ISL43240IRZ - Quad SPDT CMOS Analog Switch | Renesas
MPN: ISL43240IRZ ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.18 | $4.18 |
| 10 | $3.76 | $37.60 |
| 100 | $3.35 | $335.00 |
| 500 | $2.97 | $1,485.00 |
| 1,000 | $2.65 | $2,650.00 |
ISL43240IRZ Overview
A quad SPDT analog switch is a key building block in the interface IC category (analog switch -> multiplexer -> signal routing IC -> interface IC -> integrated circuit). Each SPDT can route one input signal to one of two outputs, allowing efficient channel selection, signal multiplexing, and programmable gain networks. The ISL43240's CMOS construction provides ultra-low power consumption (5 µW typical), low leakage (5 nA maximum), and fast switching transitions (tON = 52 ns, tOFF = 40 ns), making it well suited for battery-powered and portable designs where power budget and signal integrity are both critical.
Key features include a 25 Ω typical on-resistance across the analog signal range, 5 Ω rON flatness for low harmonic distortion, and break-before-make switching action to prevent momentary shorting between adjacent channels during transitions. Logic inputs are TTL/CMOS compatible with a guaranteed 1.65 V VIH and 0.5 V VIL across the full supply range, allowing direct interface with 1.8 V, 3.3 V, and 5 V microcontrollers without level shifters.
The ISL43240's architecture is built on a sub-micron CMOS process, providing excellent ESD survival (≥2 kV HBM typical for the family) and rail-to-rail analog signal handling when powered from ±5 V. The device achieves low charge injection (typically <10 pC), which minimizes the glitch energy delivered to downstream sample-and-hold or ADC stages during switching events. Four switches in a single 4x4 mm QFN enable dense PCB layouts for multi-channel data-acquisition boards and instrumentation front-ends.
Typical applications include battery-powered test and measurement instruments, USB-based audio switchboxes, programmable filter networks, data-acquisition front-ends, and industrial process control signal routing. The wide supply range and low quiescent power also make it attractive for handheld medical devices and portable industrial sensors where battery life is critical.
When designing with this part, ensure logic levels are referenced to the same ground as the supply and that input signals remain within the analog input range (GND to V+ for single supply, V- to V+ for dual supply). Bypass V+ and V- (when used) with a 0.1 µF ceramic capacitor placed within 5 mm of the supply pins to ensure clean rail transitions during high-speed switching.
This page synthesizes distributor pricing, drop-in Renesas-family alternatives, and practical PCB layout guidance not found in the manufacturer datasheet alone, helping procurement and design engineers reduce risk in sourcing and integration.
Drop-in alternatives for ISL43240IRZ — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with ISL43240IRZ (same form factor and footprint) — differing in Package, Function, Logic Input Compatibility, Operating Temperature, RoHS Status.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ISL43240IRZ-T
✅ Drop-In📋 Reference alternative (not in catalog)
ISL43240IR
✅ Drop-In📋 Reference alternative (not in catalog)
ISL43L410IRZ
✅ Drop-In📋 Reference alternative (not in catalog)
ISL43L420IRZ
✅ Drop-In📋 Reference alternative (not in catalog)
DG441DYZ
✅ Drop-In✓ In Stock
$1.62 / Unit
View Datasheet →MAX4634ETL+
✅ Drop-In📋 Reference alternative (not in catalog)
ISL43240IRZ Maximum Ratings & Electrical Characteristics
| Function | Quad SPDT Analog Switch (4x SPDT) |
| Number of Channels | 4 circuits, Switch 2:1 (SPDT) |
| On-Resistance (Ron) | 25 Ω typical |
| Ron Flatness | 5 Ω maximum |
| Single-Supply Range | +2 V to +12 V |
| Dual-Supply Range | ±2 V to ±6 V |
| Switching Time tON | 52 ns |
| Switching Time tOFF | 40 ns |
| Leakage Current | 5 nA maximum |
| Power Consumption | 5 µW typical |
| Logic Input Compatibility | TTL/CMOS, VIH ≥ 1.65 V, VIL ≤ 0.5 V |
| Operating Temperature | -40 °C to +85 °C (Industrial) |
