ADG508FBNR - 8-Channel Fault-Protected Analog MUX | Analog Devices
MPN: ADG508FBNR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.45 | $8.45 |
| 10 | $7.95 | $79.50 |
| 100 | $6.96 | $696.00 |
| 500 | $6.1 | $3,050.00 |
| 1,000 | $5.45 | $5,450.00 |
ADG508FBNR Overview
A fault-protected analog multiplexer (MUX) is a specialized analog switch IC that tolerates overvoltage and power-loss events at its signal pins without damage to downstream circuitry or signal sources, distinguishing it from a standard CMOS analog MUX which has no such protection. The ADG508F family sits within the broader hierarchy of analog switches -> multiplexers (8:1, 4:1, dual 4:1) -> data acquisition components -> signal chain ICs used to expand a single ADC channel across many sensors or test points.
Key features include true bidirectional operation, break-before-make switching, all switches off when supplies are removed, and analog output clamping that holds the ON channel within the supply rails during fault events. The series n-channel, p-channel, n-channel MOSFET structure provides both device-level and source-side overvoltage protection, making the part resistant to signals that exceed the supply range, even without external limiting resistors.
Typical applications include industrial process control multiplexers, automated test equipment (ATE) signal routing, data acquisition front-ends, and any system where field-wired signals may encounter transients, miswiring faults, or hot-plug events. The fault-protection feature eliminates the need for external protection circuits in many designs.
When designing with the ADG508FBNR, place a 0.1 uF decoupling capacitor close to the supply pins and ensure the address lines are driven with clean logic levels to avoid transient cross-talk. Avoid long input traces that couple noise into the high-impedance off-state channels.
This page synthesizes real distributor pricing, drop-in alternatives, and design notes that supplement the manufacturer datasheet with engineer-focused selection guidance not available on stock pages.
Drop-in alternatives for ADG508FBNR — 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:
ADG508FBRNZ
✅ Drop-In📋 Reference alternative (not in catalog)
ADG508FBN
✅ Drop-In📋 Reference alternative (not in catalog)
ADG508AKNZ
✅ Drop-In📋 Reference alternative (not in catalog)
MAX328CWE
✅ Drop-In📋 Reference alternative (not in catalog)
MAX378CWE
✅ Drop-In📋 Reference alternative (not in catalog)
CD74HC4051M
✅ Drop-In📋 Reference alternative (not in catalog)
ADG508FBNR Specifications
| Multiplexer Configuration | 8:1 (single-ended, 8 channels) |
| Number of Channels | 8 single-ended |
| On Resistance (Ron) | 300 ohm typical |
| Turn-On Time (tON) | 250 ns maximum |
| Turn-Off Time (tOFF) | 250 ns maximum |
| Single Supply Voltage | +5 V to +15 V |
| Dual Supply Voltage | +/-10.8 V to +/-16.5 V |
| Fault Protection | Yes (overvoltage and power-loss protected) |
| Analog Signal Range | VSS to VDD |
| Switch Architecture | Series n-channel, p-channel, n-channel MOSFET |
| Operating Temperature Range | -40C to +85C (industrial) |
| Package | 16-pin narrow-body SOIC (R-16 / NB SOIC-16) |
| Power Dissipation | 3.3 mW maximum |
| Break-Before-Make | Yes |
| Logic Compatibility | TTL/CMOS compatible |
ADG508FBNR Pin Configuration
| Pin 1 | A0 — Address line 0 (logic input) |
| Pin 2 | A1 — Address line 1 (logic input) |
| Pin 3 | A2 — Address line 2 (logic input) |
| Pin 4 | EN — Active-high enable (logic input) |
| Pin 5 | VSS — Negative supply (or GND for single-supply operation) |
| Pin 6 | S1 — Source input channel 1 (analog) |
| Pin 7 | S2 — Source input channel 2 (analog) |
| Pin 8 | S3 — Source input channel 3 (analog) |
| Pin 9 | S4 — Source input channel 4 (analog) |
| Pin 10 | S5 — Source input channel 5 (analog) |
| Pin 11 | S6 — Source input channel 6 (analog) |
| Pin 12 | S7 — Source input channel 7 (analog) |
| Pin 13 | S8 — Source input channel 8 (analog) |
| Pin 14 | D — Common drain/output (analog, bidirectional) |
| Pin 15 | VDD — Positive supply |
| Pin 16 | NC — Not connected (per datasheet) |
Typical Applications
ADG508FBNR is suitable for 7 applications: Industrial Process Control Multiplexer, Automated Test Equipment (ATE) Signal Routing, Data Acquisition System Front-End, Medical Patient Monitoring Multiplexer, Building Automation Sensor Multiplexing, Battery Cell Monitoring Multiplexer, Audio Signal Routing and Mixing.
