MAX3535EEWI+T is a high-speed, low-power, 4-channel analog switch/multiplexer designed and manufactured by Maxim Integrated (now part of Analog Devices since 2021). It belongs to the precision, high-bandwidth MAX353x family, engineered specifically for signal routing in high-fidelity data acquisition, communication interfaces, and mixed-signal test systems, where ultra-low on-resistance (RON), minimal charge injection, excellent channel-to-channel crosstalk isolation, and rail-to-rail operation are critical — especially when switching fast or sensitive analog signals (e.g., from sensors, DACs, or ADCs).
The “EEWI” suffix denotes the 28-pin TSSOP package (9.7 mm × 4.4 mm) — a compact, surface-mount, thermally enhanced, and widely manufacturable package; the “+T” indicates tape-and-reel packaging (2,500 units per reel), Pb-free, RoHS-compliant, and qualified for –40°C to +85°C ambient temperature.
â ī¸ Critical Clarification:
The MAX3535 is not a general-purpose CMOS analog switch like the 4066. It is a precision, fully guarded, 4-channel single-pole double-throw (SPDT) switch, featuring:
- Four independent, bidirectional SPDT switches, each with low and matched on-resistance: RON = 3.5 Ω (typ.) at ±5 V supplies, with < 0.5 Ω matching between channels — enabling accurate gain/attenuation switching and minimal signal attenuation error;
- Ultra-low charge injection: 0.2 pC (max) — critical for maintaining accuracy in sampling circuits (e.g., sample-and-hold, switched-capacitor filters, auto-zeroing amplifiers);
- Excellent AC performance: −3 dB bandwidth > 200 MHz, crosstalk < –80 dB @ 10 MHz, and off-isolation > –85 dB @ 10 MHz — preserving signal integrity in wideband applications (e.g., video, RF IF, ultrasound);
- True rail-to-rail analog signal handling: Supports ±5 V dual supplies or +2.7 V to +12 V single supply, with analog input range extending from VSS – 0.2 V to VDD + 0.2 V, allowing overvoltage tolerance and seamless interface with op-amps and ADCs;
- Break-before-make (BBM) switching: Prevents momentary shorting during channel transitions — essential for protecting downstream circuitry and avoiding glitches.
It consumes only 1 µA quiescent current, supports TTL/CMOS-compatible digital control, and features internal ESD protection — all in a compact 28-pin TSSOP.
Introduction
The MAX3535EEWI+T delivers laboratory-grade analog switching performance in a production-ready, space-efficient package:
đš Four high-fidelity SPDT switches in one IC: Replaces multiple discrete switches or complex mux designs — reducing BOM count, layout area, and timing skew across channels;
đš Precision matching & low RON: 3.5 Ω RON with < 0.5 Ω matching enables use in programmable-gain instrumentation amps, calibrated attenuators, and multi-range DMM front-ends without calibration overhead;
đš Near-zero charge injection: At just 0.2 pC max, it’s among the lowest in its class — making it ideal for precision sampling, auto-zero loops, and high-resolution delta-sigma modulator front-ends;
đš Robust, simple integration: Requires only four external decoupling capacitors, no external pull-ups or level shifters — compatible with 1.8 V, 3.3 V, and 5 V logic.
Its 28-pin TSSOP (EEWI) package (9.7 mm × 4.4 mm) offers excellent thermal performance (θJA ≈ 95°C/W), supports AOI inspection, and provides ample pin spacing for high-density routing — ideal for industrial DAQ, medical imaging, and telecom infrastructure.
Key Features
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High-Performance 4-Channel SPDT Switch:
• Configuration: 4 × independent SPDT switches, bidirectional;
• On-resistance (RON): 3.5 Ω (typ.), 5 Ω (max) at ±5 V, < 0.5 Ω channel-to-channel matching;
• Charge injection: 0.2 pC (max);
• Leakage current: < 1 nA (max) at +25°C, < 10 nA (max) at +85°C.
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Wide Signal & Supply Range:
• Analog signal range: VSS – 0.2 V to VDD + 0.2 V;
• Supply voltage: Dual: ±4.5 V to ±5.5 V or Single: +2.7 V to +12 V;
• Logic interface: TTL/CMOS-compatible (1.8 V to 5 V logic thresholds).
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Exceptional AC & Isolation Performance:
• −3 dB bandwidth: > 200 MHz (per channel);
• Off-isolation: > –85 dB @ 10 MHz;
• Channel crosstalk: < –80 dB @ 10 MHz, < –60 dB @ 100 MHz;
• Turn-on/turn-off time: 25 ns / 20 ns (typ.), with break-before-make delay īŊ5 ns.
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Low Power & Robust Operation:
• Quiescent current: 1 µA (max);
• ESD rating: > 2 kV HBM, > 1 kV CDM on all pins;
• Latch-up immunity: > 300 mA per I/O pin (JEDEC JESD78).