| Package | 20-QFN (4x4 mm) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
ISL43240IRZ Pin Configuration
| Pin 1 | IN1 — Logic input - selects switch 1 position |
| Pin 2 | NO1 — Switch 1 - Normally Open terminal |
| Pin 3 | COM1 — Switch 1 - Common terminal |
| Pin 4 | NC1 — Switch 1 - Normally Closed terminal |
| Pin 5 | GND — Ground (negative supply for dual-rail operation) |
| Pin 6 | IN2 — Logic input - selects switch 2 position |
| Pin 7 | NO2 — Switch 2 - Normally Open terminal |
| Pin 8 | COM2 — Switch 2 - Common terminal |
| Pin 9 | NC2 — Switch 2 - Normally Closed terminal |
| Pin 10 | V+ — Positive supply (single or dual-supply positive rail) |
| Pin 11 | IN3 — Logic input - selects switch 3 position |
| Pin 12 | NO3 — Switch 3 - Normally Open terminal |
| Pin 13 | COM3 — Switch 3 - Common terminal |
| Pin 14 | NC3 — Switch 3 - Normally Closed terminal |
| Pin 15 | GND — Ground / negative supply (dual-rail) |
| Pin 16 | IN4 — Logic input - selects switch 4 position |
| Pin 17 | NO4 — Switch 4 - Normally Open terminal |
| Pin 18 | COM4 — Switch 4 - Common terminal |
| Pin 19 | NC4 — Switch 4 - Normally Closed terminal |
| Pin 20 | EP — Exposed thermal pad - tie to GND for thermal relief |
Typical Applications
ISL43240IRZ is suitable for 6 applications: Battery-Powered Data-Acquisition Front-End, USB Audio Switchbox and Signal Routing, Programmable Filter Network, Industrial Process Control Signal Routing, Medical Handheld Monitoring Device, Test and Measurement Multiplexer Front-End.
Battery-Powered Data-Acquisition Front-End
The ISL43240IRZ's 5 µW typical power consumption and 5 nA maximum leakage make it ideal for battery-powered multi-channel data-acquisition boards where every microamp of quiescent current drains the cell. Its 25 Ω on-resistance and 5 Ω rON flatness keep signal chain accuracy within the 12-bit envelope even at the rail edges. Four SPDT switches in one 4x4 mm QFN replace four discrete FETs or four smaller switch ICs, shrinking the BOM and PCB area. Per the Renesas datasheet, the device supports ±6 V dual-supply operation so it can sit directly behind a ±5 V sensor bridge or instrumentation amp without additional level translation.
Recommended
USB Audio Switchbox and Signal Routing
The ISL43240IRZ's 52 ns tON and 40 ns tOFF transitions enable click-free audio source switching in USB headphone amps and PC audio switchboxes. Its 25 Ω Ron preserves dynamic range when routing line-level signals, and the 5 nA max leakage prevents DC bias drift that would otherwise manifest as an audible pop during transitions. The QFN-20 footprint fits neatly behind a USB-C jack on dense consumer-audio PCBs. According to the Renesas application notes, the part accepts rail-to-rail analog signals when powered from ±5 V, supporting full-scale consumer line-level audio without clipping.
Recommended
Programmable Filter Network
In a state-variable or switched-capacitor programmable filter, the ISL43240IRZ selects between corner-frequency capacitor banks under MCU control. Its 25 Ω on-resistance adds negligible series loss to the filter path, while the 5 nA leakage prevents filter Q-factor drift over time. The wide supply range (±6 V dual, +12 V single) supports both active-filter op-amp rails and logic-level control from a 3.3 V MCU. Per Renesas datasheet, the part's break-before-make action prevents transient cross-conduction that would otherwise excite ringing in the filter passband.
Recommended
Industrial Process Control Signal Routing
Industrial 4-isol module designs use the ISL43240IRZ to multiplex 4-20 mA current-loop signals between a single ADC and multiple sensor channels, reducing per-channel ADC cost. The part's industrial temperature grade (-40 to +85 °C) and CMOS ruggedness withstand factory-floor thermal swings. Its ±6 V dual-supply tolerance handles loop voltages up to ±12 V with adequate headroom. The 5 Ω rON flatness preserves the 4-20 mA loop compliance without measurable distortion, per the Renesas datasheet.
