LF347MX Equivalent & Substitute Parts

Part Overview

The LF347MX is a J-FET operational amplifier integrated circuit manufactured by onsemi, configured as a 4-circuit device in a 14-SOP surface mount package. This component is classified as obsolete, which necessitates identification of equivalent and substitute parts for ongoing design requirements and production continuity. The LF347MX operates across a supply voltage range of 7V to 36V with a slew rate of 13V/µs and a gain bandwidth product of 4 MHz, making it suitable for applications requiring low input bias current and moderate bandwidth performance.

Key Parameters

Parameter	Value
Manufacturer Part Number	LF347MX
Manufacturer	onsemi
Amplifier Type	J-FET
Number of Circuits	4
Slew Rate	13V/µs
Gain Bandwidth Product	4 MHz
Current - Input Bias	50 pA
Voltage - Input Offset	5 mV
Current - Supply	7.2 mA (x4 Channels)
Current - Output / Channel	40 mA
Voltage - Supply Span (Min)	7 V
Voltage - Supply Span (Max)	36 V
Operating Temperature	0°C ~ 70°C
Package / Case	14-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Product Status	Obsolete
Moisture Sensitivity Level (MSL)	1 (Unlimited)
REACH Status	REACH Unaffected

Substitute Part Grouping Explanation

Substitution of the LF347MX is determined by strict adherence to the following electrical and mechanical parameters:

Primary Substitution Criteria:

Amplifier Type: J-FET configuration
Number of Circuits: 4 operational amplifiers per package
Package / Case: 14-SOIC (0.154", 3.90mm Width) physical compatibility
Mounting Type: Surface Mount
Slew Rate: 13V/µs or greater
Gain Bandwidth Product: 3 MHz or greater
Current - Input Bias: 50 pA or lower
Voltage - Supply Span: Minimum 7V, Maximum 36V or greater
Operating Temperature: 0°C ~ 70°C or extended range
Current - Output / Channel: 31 mA or greater

Secondary Compatibility Factors:

Moisture Sensitivity Level: MSL 1 (Unlimited)
REACH Status: REACH Unaffected
Surface mount package compatibility

Substitute parts are grouped based on whether they meet all primary criteria for direct replacement or whether they offer enhanced performance characteristics while maintaining functional compatibility.

Parameter Comparison

Parameter	LF347MX (onsemi)	LF347DR (TI)	LF347BDR (TI)	LF347D (STM)	LF347DT (STM)	LF347MX/NOPB (TI)
Amplifier Type	J-FET	J-FET	J-FET	J-FET	J-FET	J-FET
Number of Circuits	4	4	4	4	4	4
Slew Rate (V/µs)	13	13	13	16	16	13
Gain Bandwidth Product (MHz)	4	3	3	3	4	4
Current - Input Bias (pA)	50	50	50	20	20	50
Voltage - Input Offset (mV)	5	5	3	3	3	5
Current - Supply (mA x4 Channels)	7.2	8	8	1.4	1.4	7.2
Current - Output / Channel (mA)	40	40	31	40	40	Not Specified
Voltage - Supply Span (Min)	7 V	7 V	7 V	44 V	44 V	10 V
Voltage - Supply Span (Max)	36 V	36 V	36 V	44 V	44 V	36 V
Operating Temperature	0°C ~ 70°C	0°C ~ 70°C	0°C ~ 70°C	0°C ~ 70°C	0°C ~ 70°C	0°C ~ 70°C
Package / Case	14-SOIC	14-SOIC	14-SOIC	14-SOIC	14-SOIC	14-SOIC
Product Status	Obsolete	Active	Active	Active	Active	Active
RoHS Status	Not Specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1	1	1	1	1	1
REACH Status	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected

Engineering Selection Recommendations

Direct Replacement Candidates (Highest Compatibility):

The LF347DR (Texas Instruments) and LF347MX/NOPB (Texas Instruments) are the primary direct replacement options for the obsolete LF347MX. Both parts maintain identical electrical specifications including slew rate (13V/µs), gain bandwidth product (4 MHz), input bias current (50 pA), and supply voltage range (7V to 36V). Both are currently in active product status with ROHS3 compliance and unlimited moisture sensitivity rating. The LF347DR is available in Cut Tape (CT) & Digi-Reel® packaging with 105,200 units in stock, while the LF347MX/NOPB is available in the same packaging format with 25,200 units in stock.

