SN54HC157-SP - QML-V Quad 2:1 Multiplexer | Texas Instruments
MPN: SN54HC157-SP ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $45 | $45.00 |
| 10 | $42 | $420.00 |
| 25 | $39 | $975.00 |
| 50 | $36 | $1,800.00 |
| 100 | $33 | $3,300.00 |
SN54HC157-SP Overview
A data selector/multiplexer is a combinational logic circuit that forwards one of several input signals to a common output. Multiplexers are fundamental building blocks of digital data-path design, used for bus arbitration, register file selection, and redundant path switching. The SN54HC157-SP implements the 2-to-1 multiplexing function for four independent channels and belongs to the HC (high-speed CMOS) logic family, which combines CMOS low static power with TTL-compatible drive capability.
Key features include a wide operating supply range of 2 V to 6 V, low power consumption with a maximum ICC of 80 uA, and outputs that can drive up to 15 LSTTL loads. Typical propagation delay is 11 ns, with balanced +/-6-mA output drive at 5 V operation. The device is qualified to QML-V (MIL-PRF-38535 Appendix V) standards for radiation tolerance, making it appropriate for satellite and deep-space missions.
Technically, the device uses a CMOS process providing high noise immunity and low static dissipation. Internal inverters and drivers supply full data selection to the four output gates. When the strobe (G) is high, all outputs are forced low, simplifying bus isolation. Inputs accept standard CMOS levels and are TTL compatible at 5 V operation.
Typical applications include data routing in spacecraft telemetry systems, selection between primary and backup data paths in redundant architectures, and switching between instrument outputs in satellite payloads to conserve downlink bandwidth. The -55C to +125C operating range and hermetic ceramic DIP (CDIP-16) packaging support these extreme environments.
When designing with this device, decouple VCC close to the pins, drive the strobe input to a known state during power-up, and verify select and data inputs meet setup and hold requirements relative to the system clock, considering the 11 ns typical propagation delay.
Drop-in alternatives for SN54HC157-SP — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
SN54HC157
✅ Drop-In📋 Reference alternative (not in catalog)
CD74HC157M96
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
MC54HC157A
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
CD4019B-MIL
⚡ Same Package ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
SN54HC157-SP Maximum Ratings & Electrical Characteristics
| Function | Quadruple 2-line to 1-line data selector/multiplexer |
| Logic Family | HC (High-Speed CMOS) |
| Supply Voltage Range | 2 V to 6 V |
| Max Quiescent Current ICC | 80 uA |
| Typical Propagation Delay | 11 ns |
| Output Drive | +/-6 mA at 5 V |
| LSTTL Load Drive | Up to 15 loads |
| Strobe Input | Active-low (G); high forces all outputs low |
| Select Input | Common A/B address select |
| Input Type | CMOS, TTL compatible at 5 V |
| Operating Temperature | -55C to +125C |
| Package | CDIP-16 (hermetic ceramic DIP) |
| Mounting Type | Through Hole |
| Quality Qualification | QML-V (MIL-PRF-38535 Appendix V), radiation tolerant |
| Channels | 4-bit word selection from one of two sources |
SN54HC157-SP Pin Configuration
| Pin 1 | A/B — Common select input (low = A inputs, high = B inputs) |
| Pin 2 | 1A — Data input A, channel 1 |
| Pin 3 | 1B — Data input B, channel 1 |
| Pin 4 | 1Y — Output, channel 1 |
| Pin 5 | 2A — Data input A, channel 2 |
| Pin 6 | 2B — Data input B, channel 2 |
| Pin 7 | 2Y — Output, channel 2 |
| Pin 8 | GND — Ground |
| Pin 9 | 3Y — Output, channel 3 |
| Pin 10 | 3A — Data input A, channel 3 |
| Pin 11 | 3B — Data input B, channel 3 |
| Pin 12 | 4Y — Output, channel 4 |
| Pin 13 | 4A — Data input A, channel 4 |
| Pin 14 | 4B — Data input B, channel 4 |
| Pin 15 | G — Strobe input (active-low; high forces all outputs low) |
| Pin 16 | VCC — Supply voltage, 2 V to 6 V |
Typical Applications
SN54HC157-SP is suitable for 6 applications: Spacecraft Telemetry Data Routing, Redundant Primary/Backup Path Selection, Satellite Payload Instrument Multiplexing, Bus Isolation in High-Reliability Digital Systems, Register File and Data-Path Source Selection, Industrial Control Signal Source Switching.
Spacecraft Telemetry Data Routing
The SN54HC157-SP routes 4-bit telemetry words between redundant sensor chains and the downlink formatter. Its QML-V qualification and radiation tolerance suit LEO and deep-space missions, while the 80 uA maximum ICC keeps power budgets tight. With an 11 ns typical propagation delay, it comfortably handles low-rate telemetry buses; designers place it between sensor outputs and the encoder, using the strobe input to gate data during format switching.
