OP285GS Equivalent & Substitute Parts

Part Overview

The OP285GS is a J-FET input operational amplifier manufactured by Analog Devices Inc., configured as a dual-circuit device in 8-SOIC surface mount packaging. This component is classified as obsolete, indicating that direct procurement of the OP285GS may face supply constraints. The OP285GS delivers high input impedance and low input bias current characteristics suitable for precision signal conditioning applications. Identification of equivalent and substitute parts is necessary to maintain design continuity and ensure component availability for production and repair applications.

Key Parameters

Parameter	Value	Unit
Amplifier Type	J-FET	—
Number of Circuits	2	—
Slew Rate	22	V/µs
Gain Bandwidth Product	9	MHz
Current - Input Bias	100	nA
Voltage - Input Offset	35	µV
Current - Supply	4	mA
Voltage - Supply Span (Min)	9	V
Voltage - Supply Span (Max)	44	V
Operating Temperature Range	-40 to 85	°C
Package / Case	8-SOIC (0.154", 3.90mm Width)	—
Mounting Type	Surface Mount	—
Moisture Sensitivity Level	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the OP285GS is determined by compatibility across the following critical parameters: amplifier type, number of circuits, package form factor, mounting type, and electrical performance envelope defined by slew rate, gain bandwidth product, input bias current, input offset voltage, supply current, and supply voltage range.

The OP285GS is a J-FET input amplifier. Direct equivalents maintain J-FET input architecture. The OP285GSZ represents a direct equivalent with identical electrical specifications and packaging, differentiated only by packaging format (tube versus cut tape) and active product status.

General-purpose amplifiers (ADA4075-2ARZ, LT1124CS8#TR, MC4558CDT, MC4558IDT, MC1458DT, OPA2277MDTEP, TJM4558CDT) and audio amplifiers (LME49860MAX/NOPB) provide functional substitution when J-FET input characteristics are not mandatory. These alternatives operate within the 8-SOIC package envelope and support the required supply voltage range. Selection among these alternatives depends on specific application requirements for slew rate, bandwidth, input bias current, and operating temperature range.

The NCS20032DMR2G operates in an 8-MSOP package, which differs from the 8-SOIC form factor and is therefore suitable only when board layout permits package substitution.

Parameter Comparison

Parameter	OP285GS	OP285GSZ	ADA4075-2ARZ	LT1124CS8#TR	LME49860MAX/NOPB	MC4558CDT	MC4558IDT	TJM4558CDT	OPA2277MDTEP
Amplifier Type	J-FET	J-FET	General Purpose	General Purpose	Audio	General Purpose	General Purpose	General Purpose	General Purpose
Number of Circuits	2	2	2	2	2	2	2	2	2
Slew Rate (V/µs)	22	22	12	4.5	20	2.2	2.2	2.2	0.8
Gain Bandwidth Product (MHz)	9	9	6.5	12.5	55	5.5	5.5	5.5	1
Current - Input Bias (nA)	100	100	30	7	10	50	50	50	0.5
Voltage - Input Offset (µV)	35	35	200	25	140	1000	1000	1000	20
Current - Supply (mA)	4	4	1.8 (x2)	2.3 (x2)	10.5 (x2)	2.3	2.3	2.3	0.79 (x2)
Voltage - Supply Span Min (V)	9	9	9	8	5	4	4	44	4
Voltage - Supply Span Max (V)	44	44	36	44	44	40	40	44	36
Operating Temperature (°C)	-40 to 85	-40 to 85	-40 to 125	0 to 70	-40 to 85	0 to 70	-40 to 105	0 to 70	-55 to 125
Package / Case	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC
Product Status	Obsolete	Active	Active	Active	Active	Active	Active	Active	Active
RoHS Status	—	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Direct Equivalent (Preferred for Obsolete Part Replacement)

OP285GSZ is the primary substitute for OP285GS. Both components are manufactured by Analog Devices Inc. and share identical electrical specifications, J-FET input architecture, and 8-SOIC packaging. The OP285GSZ maintains active product status and is ROHS3 compliant, ensuring long-term availability and regulatory compliance. The distinction between OP285GS and OP285GSZ is packaging format: OP285GS is supplied in cut tape format, while OP285GSZ is supplied in tube format. This substitution requires no circuit redesign.

Functional Alternatives for General-Purpose Applications

When J-FET input characteristics are not critical to application performance, the following active alternatives provide functional substitution within the 8-SOIC package:

MC4558CDT and MC4558IDT (STMicroelectronics) offer the lowest cost alternative with 5.5 MHz bandwidth and 2.2 V/µs slew rate. MC4558IDT extends the operating temperature range to -40°C to 105°C, suitable for extended temperature applications. Both are ROHS3 compliant with unlimited moisture sensitivity.

LT1124CS8#TR (Analog Devices Inc.) provides 12.5 MHz bandwidth and 4.5 V/µs slew rate with 7 nA input bias current, approaching J-FET performance characteristics. Operating temperature range is 0°C to 70°C.

