ISL28478FAZ Equivalent & Substitute Parts

Part Overview

The ISL28478FAZ is a general-purpose operational amplifier manufactured by Renesas Electronics Corporation, configured as a 4-circuit rail-to-rail amplifier in a 16-QSOP surface mount package. This device is classified as obsolete, necessitating identification of functionally equivalent substitute components for ongoing design support and production continuity. The ISL28478FAZ operates across a supply voltage range of 2.4 V to 5.5 V with an operating temperature range of -40°C to 125°C, making it suitable for industrial and extended-temperature applications.

Key Parameters

Parameter	Value
Manufacturer Part Number	ISL28478FAZ
Manufacturer	Renesas Electronics Corporation
Category	Linear, Amplifiers
Product Status	Obsolete
Amplifier Type	General Purpose
Number of Circuits	4
Output Type	Rail-to-Rail
Package / Case	16-SSOP (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Voltage - Supply Span (Min)	2.4 V
Voltage - Supply Span (Max)	5.5 V
Operating Temperature	-40°C ~ 125°C
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	2 (1 Year)

Substitute Part Grouping Explanation

Substitution of the ISL28478FAZ is determined by the following critical parameters:

Functional Equivalence Criteria:

Number of circuits: 4 channels required
Output type: Rail-to-rail configuration
Package compatibility: 16-SSOP surface mount form factor
Supply voltage range: Minimum 2.4 V to 5.5 V maximum
Operating temperature range: Extended range -40°C to 125°C preferred for industrial applications

Substitute Categories:

The identified substitute parts fall into two distinct groups based on amplifier technology and performance characteristics:

Group 1: LTC6085 Series (Analog Devices Inc.)

LTC6085CGN#PBF (Tube packaging)
LTC6085CGN#TRPBF (Tape & Reel packaging)
LTC6085HGN#PBF (Tube packaging, extended temperature)
LTC6085HGN#TRPBF (Tape & Reel packaging, extended temperature)

These CMOS amplifiers provide lower input bias current and reduced supply current compared to the ISL28478FAZ. The LTC6085HGN variants support the full -40°C to 125°C temperature range, matching the original part's thermal specifications.

Group 2: OPA4340 Series (Texas Instruments)

OPA4340EA/250 (Cut Tape & Digi-Reel packaging)
OPA4340EA/2K5 (Cut Tape & Digi-Reel packaging)

These microPOWER CMOS amplifiers offer enhanced slew rate and gain bandwidth product performance. Both variants operate across -40°C to 85°C, providing partial temperature range coverage.

All substitute parts maintain 16-SSOP package compatibility, ROHS3 compliance, and rail-to-rail output configuration.

Parameter Comparison

Parameter	ISL28478FAZ	LTC6085CGN#PBF	LTC6085CGN#TRPBF	LTC6085HGN#PBF	LTC6085HGN#TRPBF	OPA4340EA/250	OPA4340EA/2K5
Manufacturer	Renesas	Analog Devices	Analog Devices	Analog Devices	Analog Devices	Texas Instruments	Texas Instruments
Product Status	Obsolete	Active	Active	Active	Active	Active	Active
Amplifier Type	General Purpose	CMOS	CMOS	CMOS	CMOS	CMOS	CMOS
Number of Circuits	4	4	4	4	4	4	4
Output Type	Rail-to-Rail	Rail-to-Rail	Rail-to-Rail	Rail-to-Rail	Rail-to-Rail	Rail-to-Rail	Rail-to-Rail
Slew Rate	0.15 V/µs	0.5 V/µs	0.5 V/µs	0.5 V/µs	0.5 V/µs	6 V/µs	6 V/µs
Gain Bandwidth Product	300 kHz	1.5 MHz	1.5 MHz	1.5 MHz	1.5 MHz	5.5 MHz	5.5 MHz
Current - Input Bias	10 pA	1 pA	1 pA	1 pA	1 pA	0.2 pA	0.2 pA
Voltage - Input Offset	0.2 µV	300 µV	300 µV	300 µV	300 µV	150 µV	150 µV
Current - Supply (x4 Channels)	240 µA	110 µA	110 µA	110 µA	110 µA	750 µA	750 µA
Current - Output / Channel	31 mA	12.5 mA	12.5 mA	12.5 mA	12.5 mA	50 mA	50 mA
Voltage - Supply Span (Min)	2.4 V	2.5 V	2.5 V	2.5 V	2.5 V	2.5 V	2.5 V
Voltage - Supply Span (Max)	5.5 V	5.5 V	5.5 V	5.5 V	5.5 V	5.5 V	5.5 V
Operating Temperature	-40°C ~ 125°C	0°C ~ 70°C	0°C ~ 70°C	-40°C ~ 125°C	-40°C ~ 125°C	-40°C ~ 85°C	-40°C ~ 85°C
Package / Case	16-SSOP (0.154", 3.90mm Width)	16-SSOP (0.154", 3.90mm Width)	16-SSOP (0.154", 3.90mm Width)	16-SSOP (0.154", 3.90mm Width)	16-SSOP (0.154", 3.90mm Width)	16-SSOP (0.154", 3.90mm Width)	16-SSOP (0.154", 3.90mm Width)
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	2 (1 Year)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	2 (1 Year)	2 (1 Year)