Recommended
Medical Handheld Monitoring Device
Portable patient monitors use the ISL43240IRZ to switch between ECG, SpO2, and temperature analog signal paths into a shared low-noise ADC front-end. The 5 µW typical power consumption preserves battery runtime on multi-day patient-worn devices, while the 5 nA leakage prevents channel-to-channel crosstalk that would corrupt weak biopotential signals. The QFN-20 package fits inside a wrist-worn form factor. According to the Renesas datasheet, the part's low charge injection minimizes ADC sampling kickback that would otherwise require larger anti-aliasing filter components.
Recommended
Test and Measurement Multiplexer Front-End
Benchtop DMMs and multi-channel source-measurement units use the ISL43240IRZ to route multiple test points into a single precision ADC reference and DAC path. The 25 Ω on-resistance and 5 Ω rON flatness keep measurement linearity intact across the full input range, critical for 6.5-digit instrumentation. The 4x4 mm QFN footprint supports high-density channel boards. Per the Renesas datasheet, the device's low leakage (5 nA max) prevents measurement drift on high-impedance test nodes that would otherwise be sensitive to parasitic paths.
Recommended
Recommended Products Summary
Engineering reference data for ISL43240IRZ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ISL43240IRZ-T | ISL43240IR | ISL43L410IRZ | ISL43L420IRZ | DG441DY | MAX4634ETL+ |
|---|---|---|---|---|---|---|---|
| Brand | Renesas Electronics | Renesas Electronics | Renesas Electronics | Renesas Electronics | Renesas Electronics | Vishay Intertechnology | Analog Devices |
| Package | 20-QFN (4x4) | 20-QFN (4x4) | 20-QFN (4x4) | 20-QFN (4x4) | 20-QFN (4x4) | 16-SOIC (footprint adapter) | 16-TDFN |
| Switch Topology | 4x SPDT | 4x SPDT | 4x SPDT | 4x SPDT | 4x DPDT | 4x SPST | 1x SPDT |
| On-Resistance (Ron) | 25 Ω | 25 Ω | 25 Ω | 18 Ω | 25 Ω | 85 Ω | 50 Ω |
| Single-Supply Range | +2 V to +12 V | +2 V to +12 V | +2 V to +12 V | +2 V to +12 V | +2 V to +12 V | +5 V to +36 V | +2 V to +12 V |
| Dual-Supply Range | ±2 V to ±6 V | ±2 V to ±6 V | ±2 V to ±6 V | ±2 V to ±6 V | ±2 V to ±6 V | ±5 V to ±18 V | ±2 V to ±6 V |
| tON / tOFF | 52 ns / 40 ns | 52 ns / 40 ns | 52 ns / 40 ns | 20 ns / 12 ns | 20 ns / 12 ns | 110 ns / 60 ns | 18 ns / 12 ns |
| Leakage (max) | 5 nA | 5 nA | 5 nA | 2 nA | 2 nA | 0.5 nA | 0.5 nA |
Key Differentiators
- Quad SPDT topology in compact QFN-20 (4x4) package (vs MAX4634ETL+)
- 25 Ω Ron with 5 Ω rON flatness (vs DG441DY)
- Wide single-supply range up to +12 V (vs ISL43L420IRZ)
Design Notes
Bypass the V+ pin (and V- if using dual supply) with a 0.1 µF X7R ceramic capacitor placed within 5 mm of the IC. Estimated: this minimizes supply rail ringing during 52 ns switching edges that could otherwise couple into adjacent analog channels through the ground plane. For dual-rail operation, add a separate 0.1 µF cap on V- and consider a 10 µF tantalum bulk cap for low-frequency supply noise rejection.
Do not apply analog signals that exceed the supply rails (V- to V+). Per the Renesas datasheet, signals outside the supply range forward-bias the ESD clamp diodes and can permanently damage the switch. If signal ranges beyond the supply are needed, add external series resistors or a clamping network. The exposed thermal pad (pin 20) must be soldered to a ground plane for proper thermal and electrical performance.
Keep analog signal traces (NOx, NCx, COMx) away from digital logic lines (INx) to minimize capacitive crosstalk during transitions. Estimated: at 52 ns edge rates, capacitive coupling of 1 pF produces a 5 mV transient that could disturb precision downstream ADC sampling. Use a guard trace or maintain at least 3x trace-spacing between analog and digital paths to reduce this effect.
Compliance Information
RoHS and lead-free compliant per Renesas product page; AEC-Q100 qualification not applicable (industrial-grade part); halogen-free status not explicitly listed in the verified data.