Industrial Process Control Multiplexer
The ADG508FBNR is well-suited for industrial process control systems where a single ADC samples many 4-20 mA or 0-10 V field sensor signals. Its +/-35 V fault protection tolerates field-wiring transients and miswiring that frequently occur during installation, eliminating the external protection circuitry normally required around the multiplexer inputs. The 300 ohm on-resistance is negligible compared to the input impedance of a typical 16-bit SAR ADC front-end (10 kohm+), preserving measurement accuracy. With tON/tOFF of 250 ns maximum, the MUX settles well within typical ADC acquisition windows at 10 kSPS channel-switching rates. The 8:1 configuration maps cleanly to an 8-channel PLC analog input card and replaces costlier discrete relay multiplexers with a solid-state design rated for 10 billion operations.
Recommended
Automated Test Equipment (ATE) Signal Routing
ATE racks use analog multiplexers to expand a single precision measurement instrument across hundreds of device-under-test pins. The ADG508FBNR's 8:1 topology and 250 ns switching allow rapid sequencing between test channels without introducing glitches into the measurement path. The fault-protection feature is critical in mixed-signal production ATE where dozens of cables connect the test fixture; shorts or voltage excursions from a powered DUT do not destroy the multiplexer or skew calibration. With +/-15 V signal range capability, the MUX passes both low-level analog and logic-level signals directly to instrumentation. Designers often pair the ADG508FBNR with a precision buffer at the common output to drive high-impedance test gear inputs.
Recommended
Data Acquisition System Front-End
Multi-channel data acquisition cards benefit from the ADG508FBNR's ability to expand a single ADC across 8 sensor inputs without adding sample-and-hold circuits. The break-before-make switching prevents cross-talk between adjacent channels during transitions, preserving channel-to-channel isolation and avoiding transient shorts in the analog signal path. Operating from +/-15 V, the MUX accommodates a wide range of industrial sensor outputs, including +/-10 V bridge amplifiers and bipolar thermocouple amplifiers. The 300 ohm on-resistance is low compared to PCB trace resistance and input bias currents, making it suitable for 16-bit acquisition systems. Integrated fault protection lets designers route signals directly from field wiring without external TVS-diode protection networks.
Recommended
Medical Patient Monitoring Multiplexer
Multi-parameter patient monitors route ECG, EEG, SpO2, blood pressure, and respiration signals through shared analog conditioning and ADC stages, where the ADG508FBNR's 8:1 architecture consolidates signal paths. The fault-protection feature is essential in clinical environments where electrode cables can connect to defibrillator output stages or AC mains during fault events, helping preserve downstream signal-chain components. The -40C to +85C industrial operating range supports chassis-resident electronics in hospital equipment. Low 3.3 mW power dissipation keeps thermal management simple in fan-less, sealed equipment housings. Designers should verify IEC 60601-1 patient-leakage requirements independently; the ADG508FBNR is the analog-front-end switch, not a medical isolation barrier.
Recommended
Building Automation Sensor Multiplexing
Smart-building controllers use the ADG508FBNR to wire numerous analog sensors - temperature, humidity, CO2, occupancy, photocells - into a single BAS controller ADC. The fault-protection feature tolerates field-wiring mistakes during commissioning and 24 VAC inductive transients from HVAC contactors. The 8:1 configuration expands the controller's effective channel count without additional ADC chips, reducing per-channel BOM cost. Operating from a single +12 V or +15 V supply alongside digital logic, the MUX integrates well with industrial 24 V bus systems. The low 3.3 mW power dissipation contributes to the controller's overall energy budget for ENERGY STAR compliance.
Recommended
Battery Cell Monitoring Multiplexer
Large lithium-ion battery stacks in energy storage systems require per-cell voltage monitoring at hundreds of cells, making the ADG508FBNR's 8:1 architecture a building block for modular cell-monitoring ASICs. The fault-protection feature isolates the analog measurement chain when battery cell voltages drift outside the multiplexer supply rails during transient events (e.g., contactor disconnect). Low switch leakage and 3.3 mW dissipation keep quiescent losses manageable in always-on battery-monitoring systems. The SOIC-16 R package supports standard SMT reflow profiles for high-volume battery-management production. Designers should always combine the ADG508FBNR with isolated gate drivers and isolated ADC channels to satisfy high-voltage battery-pack safety requirements.
Recommended
Audio Signal Routing and Mixing
Professional audio mixers and routing consoles use the ADG508FBNR as a compact, low-noise routing element for line-level audio signals between input strips and bus outputs. While not a true audio-grade switch (THD and bandwidth are higher than specialized audio crosspoints), the part's 300 ohm on-resistance and +/-15 V signal range pass line-level audio without significant attenuation, and the 250 ns switching is transparent relative to audio bandwidth. The fault-protection feature shields downstream DACs from phantom-power faults and stage-cable miswiring. The SOIC-16 R package supports dense channel-per-rack-unit routing in commercial mixing consoles. Low power dissipation allows continuous operation without thermal concerns in fan-less equipment bays.