ADA4075-2ARZ (Analog Devices Inc.) operates within the iPolar® series with 6.5 MHz bandwidth and 12 V/µs slew rate. Operating temperature extends to 125°C. Supply voltage maximum is limited to 36 V.

LME49860MAX/NOPB (Texas Instruments) is an audio amplifier with 55 MHz bandwidth and 20 V/µs slew rate, suitable for high-frequency signal conditioning. Supply voltage minimum is 5 V.

OPA2277MDTEP (Texas Instruments) provides the lowest input offset voltage (20 µV) and lowest input bias current (500 pA) among general-purpose alternatives, with extended operating temperature range (-55°C to 125°C). Slew rate is 0.8 V/µs and bandwidth is 1 MHz.

Package Variant Consideration

NCS20032DMR2G (onsemi) operates in 8-MSOP packaging, which differs from the 8-SOIC form factor. This component is suitable only when board layout permits package substitution. It features rail-to-rail output, extremely low input bias current (1 pA), and operates across 1.7 V to 5.5 V supply range.

Frequently Asked Questions (FAQ)

Q: Can OP285GSZ be used as a direct replacement for OP285GS without circuit modification?

A: Yes. OP285GSZ is electrically and functionally identical to OP285GS. Both components feature J-FET input architecture, identical slew rate (22 V/µs), gain bandwidth product (9 MHz), input bias current (100 nA), and input offset voltage (35 µV). The only difference is packaging format: OP285GS is supplied in cut tape, while OP285GSZ is supplied in tube. No circuit redesign is required.

Q: What is the primary reason to substitute OP285GS with an alternative part?

A: OP285GS is classified as obsolete, which creates supply chain risk. OP285GSZ provides the same electrical performance with active product status. General-purpose alternatives (MC4558CDT, MC4558IDT, LT1124CS8#TR, ADA4075-2ARZ) are suitable when J-FET input characteristics are not mandatory for application performance.

Q: How do I determine which substitute part is appropriate for my application?

A: Evaluate the following criteria in order of priority: (1) Required input bias current—if less than 100 nA is mandatory, J-FET input (OP285GSZ) or ultra-low bias alternatives (OPA2277MDTEP with 500 pA) are necessary; (2) Required slew rate and bandwidth—if greater than 22 V/µs or 9 MHz is required, LME49860MAX/NOPB (20 V/µs, 55 MHz) is suitable; (3) Operating temperature range—if extended temperature operation is required, select MC4558IDT (-40°C to 105°C), ADA4075-2ARZ (-40°C to 125°C), or OPA2277MDTEP (-55°C to 125°C); (4) Supply voltage constraints—verify minimum and maximum supply voltage compatibility with your power supply design.

Q: Are all substitute parts ROHS3 compliant?

A: All active substitute parts listed are ROHS3 compliant. OP285GS (obsolete) does not specify RoHS status. OP285GSZ, ADA4075-2ARZ, LT1124CS8#TR, LME49860MAX/NOPB, MC4558CDT, MC4558IDT, TJM4558CDT, OPA2277MDTEP, and NCS20032DMR2G are all ROHS3 compliant.

Q: Can I use NCS20032DMR2G as a substitute if my board layout permits package changes?

A: NCS20032DMR2G operates in 8-MSOP packaging, which is physically different from the 8-SOIC package of OP285GS. This component is suitable only if your PCB layout can accommodate the 8-MSOP form factor. NCS20032DMR2G features rail-to-rail output, extremely low input bias current (1 pA), and operates across a narrower supply range (1.7 V to 5.5 V). Verify that your application supply voltage is compatible before selecting this alternative.

Q: What is the difference between MC4558CDT and MC4558IDT?

A: MC4558CDT and MC4558IDT are both general-purpose dual operational amplifiers with identical electrical specifications (5.5 MHz bandwidth, 2.2 V/µs slew rate, 50 nA input bias current). The primary difference is operating temperature range: MC4558CDT operates from 0°C to 70°C, while MC4558IDT operates from -40°C to 105°C. Select MC4558IDT for extended temperature applications.

Q: Is input offset voltage critical for my application?

A: Input offset voltage becomes critical in precision signal conditioning, instrumentation, and low-level signal detection applications. OP285GS specifies 35 µV offset voltage. Alternatives with comparable offset voltage include LT1124CS8#TR (25 µV) and OPA2277MDTEP (20 µV). General-purpose alternatives (MC4558CDT, MC4558IDT, TJM4558CDT) specify 1 mV offset voltage, which is acceptable for many applications but unsuitable for precision measurement circuits.

Q: What is the moisture sensitivity level, and why does it matter?

A: Moisture Sensitivity Level (MSL) indicates the component's susceptibility to moisture absorption during storage and handling. MSL 1 (unlimited) means the component has no moisture sensitivity restrictions and can be stored indefinitely without special precautions. All listed substitute parts are MSL 1 compliant, except OPA2277MDTEP, which is MSL 3 (168 hours), requiring controlled storage conditions and baking before reflow soldering.

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