Analog Devices Inc./Maxim Integrated MAX3100CEE+

Overview

MAX3100CEE+ from Maxim Integrated is a SPI/MICROWIRE-compatible universal asynchronous receiver-transmitter (UART) optimized for microcontroller-based systems. It integrates a crystal oscillator, 8-word FIFO, IrDA timing mode, and hardware/software shutdown - delivering up to 230 kbaud with 3.6864 MHz crystal, 150 µA operating current at 3.3 V, and 10 µA shutdown current. It enables isolated RS-232/RS-485 links and low-cost IR data communication in compact QSOP-16 packaging.

For engineers reviewing the MAX3100CEE+ datasheet, MAX3100CEE+ pinout, MAX3100CEE+ application, or MAX3100CEE+ equivalent, this page provides verified technical context, real-world interface constraints (e.g., Schmitt-trigger inputs, 25 mA TX/RTS sink capability), exact FIFO behavior under high-data-rate loads, IrDA SIR timing compliance, and validated alternatives for UART-in-SPI system upgrades.

Technical Context

The MAX3100CEE+ implements a full UART core with configurable 7-/8-bit word length, parity enable/disable, and 1–2 stop bits, all programmable via 16-bit SPI writes. Its baud-rate generator uses B0–B3 bits to select 16 division ratios, supporting standard rates from 300 to 230 kbaud with 1.8432 MHz or 3.6864 MHz crystals.

It features dual interrupt sources - receive activity detection during shutdown (RA bit) and framing error (FE bit) in normal operation - both maskable via RAM register. The IRQ output is open-drain, compatible with 5 V tolerant µC inputs, and cleared on Read Data operation.

Key Specifications

Pinout & Package

MAX3100CEE+ is housed in a 16-pin QSOP package (5.3 mm × 10.2 mm, 1.0 mm height) with lead-free/RoHS-compliant finish. Pin 1 is marked by a dot; pin numbering follows standard counter-clockwise orientation from top-left corner.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar UART bridging applications.

Compared with MAX3100CEE+, MAX3107EEE+ offers higher ESD tolerance and larger FIFO but sacrifices hardware shutdown and wide-voltage flexibility; SC16IS752IPW adds I²C support and GPIOs at the cost of larger footprint and non-QSOP packaging - making MAX3100CEE+ optimal for space-constrained, low-power SPI-only microcontroller interfaces.

Availability

MAX3100CEE+ is available at Aetrix Electronics and suitable for handheld instruments, intelligent instrumentation, UART-in-SPI systems, isolated RS-232/RS-485 interfaces, and low-cost IR data links requiring stable component supply across commercial temperature range (0°C to +70°C).

Supply support for MAX3100CEE+ 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 design house specializing in precision analog, mixed-signal, and high-reliability interface solutions for industrial, medical, and communications markets.

The MAX3100 product line was designed specifically to embed UART functionality into SPI-based microcontroller systems - eliminating parallel-bus UARTs and reducing µC pin count, PCB area, and firmware complexity in space- and power-sensitive applications.

FAQ

What is the maximum crystal frequency supported by the MAX3100CEE+?

The MAX3100CEE+ supports 1.8432 MHz and 3.6864 MHz crystals as specified in the datasheet. While X1 can accept an external square-wave clock up to 23.04 MHz (for 230.4 kbaud ÷ 16), the internal oscillator circuitry is characterized only for those two crystal frequencies. Using other crystals may result in baud-rate inaccuracy exceeding 1%, risking communication failure with standard UART peripherals.

Does the MAX3100CEE+ support true hardware flow control with RTS/CTS?

Yes, the MAX3100CEE+ supports hardware flow control: RTS is a software-controllable active-low output that can drive RS-485 driver-enable pins, and CTS is a dedicated active-low input monitored by the µC via register reads. However, automatic RTS toggling based on FIFO level is not implemented - RTS state must be managed explicitly by firmware to assert before transmission and deassert after completion.

Can the MAX3100CEE+ operate with a 5 V supply while interfacing to a 3.3 V microcontroller SPI bus?

Yes - the MAX3100CEE+ accepts VCC from +2.7 V to +5.5 V, and its SPI inputs (DIN, SCLK, CS, SHDN, CTS) have VIH = 0.7 × VCC and VIL = 0.3 × VCC. At VCC = 5 V, VIH = 3.5 V, so a 3.3 V µC's logic-high output (typically ≥3.0 V) may fall below guaranteed recognition threshold. Use level-shifting or ensure µC IO is 5 V tolerant; alternatively, operate MAX3100CEE+ at 3.3 V for guaranteed compatibility.

How does the MAX3100CEE+ handle framing errors during shutdown mode?

In shutdown mode, the RA/FE register bit functions exclusively as Receive Activity (RA), not Framing Error (FE). A transition on RX sets RA = 1 and asserts IRQ if RAM = 1 - enabling wake-on-RX. FE detection is disabled during shutdown. Upon exit from shutdown, the first received character may cause a framing error due to oscillator startup delay; this FE bit is cleared automatically upon receipt of the next properly framed character.

Is the MAX3100CEE+ pinout compatible with other MAX3100 variants like MAX3100CPD+?

No - the MAX3100CEE+ (QSOP-16) and MAX3100CPD+ (14-pin DIP) have different pin counts and incompatible pin mappings. For example, IRQ is on Pin 6 in QSOP but Pin 14 in DIP; X1/X2 positions differ; and DIP includes N.C. pins absent in QSOP. Board redesign is required when switching packages - refer to Pin Configurations section of datasheet Rev 2 for exact mapping per variant.