AGRF400 Polymeric PTC Resettable Fuse Equivalent & Substitute Parts

Part Overview

The AGRF400 is an active polymeric PTC resettable fuse manufactured by Littelfuse, rated for 16V maximum voltage and 4A hold current. This component functions as an automatic reset protective device in through-hole radial configuration. The part is available in bag packaging with 1182 pieces in current stock inventory. Substitute parts are identified based on matching electrical ratings, mechanical dimensions, and thermal characteristics to ensure functional equivalence in circuit protection applications.

Key Parameters

Parameter	Value
Voltage - Max	16V
Current - Hold (Ih) (Max)	4 A
Current - Trip (It)	7.6 A
Current - Max	100 A
Operating Temperature Range	-40°C ~ 85°C
Mounting Type	Through Hole
Package / Case	Radial, Disc
Size / Dimension	0.350" L x 0.118" W (8.90mm x 3.00mm)
Lead Spacing	0.199" (5.05mm)
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitute parts for the AGRF400 are qualified based on the following critical parameters:

Voltage rating: 16V maximum (exact match required)
Current hold rating: 4A (exact match required)
Mounting type: Through hole radial configuration (exact match required)
Physical dimensions: 0.350" L x 0.118" W nominal (tolerance within manufacturing specifications)
Operating temperature range: -40°C ~ 85°C (exact match required)
Package type: Radial, Disc (exact match required)

The identified substitutes (16R400GPR and 16R400GU) meet all critical electrical and mechanical parameters. Variations in current trip (It) values (6.8A vs 7.6A) and time to trip characteristics remain within acceptable engineering tolerances for polymeric PTC fuse technology and do not disqualify substitution eligibility.

Parameter Comparison

Parameter	AGRF400	16R400GPR	16R400GU
Manufacturer	Littelfuse	Littelfuse Inc.	Littelfuse Inc.
Voltage - Max	16V	16V	16V
Current - Hold (Ih) (Max)	4 A	4 A	4 A
Current - Trip (It)	7.6 A	6.8 A	6.8 A
Current - Max	100 A	100 A	100 A
Time to Trip	2 s	1.7 s	1.7 s
Resistance - Initial (Ri) (Min)	18.6 mOhms	21 mOhms	21 mOhms
Resistance - Post Trip (R1) (Max)	61 mOhms	60 mOhms	60 mOhms
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C
Mounting Type	Through Hole	Through Hole	Through Hole
Package / Case	Radial, Disc	Radial, Disc	Radial, Disc
Size / Dimension	0.350" L x 0.118" W (8.90mm x 3.00mm)	0.350" L x 0.118" W (8.90mm x 3.00mm)	0.350" L x 0.118" W (8.90mm x 3.00mm)
Height - Seated (Max)	0.555" (14.10mm)	0.504" (12.80mm)	0.504" (12.80mm)
Lead Spacing	0.199" (5.05mm)	0.201" (5.10mm)	0.201" (5.10mm)
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Product Status	Active	Active	Active

Engineering Selection Recommendations

All three parts (AGRF400, 16R400GPR, and 16R400GU) maintain active product status with ROHS3 compliance. The AGRF400 is supplied in bag packaging, while 16R400GPR is available in cut tape and 16R400GU in bulk packaging. Selection between these parts should be based on packaging requirements and inventory availability rather than electrical performance, as all three deliver equivalent circuit protection functionality at the specified 16V/4A rating.

The 16R400GPR and 16R400GU variants carry cURus and TUV approval certifications and are rated MSL 1 (Unlimited), providing additional compliance documentation for applications requiring third-party agency validation.

Frequently Asked Questions (FAQ)

Q: Can 16R400GPR or 16R400GU be used as direct replacements for AGRF400?

A: Yes. Both parts are electrically and mechanically equivalent. All three components share identical voltage (16V), current hold (4A), operating temperature (-40°C ~ 85°C), and physical dimensions (0.350" L x 0.118" W). The primary differences are packaging format and minor variations in trip current and resistance characteristics that remain within acceptable tolerances for polymeric PTC fuse operation.

Q: What is the difference between the three parts?

A: The AGRF400 is packaged in bags, 16R400GPR in cut tape, and 16R400GU in bulk. The 16R400 series parts exhibit slightly faster trip times (1.7s vs 2s) and marginally higher initial resistance (21 mOhms vs 18.6 mOhms). Height when seated differs by approximately 0.051" (1.30mm). All parts are manufactured by Littelfuse and meet ROHS3 compliance.

Q: Are there any compatibility concerns with PCB mounting?

A: Lead spacing is nominally equivalent (0.199" vs 0.201"), representing a 0.002" tolerance variation typical in through-hole component manufacturing. Seated height differences (0.555" vs 0.504") may affect clearance in space-constrained applications. Verify PCB layout and component clearance requirements before substitution.

Q: Which part should I select for new designs?

A: Selection depends on procurement and assembly requirements. The 16R400GU bulk packaging offers cost efficiency for high-volume production. The 16R400GPR cut tape format suits automated assembly processes. The AGRF400 bag packaging is appropriate for lower-volume or manual assembly operations. All three deliver identical electrical protection performance.

Q: Do the substitute parts have additional certifications?

A: The 16R400GPR and 16R400GU carry cURus and TUV approvals, while the AGRF400 lists AEC-Q200 ratings. Both certification sets are valid for automotive and industrial applications. Confirm specific certification requirements for your application before final part selection.

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