FX919BD2 Equivalent & Substitute Parts

Part Overview

The FX919BD2 is a half-duplex 4FSK packet data modulator and discriminator IC manufactured by CML Microcircuits. It functions as an RF modulator/discriminator for general-purpose applications with a 3.3V to 5V supply range, housed in a 24-SOIC package. The device is classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing system support, redesigns, and procurement planning.

Substiute Parts

FX919BD2

CML MicrocircuitsIn Stock: 781FX919BD2 Datasheet

Current PartRFQ

CMX7164Q1

CML MicrocircuitsIn Stock: 1249CMX7164Q1 Datasheet

MFR RecommendedRFQ

FX919BD5

CML MicrocircuitsIn Stock: 3093FX919BD5 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the FX919BD2 is determined by the following critical parameters:

• Function: Modulator and discriminator capability for FSK-based packet data
• Supply Voltage Range: 3.3V to 5V operation
• Mounting Type: Surface mount technology
• RF Type: General-purpose RF signal processing
• Compliance: ROHS3 compliance and equivalent ECCN classification

Two substitute parts are identified:

1. FX919BD5: Direct functional equivalent with identical modulator/discriminator architecture, same supply voltage range, and ROHS3 compliance. Primary difference is package format (24-SSOP vs. 24-SOIC) and improved MSL rating (1 vs. 3).

2. CMX7164Q1: Multi-mode modem supporting FSK and V.23 protocols with 9.6k baud rate capability. Operates within compatible voltage range (3V ~ 3.6V subset of original range), ROHS3 compliant, but uses different package format (64-VQFN) and supports additional data formats beyond 4FSK.

Parameter Comparison

Engineering Selection Recommendations

FX919BD5 is the primary substitute for direct replacement applications. It maintains identical functional architecture (modulator/discriminator), supply voltage compatibility (3.3V ~ 5V), and ROHS3 compliance. The device is in active production status, ensuring long-term availability. The package change from 24-SOIC to 24-SSOP requires PCB layout modification but provides a smaller footprint and superior moisture sensitivity rating (MSL 1 vs. MSL 3), reducing handling and storage constraints.

CMX7164Q1 serves as a functional alternative for applications requiring multi-mode modem capability with FSK support. The 64-VQFN package and expanded feature set (V.23 protocol support, 9.6k baud rate) necessitate significant circuit redesign. The supply voltage range (3V ~ 3.6V) is narrower than the original specification and requires verification against system power distribution. This substitute is appropriate only when the additional modem functionality provides system-level benefits justifying the redesign effort.

Frequently Asked Questions (FAQ)

Q: Can FX919BD5 be used as a direct pin-for-pin replacement for FX919BD2?

A: No. While both devices are 24-pin surface-mount packages with identical functional architecture, FX919BD5 uses SSOP packaging (0.209" width) versus SOIC packaging (0.295" width) for FX919BD2. Pin pitch and footprint differ, requiring PCB layout modification. Pin assignment compatibility must be verified against device datasheets before implementation.

Q: What are the key differences between FX919BD2 and CMX7164Q1?

A: FX919BD2 is a dedicated modulator/discriminator for 4FSK packet data. CMX7164Q1 is a multi-mode modem supporting FSK and V.23 protocols with integrated baud rate capability (9.6k). CMX7164Q1 uses a 64-pin VQFN package versus 24-pin SOIC, operates at a narrower voltage range (3V ~ 3.6V), and requires complete circuit redesign. Selection depends on whether multi-mode modem functionality is required.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. FX919BD2, FX919BD5, and CMX7164Q1 are all ROHS3 compliant, meeting environmental and regulatory requirements for equivalent substitution in compliant applications.

Q: What is the impact of MSL rating differences?

A: FX919BD2 has MSL 3 (168-hour floor life), while FX919BD5 has MSL 1 (unlimited floor life). Lower MSL ratings reduce moisture-related failures during storage and handling. FX919BD5's superior MSL rating simplifies inventory management and reduces risk of moisture-induced defects in manufacturing environments with extended component exposure.

Q: Can CMX7164Q1 operate at 5V supply voltage?

A: No. CMX7164Q1 is specified for 3V ~ 3.6V supply voltage, which does not include the 5V upper limit of FX919BD2. Systems requiring 5V operation cannot use CMX7164Q1 without additional voltage regulation circuitry, introducing design complexity and potential reliability concerns.