possible to measure high currents with minimal environmental impact. The ADA4661-2 is a high-quality amplifier ideal for precise current monitoring thanks to its low input bias current, low offset voltage, and rail-to-rail functionality.

● Capacitive Load Drive

Capacitive loads of up to 50 pF can be driven without issue by the ADA4661-2 in any arrangement. Overshoot, ringing, and oscillation are all possible outcomes when driving capacitive loads bigger than the amplifier’s specifications allow. Heavy capacitive load causes the amplifier’s frequency response to peak and decreases the phase margin. In the time domain, peaking is the same as overshooting or ringing. Therefore, external compensation should be applied if the ADA4661-2 must drive a load greater than 50 pF. The unity-gain arrangement is the most unstable; therefore, this adjustment is crucial.

● Considering Noise from High-Impedance Sources

When a high-impedance source operates an amplifier, current noise at the input terminals might dominate the overall circuit noise. CMOS amplifiers, such as the ADA4661-2, do not have a shot noise source built into the input terminals as bipolar amplifiers. The ESD protection diodes’ reverse saturation current is responsible for minimal shot noise. The normal range for this induced current noise is between 1 fA/Hz and 10 fA/Hz. Therefore, a large source impedance greater than 10 G is necessary to measure current noise in this range.  The effect known as blowback noise is where the ADA4661-2 shines in debate.

The blowback effect originates from the noise in the amplifier’s tail current source, which is capacitively connected to the amplifier inputs via the input transistors’ gate-to-source capacitance (CGS). Because of the source’s impedance, this blowback noise is amplified and manifests as voltage noise at the input terminal.

For every 10 increases in source impedance, there will be a corresponding 10 increases in voltage noise caused by blowback. The CGS coupling attenuates low-frequency components of the blowback noise spectrum, creating a high-pass response. Both parasitic capacitances at the tail current source and on the PCB contribute to a double-pole roll-off in the spectrum at very high frequencies.

Conclusion

Analog Devices’ ADA4661-2ARMZ operational amplifier (OP amp) is, in short, an excellent choice for a wide variety of signal processing applications. This device’s wide temperature range of -40 degrees Celsius to 125 degrees Celsius and a large selection of dual supply voltage options make it useful in many contexts. Its CMOS design and dual-channel implementation per chip also make it a reasonable pick for your circuit. Order from ICRFQ, the best Chinese electronics distributor, to get the most out of this versatile amplifier. Quickly improve the performance of your signal processing circuit by making the necessary improvements now.

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