TC-38.400MBD-T MEMS Oscillator Equivalent & Substitute Parts

Part Overview

The TC-38.400MBD-T is a 38.4 MHz MEMS-based XO (Standard) oscillator manufactured by TXC CORPORATION. This component operates at 3.3V with CMOS output, Enable/Disable function, and is housed in a 4-SMD, No Lead surface mount package. The part is classified as Obsolete, making identification of equivalent and substitute components essential for ongoing design support and procurement continuity.

Substiute Parts

TC-38.400MBD-T

TXC CORPORATIONIn Stock: 775TC-38.400MBD-T Datasheet

Current PartRFQ

7X-38.400MBD-T

TXC CORPORATIONIn Stock: 8857X-38.400MBD-T Datasheet

DirectRFQ

FK3840012

Diodes IncorporatedIn Stock: 730FK3840012 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the TC-38.400MBD-T is determined by strict alignment of the following critical parameters:

Mandatory Matching Parameters:

• Frequency: 38.4 MHz (exact match required)
• Output Type: CMOS
• Supply Voltage: 3.3V
• Function: Enable/Disable
• Package / Case: 4-SMD, No Lead
• Size / Dimension: 0.126" L x 0.098" W (3.20mm x 2.50mm)
• Mounting Type: Surface Mount
• Moisture Sensitivity Level: 1 (Unlimited)

Allowable Variation Parameters:

• Frequency Stability: ±25ppm or better (lower values acceptable)
• Operating Temperature Range: Must encompass or match -40°C ~ 85°C
• Current - Supply (Max): Variation acceptable if within circuit design limits
• Base Resonator: MEMS or Crystal (both acceptable for this application)
• Height - Seated (Max): Minor variation acceptable within PCB assembly constraints

Two substitute parts meet these criteria and are listed below.

Parameter Comparison

Engineering Selection Recommendations

7X-38.400MBD-T (Direct Substitute - Recommended Primary Choice)

The 7X-38.400MBD-T is manufactured by TXC CORPORATION, the same original equipment manufacturer as the TC-38.400MBD-T. This part maintains identical electrical specifications (frequency, voltage, function, output type, frequency stability, and operating temperature range) and identical package dimensions. The primary differences are:

• Product Status: Active (versus Obsolete for TC-38.400MBD-T)
• Base Resonator: Crystal (versus MEMS)
• Current - Supply (Max): 15mA (versus 25mA)
• Height - Seated (Max): 0.043" (1.10mm) (versus 0.031" (0.80mm))
• RoHS Compliance: Confirmed

The reduced current consumption and improved RoHS compliance make this the preferred direct substitute. The increased height requires verification against PCB assembly constraints but remains within typical surface mount tolerances.

FK3840012 (Similar Substitute - Alternative Choice)

The FK3840012 is manufactured by Diodes Incorporated under the SaRonix-eCera™ FK series. This part meets all mandatory matching parameters and offers:

• Product Status: Active
• Frequency Stability: ±20ppm (superior to ±25ppm specification)
• Current - Supply (Max): 10mA (lowest consumption of all options)
• Current - Supply (Disable) (Max): 10µA (specified, unlike other parts)
• RoHS Status: ROHS3 Compliant
• REACH Status: REACH Unaffected

Limitations for this substitute:

• Operating Temperature Range: -20°C ~ 70°C (does not fully encompass -40°C ~ 85°C)
• Height - Seated (Max): 0.045" (1.15mm) (highest of all options)

The FK3840012 is suitable only for applications where the operating temperature range -20°C ~ 70°C is acceptable and PCB assembly height constraints permit 1.15mm seated height.

Frequently Asked Questions (FAQ)

Q: Can the 7X-38.400MBD-T directly replace the TC-38.400MBD-T without circuit modification?

A: Yes. The 7X-38.400MBD-T maintains identical electrical specifications (frequency, voltage, output type, function, frequency stability, and operating temperature range) and identical package footprint. The primary design consideration is the increased seated height (1.10mm versus 0.80mm), which must be verified against PCB assembly clearances. No circuit modifications are required.

Q: What is the significance of the Base Resonator difference (MEMS versus Crystal)?

A: Both MEMS and Crystal resonators are acceptable for this application. The TC-38.400MBD-T uses MEMS technology, while the 7X-38.400MBD-T uses Crystal technology. Both deliver the specified frequency stability (±25ppm) and operating characteristics. The substitution is valid from an electrical and functional standpoint.

Q: Why does the FK3840012 have a restricted operating temperature range?

A: The FK3840012 is specified for -20°C ~ 70°C operation, which does not encompass the full -40°C ~ 85°C range of the original TC-38.400MBD-T. This part is suitable only for applications where the actual operating environment remains within -20°C ~ 70°C. Verify application requirements before selection.

Q: Is the increased current consumption of the TC-38.400MBD-T (25mA) a concern when substituting with lower-current alternatives?

A: No. The 7X-38.400MBD-T (15mA) and FK3840012 (10mA) both consume less current than the original part. Lower current consumption is beneficial for power budget and thermal management. Verify that the power supply and circuit design can accommodate the reduced current draw without affecting oscillator performance.

Q: Are all three parts RoHS compliant?

A: The TC-38.400MBD-T does not specify RoHS status. The 7X-38.400MBD-T is RoHS Compliant. The FK3840012 is ROHS3 Compliant. Both substitutes meet current RoHS requirements. Verify RoHS compliance requirements for your specific application and regulatory jurisdiction.

Q: What is the impact of the seated height difference on PCB assembly?

A: The TC-38.400MBD-T has a maximum seated height of 0.031" (0.80mm). The 7X-38.400MBD-T is 0.043" (1.10mm), and the FK3840012 is 0.045" (1.15mm). These differences are within typical surface mount component tolerances. Verify that PCB assembly equipment and design clearances accommodate the increased height. Consult your PCB assembly partner if height constraints are critical.

Q: Can the FK3840012 be used in applications requiring the full -40°C ~ 85°C temperature range?

A: No. The FK3840012 is specified only for -20°C ~ 70°C operation. Use this part only in applications where the actual operating environment remains within this narrower range. For applications requiring full -40°C ~ 85°C coverage, use the 7X-38.400MBD-T.