Analog Devices Inc./Maxim Integrated MAX4968AECM+

Overview

MAX4968AECM+ from Maxim Integrated is a 16-channel, high-voltage, bidirectional SPST analog switch with 18Ω typical on-resistance, ±100V analog signal range (210V_P-P), integrated 40kΩ bleed resistors per channel, and 25MHz serial interface. It operates with +10V V_PP, -200V V_NN, and +2.37V to +5.5V logic supply, targeting ultrasound transmit path switching in medical imaging systems.

For engineers reviewing the MAX4968AECM+ datasheet, MAX4968AECM+ pinout, MAX4968AECM+ application, or MAX4968AECM+ equivalent, key selection considerations include its 40kΩ integrated bleed resistors (vs. MAX4968), 210V_P-P analog range, 18Ω R_ON, -80dB off-isolation at 5MHz, and daisy-chainable 16-bit serial control for multi-probe probe multiplexing.

Technical Context

The MAX4968AECM+ integrates HVCMOS process technology to combine high-voltage bilateral MOS switches with low-power CMOS logic, enabling direct control of ±100V analog signals using only +10V V_PP-eliminating need for +100V supplies required by legacy alternatives. Its 16-bit shift register and transparent latch support daisy-chained configuration across multiple devices.

Each channel features matched 18Ω on-resistance (±3% matching), <2% R_ON flatness over full input range, and 9pF off-capacitance-critical for preserving pulse fidelity in 2–30MHz ultrasound burst transmission. The integrated 40kΩ bleed resistors discharge piezoelectric transducer capacitance between pulses, reducing settling time and echo interference.

Key Specifications

Pinout & Package

MAX4968AECM+ is housed in a 48-pin LQFP (7mm × 7mm) package with exposed pad for thermal management. All power and logic pins are internally decoupled via dedicated bypass capacitor pads.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage analog switching applications.

Compared with MAX4968ECM+, the MAX4968AECM+ adds integrated bleed resistors at no pinout or timing penalty-reducing bill-of-materials and improving echo fidelity. Versus MAX14803ETL+, it cuts V_PP from +100V to +10V, enabling smaller, cooler, and lower-cost power supplies without sacrificing voltage range or bandwidth.

Availability

MAX4968AECM+ is available at Aetrix Electronics and suitable for medical ultrasound imaging, industrial nondestructive testing (NDT), and high-voltage printer head control requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for MAX4968AECM+ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Maxim Integrated (now part of Analog Devices) designs precision analog, mixed-signal, and high-voltage ICs for demanding industrial, medical, and communications applications.

The MAX4968AECM+ belongs to Maxim's high-voltage analog switch product line, engineered specifically for ultrasound transmit multiplexing-delivering high linearity, low distortion, and integrated discharge capability in compact LQFP packages.

FAQ

What is the maximum analog signal voltage supported by the MAX4968AECM+?

The MAX4968AECM+ supports an analog dynamic signal range from V_NN to V_NN + 210V, enabling ±100V differential operation when V_NN = -100V. This 210V_P-P rating is validated for AC operation above 500kHz and applies across the full -40°C to +85°C temperature range. The device maintains linearity and low distortion within this range due to guaranteed R_ON flatness and low charge injection.

How do the integrated bleed resistors in the MAX4968AECM+ improve ultrasound system performance?

The MAX4968AECM+ integrates 40kΩ (typ) bleed resistors on each analog switch terminal to discharge capacitive loads-such as piezoelectric transducers-between transmit pulses. This reduces residual voltage that causes post-burst ringing and interferes with weak echo reception. In practice, this improves near-field image resolution and lowers artifact levels in medical ultrasound systems without requiring external discharge circuitry.

Is the MAX4968AECM+ pin-to-pin compatible with other Maxim high-voltage switches?

Yes, the MAX4968AECM+ is pin-to-pin compatible with the MAX14803 and Supertex HV2701. However, those parts require a +100V V_PP supply, whereas the MAX4968AECM+ operates from +10V V_PP. This compatibility allows drop-in replacement in existing layouts-but system-level power supply redesign is required to leverage the lower V_PP advantage of the MAX4968AECM+.

What serial interface protocol does the MAX4968AECM+ use, and how is daisy-chaining implemented?

The MAX4968AECM+ uses a 16-bit SPI-compatible serial interface with DIN, CLK, LE, CLR, and DOUT signals. Daisy-chaining is implemented by connecting the DOUT of one device to the DIN of the next, while sharing CLK, LE, and CLR across all devices. A single 16-bit write updates one device; cascading N devices requires 16×N clock cycles, enabling scalable control of large transducer arrays without additional GPIO resources.

Does the MAX4968AECM+ require specific power supply sequencing during startup?

No, the MAX4968AECM+ does not require strict supply sequencing. V_DD, V_PP, and V_NN may be powered in any order. However, LE must be held low during power-up to ensure proper initialization of the internal 16-bit latch and shift register. The device includes an internal power-on-reset circuit that sets all switches to the open (off) state at startup, providing fail-safe default behavior for safety-critical ultrasound systems.