Analog Devices Inc./Maxim Integrated MAX1444EHJ

Overview

MAX1444EHJ from Maxim Integrated is a 10-bit, 40Msps pipelined analog-to-digital converter optimized for low-power, high-dynamic-performance imaging and communications systems. It features fully differential 400MHz -3dB input bandwidth, 59.5dB SNR at 20MHz input, 74dBc SFDR, single 3.0V supply operation, and an integrated 2.048V precision bandgap reference. It serves as the front-end digitizer in ultrasound and CCD imaging systems.

For engineers reviewing the MAX1444EHJ datasheet, MAX1444EHJ pinout, MAX1444EHJ application, or MAX1444EHJ equivalent, key selection considerations include its 5.5-cycle latency, CMOS-compatible three-state parallel outputs (1.7V–3.6V OVDD), differential input flexibility, internal reference accuracy (±1%, 60ppm/°C), and extended industrial temperature range (-40°C to +85°C).

Technical Context

The MAX1444EHJ implements a 10-stage, 1.5-bit-per-stage pipelined architecture with digital error correction and a fully differential track-and-hold amplifier. Sampling occurs on the falling edge of the 40MHz clock, with output data valid on the rising edge after 5.5 clock cycles of latency.

Its analog input path supports both differential and single-ended configurations, with common-mode voltage set to VDD/2 and ±1.0V differential input range. The internal reference structure allows three operating modes: internal (REFOUT→REFIN), buffered external (voltage applied to REFIN), or unbuffered external (REFIN = GND, REFP/REFN/COM driven externally).

Key Specifications

Pinout & Package

MAX1444EHJ is housed in a 32-pin TQFP package (5mm × 5mm, 0.8mm pitch) with exposed pad for thermal dissipation. Pin assignments are validated per Maxim's official pin configuration diagram (Rev 3, 8/10).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-speed ADC applications.

Compared with MAX1444EHJ, MAX1446EHJ delivers higher speed with identical footprint and reference flexibility, while ADS5271IPFP trades internal reference and CMOS outputs for LVDS channel synchronization-making MAX1444EHJ optimal for cost-sensitive, single-channel, self-contained digitizer designs.

Availability

MAX1444EHJ is available at Aetrix Electronics and suitable for ultrasound imaging, CCD sensor interfaces, and baseband digitization requiring stable component supply across industrial temperature ranges and long production lifecycles.

Supply support for MAX1444EHJ 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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, medical, and communications markets.

The MAX1444 product line was designed specifically for low-power, high-SNR digitization in portable and fixed medical imaging systems and broadband communications infrastructure where thermal budget and dynamic range are critical.

FAQ

What is the maximum clock frequency supported by the MAX1444EHJ?

The MAX1444EHJ supports a maximum clock frequency of 40MHz, as specified in its absolute maximum ratings and electrical characteristics. Operation beyond this frequency is not guaranteed and may degrade SNR, SFDR, or cause timing violations. The device achieves its rated 59.5dB SNR and 74dBc SFDR only at or below 40MHz with proper clock signal integrity (low jitter, <2ns edge rates). Exceeding 40MHz risks missing codes or increased aperture jitter, directly impacting digitized signal fidelity in ultrasound or CCD applications.

Does the MAX1444EHJ require an external reference voltage?

No, the MAX1444EHJ does not require an external reference voltage because it integrates a precision 2.048V bandgap reference with ±1% initial accuracy and 60ppm/°C temperature coefficient. The internal reference can be used directly by connecting REFOUT to REFIN, or it can be scaled via resistor divider for custom full-scale ranges. External reference is optional-only needed when higher accuracy, different voltage range, or system-level calibration is required. Using the internal reference simplifies layout and reduces BOM count for MAX1444EHJ-based designs.

How does the power-down mode function on the MAX1444EHJ?

The MAX1444EHJ enters power-down mode when the PD pin is driven high, reducing analog supply current to 4–15µA and digital supply current to 1–20µA. Wake-up time from power-down is 1.7µs, after which full performance resumes. During power-down, the digital outputs remain in high-impedance state if OE is also high. This mode is essential for battery-powered ultrasound probes or intermittent CCD readout, where duty-cycled operation saves >99% of active power without requiring re-initialization or recalibration of the MAX1444EHJ.

What is the purpose of the COM pin on the MAX1444EHJ?

The COM pin on the MAX1444EHJ provides the common-mode voltage reference (VDD/2) for the fully differential analog input stage. It serves as the bias point for IN+ and IN- inputs and must be bypassed to GND with a >0.1µF capacitor. In single-ended operation, the signal source connects to IN+, and IN- ties to COM. In differential mode, COM remains at VDD/2 and defines the center of the ±1.0V input range. Its buffered, low-impedance output ensures stable common-mode rejection and minimizes distortion-critical for maintaining 74dBc SFDR in MAX1444EHJ applications.

Can the MAX1444EHJ interface directly with a 1.8V FPGA I/O bank?

Yes, the MAX1444EHJ can interface directly with a 1.8V FPGA I/O bank using its OVDD supply pin. The D9–D0 outputs are CMOS-compatible and operate with OVDD programmable from 1.7V to 3.6V. When OVDD = 1.8V, VOH ≥ 1.6V and VOL ≤ 0.2V meet standard 1.8V LVTTL/LVCMOS thresholds. No level shifter is needed, reducing component count and signal integrity risk. Ensure OE is controlled synchronously with FPGA logic and that digital ground (OGND) is properly decoupled to prevent noise coupling into the MAX1444EHJ analog section.