Recommended
Redundant Primary/Backup Path Selection
In fault-tolerant spacecraft and avionics architectures, the SN54HC157-SP selects between primary and backup 4-bit data buses. The common A/B select input switches all four channels simultaneously, and the active-low strobe (G) forces outputs low during failover to avoid glitching downstream logic. Its hermetic CDIP-16 package and -55C to +125C range support vacuum and wide-temperature environments where plastic-packaged parts cannot be used.
Recommended
Satellite Payload Instrument Multiplexing
Satellite payloads use the SN54HC157-SP to time-share a single downlink channel among multiple instrument outputs, conserving bandwidth. Four instrument bits are selected from one of two instruments per A/B control. The HC family's TTL-compatible inputs at 5 V interface directly with legacy payload electronics, and the 11 ns typical delay adds negligible latency. The strobe input blanks outputs between instrument windows to reduce switching artifacts in the telemetry stream.
Recommended
Bus Isolation in High-Reliability Digital Systems
The active-low strobe (G) makes the SN54HC157-SP effective for bus isolation: a high on G forces all four outputs low, deterministically releasing a shared bus. The device's +/-6 mA balanced drive at 5 V and ability to drive 15 LSTTL loads allow direct connection to heavily loaded military-temperature buses. Combined with 80 uA maximum ICC, multiple devices can share a backplane without significant static power penalty.
Recommended
Register File and Data-Path Source Selection
In military and aerospace digital data-paths, the SN54HC157-SP performs source selection between two register banks or computational results. The HC family combines CMOS low static power with TTL-compatible drive, and the 11 ns typical propagation delay supports multi-MHz sequential logic. Designers must meet select and data setup/hold requirements relative to the system clock and use the strobe to hold outputs stable during pipeline transitions.
Recommended
Industrial Control Signal Source Switching
Where radiation qualification is not required but wide temperature and hermetic packaging are valued, the SN54HC157-SP switches between two 4-bit industrial control or status sources. Its 2-6 V supply range supports both 3.3 V and 5 V control systems, and the -55C to +125C rating covers extreme factory-floor and outdoor installations. Commercial users seeking lower cost can substitute CD74HC157 variants with the same logic function.
Recommended
Recommended Products Summary
Engineering reference data for SN54HC157-SP — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | SN54HC157 | CD74HC157M96 | MC54HC157A |
|---|---|---|---|---|
| Package | CDIP-16 (hermetic) | CDIP-16 - same | CDIP-16 - same | CDIP-16 - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | onsemi |
| Function | Quad 2:1 data selector/mux | Quad 2:1 data selector/mux | Quad 2:1 data selector/mux | Quad 2:1 data selector/mux |
| Supply Voltage | 2 V to 6 V | 2 V to 6 V | 2 V to 6 V | 2 V to 6 V |
| QML-V Qualification | Yes (MIL-PRF-38535 Appendix V) | No | No | No |
| Operating Temperature | -55C to +125C | -55C to +125C | -55C to +125C | -55C to +125C |
Key Differentiators
- QML-V radiation-tolerant qualification (vs SN54HC157)
- Hermetic CDIP-16 packaging (vs CD74HC157)
- Low static power with TTL drive (vs CD4019B-MIL)
Design Notes
Decouple VCC with a 0.1 uF ceramic capacitor placed within a few millimeters of pin 16 and GND pin 8. On spaceflight boards, use a single via to the ground plane per decoupling cap and avoid long stub traces to the select and strobe lines to limit noise coupling into the CMOS inputs.
Do not leave the strobe (G) input floating during power-up; undefined logic levels on CMOS inputs can cause bus contention. Drive G high to force outputs low until system initialization completes. Also ensure unused A or B input pairs are tied to a defined level, as HC-family inputs must never float.
With an 11 ns typical propagation delay, verify select (A/B) setup and hold timing against the system clock when switching data sources mid-frame. Glitch-free source changeover requires switching only when strobe (G) is high, which forces outputs low and masks select-transition transients.
Static dissipation is negligible at 80 uA maximum ICC; thermal design is dominated by output drive loading. At +/-6 mA per output and a 0.5 V output drop, worst-case dissipation is roughly 12 mW per driven-low output plus dynamic switching losses, well within CDIP-16 capability without heatsinking.
Compliance Information
Space-qualified device per MIL-PRF-38535 Appendix V (QML-V). RoHS/REACH status not stated in provided data; hermetic military packaging may use leaded glass seal - confirm with TI before RoHS-restricted builds.