Secondary Replacement Options (Enhanced Performance):

The LF347DT (STMicroelectronics) offers improved electrical characteristics with a higher slew rate (16V/µs), lower input bias current (20 pA), and lower input offset voltage (3 mV) compared to the original LF347MX. This part is active and ROHS3 compliant with 27,321 units in stock. However, the supply voltage span specification differs (44V minimum and maximum), which may require circuit design verification for applications utilizing the full 7V to 36V range of the original part.

The LF347BDR (Texas Instruments) maintains electrical compatibility with the LF347MX but exhibits slightly lower output current per channel (31 mA versus 40 mA) and higher supply current (8 mA versus 7.2 mA). This part is active and ROHS3 compliant with 4,007 units in stock.

Not Recommended for Direct Substitution:

The LM248DT (STMicroelectronics) is a general-purpose amplifier rather than a J-FET amplifier and does not meet the primary substitution criteria. The TL074CDG4 (Texas Instruments) is obsolete and exhibits different electrical characteristics including higher input bias current (65 pA) and different supply voltage specifications.

Frequently Asked Questions (FAQ)

Q: Can the LF347DR be used as a direct replacement for the LF347MX?

A: Yes. The LF347DR meets all primary substitution criteria with identical slew rate (13V/µs), gain bandwidth product (4 MHz), input bias current (50 pA), and supply voltage range (7V to 36V). Both are J-FET 4-circuit amplifiers in 14-SOIC packages. The LF347DR is currently in active production status with ROHS3 compliance.

Q: What is the difference between the LF347DT and LF347DR?

A: Both parts are J-FET 4-circuit amplifiers with identical package specifications. The primary differences are packaging format (LF347DT is Cut Tape & Digi-Reel®, LF347DR is also Cut Tape & Digi-Reel®) and electrical performance. The LF347DT offers superior slew rate (16V/µs versus 13V/µs), lower input bias current (20 pA versus 50 pA), and lower input offset voltage (3 mV versus 5 mV). However, the LF347DT supply voltage span is specified as 44V minimum and maximum, which differs from the LF347MX specification of 7V to 36V.

Q: Is the LF347MX/NOPB identical to the original LF347MX?

A: The LF347MX/NOPB is manufactured by Texas Instruments and maintains the same electrical specifications as the onsemi LF347MX, including slew rate (13V/µs), gain bandwidth product (4 MHz), and input bias current (50 pA). The primary difference is the supply voltage minimum specification (10V versus 7V). Both are J-FET 4-circuit amplifiers in 14-SOIC packages with identical operating temperature range (0°C to 70°C).

Q: Why is the LF247DT not recommended as a substitute?

A: While the LF247DT is a J-FET 4-circuit amplifier in a compatible 14-SOIC package, the supply voltage span specification (44V minimum and maximum) differs significantly from the LF347MX requirement (7V to 36V). This specification difference indicates different circuit design parameters and may not provide functional equivalence in applications designed for the original part's voltage range.

Q: What packaging options are available for LF347 substitutes?

A: Substitute parts are available in multiple packaging formats: Tube (LF347D), Tape & Reel (LF247DT), and Cut Tape & Digi-Reel® (LF347DR, LF347DT, LF347MX/NOPB). All substitute parts maintain the same 14-SOIC (0.154", 3.90mm Width) physical package specification, ensuring mechanical compatibility with the original LF347MX footprint.

Q: Are all substitute parts ROHS3 compliant?

A: All active substitute parts listed (LF347DR, LF347BDR, LF347D, LF347DT, LF347MX/NOPB) are ROHS3 compliant. The original LF347MX RoHS status is not specified in the provided data. All parts maintain REACH Unaffected status and MSL 1 (Unlimited) moisture sensitivity rating.

Q: What is the inventory status for substitute parts?

A: The LF347DR has the highest inventory availability with 105,200 units in stock. The LF347DT has 27,321 units, LF347MX/NOPB has 25,200 units, LF347D has 16,726 units, and LF347BDR has 4,007 units in stock. Inventory levels should be verified with the supplier for current availability.

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