REF1004I-2.5 Equivalent & Substitute Parts

Part Overview

The REF1004I-2.5 is a shunt voltage reference IC manufactured by Texas Instruments, delivering a fixed 2.5V output with ±0.4% tolerance. This component is classified as a Power Management (PMIC) device and is currently in Last Time Buy status. The REF1004I-2.5 operates across the industrial temperature range of -40°C to 85°C and is packaged in 8-SOIC surface mount configuration. Due to its Last Time Buy status, identifying functionally equivalent substitute parts is essential for design continuity and long-term supply chain planning.

Substiute Parts

REF1004I-2.5

Texas InstrumentsIn Stock: 3410REF1004I-2.5 Datasheet

Current PartRFQ

REF35250QDBVR

Texas InstrumentsIn Stock: 744REF35250QDBVR Datasheet

MFR RecommendedRFQ

LT1004IS8-2.5#PBF

Analog Devices Inc.In Stock: 1495LT1004IS8-2.5#PBF Datasheet

DirectRFQ

LT1004IS8-2.5#TRPBF

Analog Devices Inc.In Stock: 15854LT1004IS8-2.5#TRPBF Datasheet

DirectRFQ

LT1004CS8-2.5#PBF

Analog Devices Inc.In Stock: 3824LT1004CS8-2.5#PBF Datasheet

MFR RecommendedRFQ

LT1004CS8-2.5#TRPBF

Analog Devices Inc.In Stock: 2145LT1004CS8-2.5#TRPBF Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the REF1004I-2.5 is determined by the following critical parameters: reference type (shunt), fixed output voltage (2.5V), output current capability (20 mA), tolerance specification (±0.4% or better), temperature coefficient performance, noise characteristics, and operating temperature range compatibility. Package compatibility in 8-SOIC form factor is required for direct PCB replacement without layout modification.

The substitute parts identified fall into two categories:

Direct Shunt Reference Substitutes (Analog Devices LT1004 Series): These parts maintain identical shunt reference architecture, 2.5V output, 20 mA output current, and 8-SOIC packaging. Tolerance specifications range from ±0.8%, which is acceptable for applications where the REF1004I-2.5's ±0.4% tolerance is not a hard requirement. Temperature coefficient remains at 20 ppm/°C typical, and noise performance is identical at 120 µVrms.

Alternative Series Reference Substitute (Texas Instruments REF35250QDBVR): This part represents a different reference architecture (series type rather than shunt type) with superior electrical characteristics including ±0.05% tolerance and 12 ppm/°C temperature coefficient. However, it requires different circuit topology, operates at different voltage input ranges (2.75V to 6V), and is packaged in SOT-23-6 form factor, necessitating PCB redesign.

Parameter Comparison

Engineering Selection Recommendations

For Direct Pin-Compatible Replacement (No PCB Redesign):

The LT1004IS8-2.5#TRPBF and LT1004IS8-2.5#PBF from Analog Devices are the primary substitutes for the REF1004I-2.5. Both maintain identical shunt reference architecture, 8-SOIC packaging, and electrical performance characteristics including 20 mA output current and 120 µVrms noise specification. The tolerance specification of ±0.8% is wider than the REF1004I-2.5's ±0.4%, but both parts share the same 20 ppm/°C temperature coefficient and operate across the -40°C to 85°C temperature range. The LT1004IS8-2.5#TRPBF variant in Tape & Reel packaging offers superior moisture sensitivity (MSL 1 vs. MSL 3) and higher inventory availability (15,800 units). Both parts are ROHS3 compliant and maintain full regulatory alignment with the original component.

The LT1004CS8-2.5#PBF and LT1004CS8-2.5#TRPBF variants are functionally equivalent but operate within a narrower temperature range (0°C to 70°C), making them unsuitable for applications requiring the full -40°C to 85°C industrial temperature specification of the REF1004I-2.5.

