AD8031AR Equivalent & Substitute Parts

Part Overview

The AD8031AR is a voltage feedback amplifier manufactured by Analog Devices Inc., designed as a single-circuit, rail-to-rail operational amplifier in an 8-SOIC surface mount package. This device is classified as obsolete, which necessitates identification of equivalent and substitute components for ongoing design support and production requirements.

The AD8031AR operates across a supply voltage range of 2.7 V to 12 V with an operating temperature range of -40°C to 85°C. Its primary application domain includes general-purpose voltage feedback amplification circuits requiring moderate bandwidth and slew rate performance in compact form factors.

Due to its obsolete status, alternative components must be evaluated to maintain design continuity and ensure component availability for new production runs and legacy system support.

Key Parameters

Parameter	Value	Unit
Amplifier Type	Voltage Feedback	—
Number of Circuits	1	—
Output Type	Rail-to-Rail	—
Slew Rate	35	V/µs
-3dB Bandwidth	80	MHz
Current - Input Bias	450	nA
Voltage - Input Offset	1	mV
Current - Supply	900	µA
Current - Output / Channel	15	mA
Voltage - Supply Span (Min)	2.7	V
Voltage - Supply Span (Max)	12	V
Operating Temperature	-40 to 85	°C
Package / Case	8-SOIC (0.154", 3.90mm Width)	—
Mounting Type	Surface Mount	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the AD8031AR is determined by alignment across the following critical parameters:

Primary Substitution Criteria:

Amplifier Type: Voltage Feedback
Number of Circuits: 1
Output Type: Rail-to-Rail
Package / Case: 8-SOIC form factor
Mounting Type: Surface Mount
Supply Voltage Range: Minimum 2.7 V, Maximum ≥ 12 V
Operating Temperature Range: -40°C to 85°C or broader

Secondary Performance Parameters:

Slew Rate: ≥ 35 V/µs (direct replacement)
-3dB Bandwidth: ≥ 80 MHz (direct replacement)
Current - Output / Channel: ≥ 15 mA (direct replacement)
Current - Supply: ≤ 900 µA (preferred for power budget compatibility)

Substitute parts are grouped into two categories:

Category 1: Direct Equivalents — Parts that maintain identical or superior performance across all critical parameters while preserving the 8-SOIC package and voltage feedback topology.

Category 2: Functional Alternatives — Parts that satisfy core functional requirements (single-circuit, rail-to-rail, 8-SOIC) but may exhibit different performance characteristics in slew rate, bandwidth, or supply current. These alternatives are suitable when performance headroom exists in the application circuit.

Parameter Comparison

Parameter	AD8031AR	AD8031ARZ	ADA4807-1ARJZ-R7	LMH6645MA/NOPB	MC33201VDR2G	MAX4162ESA+T	MC34072DR2G
Manufacturer	Analog Devices	Analog Devices	Analog Devices	National Semiconductor	onsemi	Analog Devices/Maxim	onsemi
Amplifier Type	Voltage Feedback	Voltage Feedback	Voltage Feedback	Voltage Feedback	General Purpose	General Purpose	General Purpose
Number of Circuits	1	1	1	1	1	1	2
Output Type	Rail-to-Rail	Rail-to-Rail	Rail-to-Rail	Push-Pull, Rail-to-Rail	Rail-to-Rail	Rail-to-Rail	Single-Ended
Slew Rate (V/µs)	35	35	225	22	1	0.115	13
-3dB Bandwidth (MHz)	80	80	180	55	—	—	—
Current - Input Bias (nA)	450	450	1200	650	80	0.001	100
Voltage - Input Offset (mV)	1	1	0.14	1	6	0.5	1
Current - Supply (µA)	900	900	1000	725	900	25	1900
Current - Output / Channel (mA)	15	15	80	20	80	15	30
Voltage - Supply Span (Min)	2.7 V	2.7 V	2.7 V	2.5 V	1.8 V	2.7 V	3 V
Voltage - Supply Span (Max)	12 V	12 V	11 V	12 V	12 V	10 V	44 V
Operating Temperature	-40 to 85°C	-40 to 85°C	-40 to 125°C	-40 to 85°C	-55 to 125°C	-40 to 85°C	0 to 70°C
Package / Case	8-SOIC	8-SOIC	SOT-23-6	8-SOIC	8-SOIC	8-SOIC	8-SOIC
Product Status	Obsolete	Active	Active	Active	Active	Active	Active
RoHS Status	—	ROHS3 Compliant	ROHS3 Compliant	—	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Tier 1: Direct Replacement (Recommended)