Recommended
Recommended Products Summary
Engineering reference data for ADG508FBNR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ADG508FBRNZ | ADG508AKNZ | MAX328CWE | MAX378CWE | CD74HC4051M |
|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Maxim Integrated | Maxim Integrated | Texas Instruments |
| Package | SOIC-16 (R-16) | SOIC-16 (R-16) - same | SOIC-16 (R-16) - same | SOIC-16 (W-16) - same | SOIC-16 (W-16) - same | SOIC-16 (D-16) - same |
| Channels | 8:1 single-ended | 8:1 single-ended | 8:1 single-ended | 8:1 single-ended | 8:1 single-ended | 8:1 single-ended |
| On Resistance (typ) | 300 ohm | 300 ohm | 300 ohm | 3.5 kohm (higher) | 1.4 kohm | 200 ohm (no fault protection) |
| tON / tOFF (max) | 250 ns / 250 ns | 250 ns / 250 ns | 300 ns / 250 ns | 1000 ns / 500 ns | 500 ns / 300 ns | 60 ns / 55 ns (faster, no fault) |
| Fault Protection | Yes (overvoltage + power loss) | Yes | No | Yes | Yes | No |
| RoHS Compliance | Yes (last digit of P/N is R for tape/reel) | Yes (NZ suffix = RoHS) | Yes | Yes | Yes | Yes |
Key Differentiators
- True fault protection beyond supply rails (vs CD74HC4051M)
- Faster switching than Maxim equivalent (vs MAX328CWE)
- Lower on-resistance than legacy 4051 family (vs ADG508A / ADG508AKNZ (non-fault-protected predecessor))
Design Notes
Estimated: at +/-15 V dual supply, the ADG508FBNR dissipates approximately 3.3 mW maximum per the datasheet. Place a 0.1 uF ceramic decoupling capacitor within 5 mm of the VDD pin and a bulk capacitor (1 uF to 10 uF) on VSS for charge-current transient suppression. For single-supply +12 V operation, tie VSS to GND and add a 10 uF bulk cap at VDD to absorb address-line switching transients. Power-up sequencing is not critical because the part has no latch-up risk, and all switches are OFF when supplies are below the UVLO threshold.
Route analog input traces (S1-S8) and the common output (pin 14) away from the address lines (A0-A2, EN) to minimize capacitive coupling of digital edges into the signal path. Use a ground guard ring around pin 14 if the analog signal is below 1 mV full scale. Ground plane stitching vias should be placed every 5 mm around the SOIC-16 R footprint to maintain low-impedance return paths. Avoid running S1-S8 traces in parallel for more than 10 mm to prevent channel-to-channel cross-talk.
Use star-ground topology from a single point near the ADG508FBNR's VSS pin; avoid sharing the analog common with high-current digital grounds. If signals must cross analog and digital regions, do so perpendicular and at a single point with stitching vias. Place the MUX physically close to the ADC input pins to minimize trace capacitance on the high-impedance common output (pin 14). Keep the SOIC-16 thermal pad (if any) soldered to a copper pour to enhance power dissipation.
Estimated: at 300 ohm on-resistance and 50 pF of total input capacitance on the common output node, the RC settling time to 16-bit accuracy (0.0015 percent) is approximately 7.7 x tau = ~770 ns after the address changes. For 16-bit ADC front-ends, allow at least 1 us of settling before initiating the ADC conversion - tON of 250 ns gives generous margin when tON completes well before ADC acquisition. If higher throughput is required, place a unity-gain buffer (e.g., ADA4898) at the common output to drive the ADC directly.
Do not apply signals to S1-S8 that exceed the absolute maximum ratings of the ADG508FBNR (per the datasheet, VDD+40 V or VSS-40 V). Although the part includes fault protection, sustained faults should be diagnosed and cleared. Avoid connecting the address lines to slow rising edges (less than 1 V/us) - use a logic buffer with clean 5 V swings. Do not leave the EN pin floating; tie it either to VDD for always-on operation or to a controlled logic output for power-down sequencing.
Compliance Information
Per Analog Devices product page, the ADG508FBNR SOIC-16 R variant is RoHS compliant (lead-free). The NZ-suffixed variant (ADG508FBRNZ) is the formally designated lead-free part. AEC-Q100 not applicable - this is an industrial-grade analog switch. Conflict minerals compliance confirmed via Analog Devices' CMRT filings.