For Enhanced Performance (PCB Redesign Required):

The REF35250QDBVR represents a superior alternative for applications where tolerance and temperature stability are critical. This series reference IC delivers ±0.05% tolerance and 12 ppm/°C temperature coefficient, substantially outperforming the REF1004I-2.5's ±0.4% tolerance and 20 ppm/°C coefficient. However, the REF35250QDBVR requires different circuit topology (series vs. shunt architecture), operates at different input voltage ranges (2.75V to 6V), and is packaged in SOT-23-6 form factor. Implementation requires PCB redesign and circuit topology modification. This part is ROHS3 compliant and operates across -40°C to 125°C, providing extended temperature coverage.

Frequently Asked Questions (FAQ)

Q: Can the LT1004 series directly replace the REF1004I-2.5 without PCB modification?

A: Yes, the LT1004IS8-2.5#TRPBF and LT1004IS8-2.5#PBF are pin-compatible direct replacements in 8-SOIC packaging. No PCB layout changes are required. Both parts maintain identical pinout, output voltage (2.5V), output current (20 mA), and noise characteristics (120 µVrms). The primary difference is tolerance specification (±0.8% vs. ±0.4%), which is acceptable for most applications not requiring the tighter tolerance of the original part.

Q: What is the difference between the LT1004IS8 and LT1004CS8 variants?

A: The primary difference is operating temperature range. The LT1004IS8 series operates from -40°C to 85°C, matching the REF1004I-2.5 industrial temperature specification. The LT1004CS8 series operates from 0°C to 70°C, which is narrower and unsuitable for applications requiring full industrial temperature coverage. For direct replacement of the REF1004I-2.5, the LT1004IS8 variants are the correct choice.

Q: What does the packaging designation (#PBF, #TRPBF) indicate?

A: #PBF indicates Tube packaging, while #TRPBF indicates Tape & Reel packaging. Both contain identical die and electrical performance. Tape & Reel packaging offers superior moisture sensitivity (MSL 1 vs. MSL 3 for tube) and is preferred for high-volume manufacturing and automated assembly processes. Tube packaging is suitable for lower-volume applications and manual assembly.

Q: Why is the REF35250QDBVR listed as a substitute if it requires PCB redesign?

A: The REF35250QDBVR is identified as a manufacturer-recommended alternative for applications where superior electrical performance justifies redesign effort. Its ±0.05% tolerance and 12 ppm/°C temperature coefficient provide significantly better accuracy and stability than the REF1004I-2.5. However, because it uses series reference architecture instead of shunt architecture and requires different input voltage ranges (2.75V to 6V), circuit topology modification is necessary. This part is suitable only for new designs or redesign projects where performance improvement is a priority.

Q: Are all substitute parts ROHS3 compliant?

A: Yes, all identified substitute parts (LT1004IS8-2.5#PBF, LT1004IS8-2.5#TRPBF, LT1004CS8-2.5#PBF, LT1004CS8-2.5#TRPBF, and REF35250QDBVR) are ROHS3 compliant, maintaining full regulatory alignment with the REF1004I-2.5.

Q: What is the moisture sensitivity level (MSL) and why does it matter?

A: MSL rating indicates the maximum time a component can be exposed to ambient conditions (typically 30°C/85% RH) before soldering. The REF1004I-2.5 has MSL 3 (168 hours), while the LT1004 variants have MSL 1 (unlimited). Lower MSL ratings provide greater flexibility in manufacturing and storage. The LT1004 variants' superior MSL rating reduces risk of moisture-induced failures during assembly and storage.

Q: Can the REF1004I-2.5 be used interchangeably with the LT1004 in existing designs?

A: Yes, for designs currently using the LT1004IS8-2.5 variants. The REF1004I-2.5 is functionally equivalent with superior tolerance (±0.4% vs. ±0.8%), making it a drop-in replacement. However, the reverse substitution (LT1004 for REF1004I-2.5) requires verification that the application can tolerate the wider ±0.8% tolerance specification.