AD8031ARZ — This part is the active production equivalent of the AD8031AR. It maintains identical electrical specifications across all parameters: 35 V/µs slew rate, 80 MHz bandwidth, 450 nA input bias current, and 900 µA supply current. The AD8031ARZ is ROHS3 compliant and carries active product status with substantial inventory availability (19,526 units). The only difference is packaging format (Tube vs. unspecified for the original), which does not affect electrical performance. This is the primary recommended substitute for direct replacement applications.

Tier 2: Performance-Enhanced Alternatives

ADA4807-1ARJZ-R7 — This Analog Devices part offers superior performance characteristics: 225 V/µs slew rate (6.4× higher), 180 MHz bandwidth (2.25× higher), and 80 mA output current (5.3× higher). However, it is packaged in SOT-23-6 rather than 8-SOIC, requiring PCB layout modification. The ADA4807-1ARJZ-R7 is ROHS3 compliant and active. This substitute is suitable for applications where higher bandwidth and slew rate provide design margin, and PCB redesign is acceptable.

LMH6645MA/NOPB — This National Semiconductor part maintains the 8-SOIC package and voltage feedback topology. It provides 20 mA output current (vs. 15 mA) and operates across the same supply range (2.5 V to 12 V). However, slew rate is reduced to 22 V/µs (63% of original) and bandwidth is 55 MHz (69% of original). This substitute is applicable only when the application circuit has sufficient performance margin to tolerate reduced slew rate and bandwidth.

Tier 3: Functional Alternatives (Limited Compatibility)

MC33201VDR2G — This onsemi part is a general-purpose amplifier (not voltage feedback topology) in 8-SOIC package with rail-to-rail output. It offers extended temperature range (-55°C to 125°C) and lower minimum supply voltage (1.8 V). However, slew rate is severely reduced to 1 V/µs (2.9% of original), and input offset voltage is 6 mV (6× higher). This part is suitable only for low-frequency applications where the reduced performance is acceptable.

MAX4162ESA+T — This Analog Devices/Maxim part is a general-purpose amplifier in 8-SOIC package with extremely low supply current (25 µA). However, slew rate is 0.115 V/µs (0.3% of original) and bandwidth is 200 kHz (0.25% of original). Input bias current is negligible (1 pA). This part is suitable only for ultra-low-power, low-frequency applications and is not recommended for bandwidth-critical designs.

MC34072DR2G — This onsemi part is a dual-channel general-purpose amplifier in 8-SOIC package. It provides higher output current (30 mA per channel) and extended supply voltage range (3 V to 44 V). However, it contains two circuits (not one), slew rate is 13 V/µs (37% of original), and operating temperature range is limited to 0°C to 70°C. This part is not suitable as a direct substitute due to circuit count mismatch and reduced temperature range.

Selection Criteria Summary:

For direct replacement in existing designs: Use AD8031ARZ
For designs requiring higher performance and accepting package change: Use ADA4807-1ARJZ-R7
For low-frequency applications with performance margin: Use LMH6645MA/NOPB
For ultra-low-power applications: Use MAX4162ESA+T
For applications requiring extended supply voltage range: Use MC34072DR2G (with circuit count consideration)

All recommended substitutes maintain ROHS3 compliance and MSL 1 (Unlimited) moisture sensitivity rating, ensuring compatibility with standard manufacturing processes.

Frequently Asked Questions (FAQ)

Q1: Can AD8031ARZ be used as a direct drop-in replacement for AD8031AR?

A: Yes. The AD8031ARZ is electrically identical to the AD8031AR across all specified parameters: slew rate (35 V/µs), bandwidth (80 MHz), input bias current (450 nA), supply current (900 µA), and output current (15 mA). Both operate across 2.7 V to 12 V supply range and -40°C to 85°C temperature range. The only difference is packaging format (Tube vs. unspecified). No circuit modifications are required.