Engineering Selection Recommendations

For Full Temperature Range Compatibility (-40°C to 125°C):

The LTC6085HGN#PBF and LTC6085HGN#TRPBF are the primary substitutes when the complete operating temperature range of the ISL28478FAZ must be maintained. Both variants are active products from Analog Devices Inc., ensuring long-term availability and support. The LTC6085HGN#TRPBF offers the advantage of tape and reel packaging for automated assembly processes. These devices provide superior input bias current performance (1 pA versus 10 pA) and reduced supply current consumption (110 µA versus 240 µA), while maintaining electrical compatibility through identical 16-SSOP packaging and rail-to-rail output configuration.

For Applications with Reduced Temperature Requirements (0°C to 70°C):

The LTC6085CGN#PBF and LTC6085CGN#TRPBF are suitable for applications operating within the 0°C to 70°C range. These variants offer the same electrical performance as the HGN series with improved moisture sensitivity characteristics (MSL 1 versus MSL 2), reducing handling and storage requirements.

For Enhanced Performance Requirements:

The OPA4340EA/250 and OPA4340EA/2K5 from Texas Instruments provide significantly improved dynamic performance with 6 V/µs slew rate and 5.5 MHz gain bandwidth product, compared to the ISL28478FAZ specifications of 0.15 V/µs and 300 kHz. These devices are suitable for applications requiring higher-speed signal processing. However, the maximum operating temperature is limited to 85°C, which does not cover the full industrial temperature range of the original part. Both OPA4340 variants are active products with ROHS3 compliance.

Compliance and Regulatory Status:

All substitute parts maintain ROHS3 compliance and REACH unaffected status, consistent with the original ISL28478FAZ. Moisture sensitivity levels vary between MSL 1 and MSL 2, affecting storage and handling protocols.

Frequently Asked Questions (FAQ)

Q: Can the LTC6085 series directly replace the ISL28478FAZ in existing designs?

A: The LTC6085 series provides functional equivalence through identical 4-circuit rail-to-rail configuration in 16-SSOP packaging. However, circuit performance will differ due to variations in slew rate, gain bandwidth product, and input offset voltage. The LTC6085HGN variants support the full -40°C to 125°C temperature range of the original part. Electrical characterization of the specific application is required to confirm compatibility.

Q: What is the primary difference between LTC6085CGN and LTC6085HGN variants?

A: The LTC6085CGN operates across 0°C to 70°C, while the LTC6085HGN extends to -40°C to 125°C. All other electrical parameters are identical. For industrial and extended-temperature applications, the LTC6085HGN is the appropriate selection.

Q: Are the OPA4340EA variants suitable for industrial temperature applications?

A: The OPA4340EA/250 and OPA4340EA/2K5 operate across -40°C to 85°C, which covers the lower temperature extreme but does not extend to the 125°C maximum of the ISL28478FAZ. These devices are suitable for applications with maximum operating temperatures of 85°C or lower.

Q: What packaging options are available for the substitute parts?

A: The LTC6085 series is available in tube packaging (PBF suffix) and tape & reel packaging (TRPBF suffix). The OPA4340EA variants are supplied in cut tape and Digi-Reel packaging. All maintain the 16-SSOP form factor. Tape & reel packaging is recommended for high-volume automated assembly processes.

Q: How do the supply current specifications compare?

A: The ISL28478FAZ draws 240 µA across four channels. The LTC6085 series reduces this to 110 µA, providing 54% lower power consumption. The OPA4340EA series draws 750 µA, representing higher power consumption. For battery-powered or power-constrained applications, the LTC6085 series is preferred.

Q: What is the significance of the MSL rating difference?

A: The ISL28478FAZ and OPA4340EA variants carry MSL 2 (1 Year), requiring storage at controlled humidity and shelf-life management. The LTC6085 series carries MSL 1 (Unlimited), eliminating moisture sensitivity constraints and reducing handling complexity during manufacturing and storage.

Q: Are all substitute parts ROHS3 compliant?

A: Yes, all identified substitute parts maintain ROHS3 compliance, consistent with the original ISL28478FAZ. All parts are REACH unaffected.

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