Analog Devices Inc./Maxim Integrated MAX122BCAG

Overview

The MAX122BCAG from Maxim Integrated is a 12-bit, BiCMOS sampling analog-to-digital converter (ADC) with integrated track/hold and -5V buried-zener reference, delivering 333ksps throughput at 5MHz clock, ±5V bipolar input range, and 69dB SINAD at +25°C for high-speed data acquisition in telecom and spectrum analysis systems.

For engineers reviewing the MAX122BCAG datasheet, MAX122BCAG pinout, MAX122BCAG application, or MAX122BCAG equivalent, this page provides verified timing behavior, TTL/CMOS-compatible µP interface timing, 24-pin SSOP package mapping, real-world dynamic performance limits (THD ≤ -75dB), and validated alternative options for signal-chain design continuity.

Technical Context

The MAX122BCAG implements successive approximation architecture with on-chip track/hold, achieving 350ns acquisition time and fixed 2.6µs conversion time (14 clock cycles at 5MHz). Its internal -5V reference exhibits ±25ppm/°C drift and supports external overdrive between -5.05V and -5.10V with ≥5mA sink capability.

It operates in five configurable modes-including continuous-conversion (MODE = DGND), full-control (MODE = VDD), and ROM mode-each with distinct INT/BUSY behavior and bus timing constraints. All digital I/Os are TTL/CMOS compatible, and data output format is two's-complement with 75ns access time.

Key Specifications

Pinout & Package

MAX122BCAG is housed in a 24-pin SSOP (Shrink Small Outline Package) with 0.635mm pitch, RoHS-compliant lead finish, and JEDEC MO-153 compliant footprint. Thermal derating is 8.00mW/°C above +70°C (640mW max at TA = +70°C).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit, medium-speed ADC applications.

Compared with MAX122ACAG+, the MAX122BCAG trades 0.25 LSB INL and 1dB SINAD for lower unit cost, while versus ADS7800U it delivers integrated reference and ±15V input tolerance at the expense of 333ksps maximum rate - making it optimal for cost-sensitive, robust telecom and instrumentation designs.

Availability

MAX122BCAG is available at Aetrix Electronics and suitable for digital signal processing, audio and telecom processing, and high-speed data acquisition requiring stable component supply across industrial temperature ranges (0°C to +70°C).

Supply support for MAX122BCAG 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 RF ICs for industrial, communications, and consumer applications.

The MAX120/MAX122 product line was designed for high-speed, precision data acquisition in systems requiring integrated track/hold and reference - targeting telecom infrastructure, test equipment, and real-time signal processing.

FAQ

What is the maximum clock frequency supported by the MAX122BCAG?

MAX122BCAG supports a maximum clock frequency of 5MHz, as specified in its Electrical Characteristics table. This limit ensures reliable 2.6µs conversion time and stable operation across the 0°C to +70°C temperature range. Exceeding 5MHz may cause timing violations, incomplete conversions, or degraded dynamic performance such as reduced SINAD or increased THD. The MAX122BCAG datasheet explicitly states fCLK = 0.1MHz to 5MHz, and this constraint is enforced by internal SAR timing margins and reference settling behavior.

Does the MAX122BCAG require external components for basic operation?

Yes, the MAX122BCAG requires external decoupling capacitors: 0.1µF ceramic capacitors on VDD and VSS pins referenced to DGND, and a 22µF electrolytic capacitor in parallel with a 0.1µF ceramic capacitor on the VREF pin referenced to AGND. These are mandatory for stable reference operation and noise suppression. No external track/hold capacitor or reference IC is needed - the device integrates both functions. The MAX122BCAG datasheet confirms "only external components needed are decoupling capacitors."

How does the MODE pin configuration affect the INT/BUSY output behavior of the MAX122BCAG?

When MODE is connected to VDD, INT/BUSY functions as an interrupt output: it goes low upon conversion completion and returns high after data is read. When MODE is open or tied to DGND, INT/BUSY acts as a busy flag: it goes low at conversion start and remains low until conversion completes and data is valid. This dual-mode behavior is confirmed in the MAX122BCAG Pin Description and Operating Modes sections, enabling flexible µP interface design without additional logic.

What is the guaranteed integral nonlinearity (INL) specification for the MAX122BCAG over temperature?

The MAX122BCAG guarantees ±1 LSB integral nonlinearity over its full operating temperature range of 0°C to +70°C, as documented in the Ordering Information and Electrical Characteristics tables. This value applies specifically to the MAX122BC/BE grade and is measured with VDD = +5V and VSS = -15V. It ensures monotonic 12-bit transfer function and absence of code ambiguities in closed-loop control or precision measurement applications using the MAX122BCAG.

Can the MAX122BCAG accept input voltages beyond its ±5V range without damage?

Yes, the MAX122BCAG analog input (AIN) is overvoltage tolerant to ±15V relative to AGND, as stated in the Absolute Maximum Ratings table. This protection applies even when the device is unpowered or in shutdown. However, normal operation remains limited to ±5V full-scale range; exceeding that during conversion causes clipping but not destruction. The ±15V rating is validated per Maxim's stress testing protocol and enables robust interfacing with industrial sensors and fault-prone signal paths using the MAX122BCAG.