Q2: Why is the ADA4807-1ARJZ-R7 listed as a substitute if it uses a different package (SOT-23-6 vs. 8-SOIC)?

A: The ADA4807-1ARJZ-R7 is included as a performance-enhanced alternative for applications where PCB redesign is feasible. It offers superior electrical performance (225 V/µs slew rate, 180 MHz bandwidth, 80 mA output current) while maintaining voltage feedback topology and rail-to-rail output. The package change requires PCB layout modification but enables higher-performance designs. This substitute is recommended only when performance margin justifies redesign effort.

Q3: What is the difference between "Voltage Feedback" and "General Purpose" amplifier classifications?

A: Voltage feedback amplifiers are optimized for stable operation with external feedback networks and are designed for precise gain and bandwidth control. General-purpose amplifiers offer broader application flexibility but may have different frequency response and stability characteristics. The AD8031AR is a voltage feedback device; general-purpose substitutes (MAX4162ESA+T, MC33201VDR2G) may require different compensation networks and are not direct functional equivalents.

Q4: Can I use MAX4162ESA+T as a substitute for high-frequency applications?

A: No. The MAX4162ESA+T has a gain-bandwidth product of only 200 kHz and slew rate of 0.115 V/µs, making it unsuitable for the 80 MHz bandwidth and 35 V/µs slew rate requirements of the AD8031AR. This part is designed for ultra-low-power, low-frequency applications only. For high-frequency requirements, use AD8031ARZ or ADA4807-1ARJZ-R7.

Q5: What does "Rail-to-Rail" output mean, and why is it important for substitution?

A: Rail-to-rail output capability means the amplifier output can swing to within a small margin of both positive and negative supply rails. This maximizes the usable output voltage range and is critical for low-supply-voltage applications. The AD8031AR and most recommended substitutes (AD8031ARZ, ADA4807-1ARJZ-R7, LMH6645MA/NOPB, MC33201VDR2G, MAX4162ESA+T) all feature rail-to-rail output, ensuring compatibility in this regard.

Q6: Why is MC34072DR2G not recommended as a direct substitute despite being in 8-SOIC package?

A: The MC34072DR2G contains two amplifier circuits, whereas the AD8031AR contains one. Additionally, it has single-ended output (not rail-to-rail), reduced slew rate (13 V/µs vs. 35 V/µs), and limited operating temperature range (0°C to 70°C vs. -40°C to 85°C). While it shares the 8-SOIC package, these functional differences make it unsuitable for direct substitution.

Q7: Are all substitute parts ROHS3 compliant?

A: All active substitute parts listed (AD8031ARZ, ADA4807-1ARJZ-R7, MC33201VDR2G, MAX4162ESA+T, MC34072DR2G) are ROHS3 compliant. The LMH6645MA/NOPB does not specify RoHS status in the provided data. All parts maintain MSL 1 (Unlimited) moisture sensitivity rating, compatible with standard surface mount assembly processes.

Q8: What is the significance of "Product Status: Obsolete" for the AD8031AR?

A: Obsolete status indicates the part is no longer in active production and will eventually become unavailable. This necessitates transition to an active equivalent (AD8031ARZ) for new designs and ongoing production support. Existing inventory of AD8031AR may be available from distributors, but long-term availability cannot be guaranteed. AD8031ARZ is the recommended transition path.

Q9: Can I substitute multiple parts from the list interchangeably in the same design?

A: No. Each substitute has different electrical characteristics. Interchangeability depends on application-specific performance requirements. AD8031ARZ is the only true drop-in replacement. Other substitutes require circuit analysis to confirm compatibility with slew rate, bandwidth, and output current requirements. Mixing different substitutes in the same design is not recommended without detailed performance verification.

Q10: What should I consider when selecting between AD8031ARZ and ADA4807-1ARJZ-R7?

A: Choose AD8031ARZ for direct replacement with no PCB changes required. Choose ADA4807-1ARJZ-R7 only if your application requires higher bandwidth (180 MHz vs. 80 MHz), higher slew rate (225 V/µs vs. 35 V/µs), or higher output current (80 mA vs. 15 mA), and you can accommodate the SOT-23-6 package change and PCB redesign. The ADA4807-1ARJZ-R7 also supports extended operating temperature (-40°C to 125°C vs. -40°C to 85°C).

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