Analog Devices Inc./Maxim Integrated MAX9643UATA+

Overview

The MAX9643UATA+ from Maxim Integrated is a unidirectional high-side current-sense amplifier with 10V/V fixed gain, 10MHz signal bandwidth, 130µV (max) input offset voltage, and -1.5V to +60V input common-mode range, designed for precision DC-DC converter control loops in industrial power supplies.

For engineers reviewing the MAX9643UATA+ datasheet, MAX9643UATA+ pinout, MAX9643UATA+ application, or MAX9643UATA+ equivalent, this device supports high-voltage, high-speed current monitoring where low VOS, wide VCM, true ground-referenced output, and tight gain error are critical for efficiency and accuracy in aggressive switching environments.

Technical Context

The MAX9643UATA+ employs a proprietary high-speed complementary BiCMOS SOI process enabling simultaneous high-voltage operation (60V VCM), fast transient response (100ns saturation recovery), and ultra-low input offset drift. Its internal 250kHz charge pump generates a negative rail to bias both input and output stages, enabling sub-ground common-mode operation and true 0V output swing.

This architecture eliminates crossover inaccuracies found in dual-stage input designs and ensures stable CMRR (110dB min over full temperature range) and PSRR (100dB min) across its 2.7V–36V supply range - critical for maintaining measurement integrity in noisy, high-dV/dt power-supply control paths.

Key Specifications

Pinout & Package

The MAX9643UATA+ is housed in an 8-pin TDFN-EP package (2mm × 3mm, 0.5mm pitch) with exposed pad thermally and electrically connected to GND. This compact, thermally efficient package supports high-density PCB layouts in space-constrained power modules.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-speed, high-voltage current-sense amplifier applications.

Compared with the MAX9643UATA+, the INA240A1QDGKRQ1 provides tighter offset but sacrifices bandwidth for automotive robustness, while the MAX40056ATA+T extends VCM to 76V but omits sub-ground capability - making the MAX9643UATA+ optimal for industrial 60V systems needing both speed and ground-penetrating sensing.

Availability

MAX9643UATA+ is available at Aetrix Electronics and suitable for industrial power supplies, GSM base station power systems, high-brightness LED drivers, and H-bridge motor controllers requiring stable component supply, long-term lifecycle support, and guaranteed RoHS-compliant sourcing.

Supply support for MAX9643UATA+ 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 power-management ICs for demanding industrial, communications, and computing applications.

The MAX9643 product line targets high-performance current sensing in switching power supplies, delivering speed, accuracy, and high-voltage tolerance through proprietary BiCMOS SOI process technology and integrated charge-pump architecture.

FAQ

What is the maximum input common-mode voltage supported by the MAX9643UATA+?

The MAX9643UATA+ supports an input common-mode voltage range of -1.5V to +60V across its full operating temperature range. This specification holds for all VCC values from 2.7V to 36V, enabling reliable high-side sensing even when the monitored rail is shorted to ground or operating near 60V. The -1.5V lower limit is enabled by the internal charge pump, and exceeding it requires limiting input current to ≤5mA via external series resistors.

Does the MAX9643UATA+ require external passive components for basic operation?

Yes, the MAX9643UATA+ requires three external 1µF ceramic capacitors for stable operation: one between CP1 and CP2 (flying capacitor), one from VEE to GND (charge-pump filter), and one from VCC to GND (supply bypass). These are mandatory per the datasheet to ensure low-noise performance, proper charge-pump regulation, and supply decoupling - omitting any compromises accuracy, bandwidth, or startup reliability of the MAX9643UATA+.

How does the charge pump in the MAX9643UATA+ improve system-level design?

The internal 250kHz charge pump in the MAX9643UATA+ generates a negative bias rail that enables two key system advantages: first, it extends the input common-mode range to -1.5V, allowing sensing during rail collapse or reverse faults; second, it biases the output stage to deliver true 0V output swing, eliminating level-shifters when interfacing with low-voltage ADCs. This reduces BOM count and improves signal integrity in the MAX9643UATA+ signal chain.

Can the MAX9643UATA+ be used in bidirectional current-sensing applications?

No, the MAX9643UATA+ is explicitly a unidirectional current-sense amplifier optimized for high-side sensing of forward current only. Its architecture and pinout (RS+, RS-) do not support polarity reversal or negative current measurement. For bidirectional applications, designers must select purpose-built devices such as the MAX40056 (bidirectional, 76V VCM) or INA229 (digital output, ±163.84mV full-scale), as the MAX9643UATA+ lacks the internal circuitry to resolve current direction.

What is the guaranteed gain error specification for the MAX9643UATA+ over temperature?

The MAX9643UATA+ guarantees a gain error of 0.6% maximum over the full operating temperature range of -40°C to +125°C. At +25°C, the typical gain error is 0.06%, with a maximum of 0.5%. This tight tolerance ensures consistent current-to-voltage scaling across industrial thermal environments, directly supporting accurate load monitoring and protection functions in systems using the MAX9643UATA+.