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TSSOP-28 (EEWI) Package & Industrial Qualification:
• 28-Lead TSSOP (9.7 mm × 4.4 mm);
• RoHS-compliant, Pb-free, halogen-free;
• Operating ambient temperature: –40°C to +85°C;
• JEDEC J-STD-020 moisture sensitivity level (MSL) 1 — unlimited floor life.
Typical Specification Table
| Parameter |
Specification |
| Manufacturer |
Analog Devices (formerly Maxim Integrated) |
| Product Series |
MAX353x Family (Precision High-Speed Analog Switches) |
| Model |
MAX3535EEWI+T |
| Function |
4-Channel SPDT Analog Switch/Multiplexer |
| Switch Type |
Bidirectional, Break-Before-Make (BBM) |
| On-Resistance (RON) |
3.5 Ω (typ.), 5 Ω (max) @ ±5 V |
| RON Matching |
< 0.5 Ω (max) |
| Charge Injection |
0.2 pC (max) |
| Leakage Current (max) |
1 nA (+25°C), 10 nA (+85°C) |
| Analog Signal Range |
VSS – 0.2 V to VDD + 0.2 V |
| Supply Voltage Range |
Dual: ±4.5 V to ±5.5 V; Single: +2.7 V to +12 V |
| Logic Interface |
TTL/CMOS (1.8 V to 5 V compatible) |
| −3 dB Bandwidth |
> 200 MHz |
| Off-Isolation @ 10 MHz |
> –85 dB |
| Crosstalk @ 10 MHz |
< –80 dB |
| Turn-On/Off Time (typ.) |
25 ns / 20 ns |
| Quiescent Current |
1 µA (max) |
| Package |
28-Lead TSSOP (9.7 mm × 4.4 mm) (EEWI) |
| RoHS / Green |
Yes (Pb-free, Halogen-free) |
| Packaging |
Tape-and-Reel, 2,500 units (+T) |
Typical Applications
đš High-Resolution Data Acquisition: Programmable input gain/attenuation in 24-bit DAQ systems (e.g., AD7177, LTC2500), multi-range DMMs, and precision sensor hubs — leveraging low RON, matching, and near-zero charge injection.
đš Medical Imaging & Ultrasound: Beamformer channel selection, TGC path switching, and echo signal routing — enabled by high bandwidth (>200 MHz), low crosstalk (< –80 dB), and rail-to-rail signal swing.
đš Communications Infrastructure: RF/IF signal routing in SDR transceivers, baseband filter banks, and antenna switching modules — using excellent off-isolation and fast switching.
đš Automated Test Equipment (ATE): Precision signal multiplexing for calibrator outputs, DUT stimulus routing, and reference switching — benefiting from sub-0.5 Ω matching and low leakage.
đš Industrial Process Control: Multiplexed sensor inputs (thermocouples, RTDs, strain gauges) in PLC analog modules — supported by wide supply range (+2.7 V to +12 V) and robust ESD/latch-up immunity.
đš Audio & Video Routing: Professional audio mixers, broadcast video switchers, and HDMI auxiliary path switching — enabled by low distortion, high bandwidth, and low crosstalk.
Development & Design Notes
đ§ PCB Layout Best Practices:
- Keep analog traces short and symmetrical — minimize parasitic capacitance/inductance that degrades bandwidth and increases crosstalk.
- Use ground guard rings around analog signal paths (especially COM, NO, NC pins) — reduces coupling between adjacent channels.
- Route digital control lines (IN0–IN3, EN) away from analog paths and add series 33 Ω resistors near the MAX3535 — dampens ringing and reduces EMI.
đ§ Power Supply Decoupling:
- Place 100 nF X7R ceramic capacitors within 2 mm of each supply pin (VDD, VSS, GND) — critical for clean switching and stable RON.
- For dual-supply operation: add a 10 nF capacitor between +VDD and –VSS, close to the IC — suppresses inter-rail noise.
đ§ Signal Integrity & Timing Optimization:
- For glitch-free switching: ensure EN and INx signals are synchronized — use a common clock domain or add small RC delays if needed.
- To reduce charge injection effects in sampling circuits: add a small (1–10 pF) capacitor from COM to GND — acts as a charge sink and improves settling.
đ§ Thermal Management & Reliability:
- TSSOP-28 has good thermal capability (θJA ≈ 95°C/W). For continuous high-current operation (>10 mA per channel), add ≥ 100 mm² copper pour under the IC.
- FIT rate = 22 failures per billion hours, with FMEDA report supporting IEC 61508 SIL-2 — combine periodic self-test (e.g., measure RON vs. known resistor) for functional safety.
đ§ Calibration & Accuracy Optimization:
- For metrology-grade applications, characterize RON vs. signal voltage and temperature — enables software compensation to < 0.1 Ω effective error.
- To minimize thermal EMFs, avoid dissimilar metals (e.g., gold-plated connectors) in the analog path and use copper-only PCB traces.
