Texas Instruments MAX3221IPWR

Overview

MAX3221IPWR from Texas Instruments is a 3-V to 5.5-V single-driver, single-receiver RS-232 transceiver with ±15-kV HBM ESD protection on bus pins, 250-kbps data rate capability, automatic power-down (1 µA standby current), and integrated dual charge-pump generating ±5.5 V from a single supply-used in battery-powered industrial PCs and portable computing interfaces.

For engineers reviewing the MAX3221IPWR datasheet, MAX3221IPWR pinout, MAX3221IPWR application, or MAX3221IPWR equivalent, this page delivers verified technical context, validated pin functions, real-world timing behavior (tPLH/tPHL ≤ 150 ns), ESD robustness evidence, and direct alternative comparisons for RS-232 interface design and BOM optimization.

Technical Context

The MAX3221IPWR implements a dual-stage charge-pump architecture to generate ±5.5 V rails (V+ and V−) from 3.3 V or 5 V, enabling compliant RS-232 output levels (±5.4 V) without dual supplies. Its receiver features hysteresis (0.5 V) and input thresholds (±2.7 V valid, ±0.3 V invalid detection window), while the INVALID output signals bus activity status with 1 µs/30 µs propagation delays.

Power management is controlled via FORCEON/FORCEOFF logic inputs: automatic power-down activates when FORCEON = GND and FORCEOFF = VCC, disabling drivers and reducing ICC to 1 µA unless a valid RS-232 signal (>±2.7 V) is detected at RIN. EN pin independently enables/disables the receiver output (ROUT).

Key Specifications

Pinout & Package

TSSOP-16 (PW) package: 5.00 mm × 4.40 mm body, 0.65 mm pitch, surface-mount, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar RS-232 transceiver applications.

Compared with MAX3221IPWR, MAX3232CPWR adds channel count at the cost of pin compatibility and layout reuse, while SN65C3221PWR trades ultra-low-power sleep and bus-status signaling for raw speed - making MAX3221IPWR optimal for battery-constrained, single-port embedded systems requiring intelligent power management.

Availability

MAX3221IPWR is available at Aetrix Electronics and suitable for industrial PCs, handheld diagnostic tools, notebook docking stations, and network equipment console ports requiring stable component supply, long-term lifecycle support, and guaranteed RoHS-compliant sourcing.

Supply support for MAX3221IPWR 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and connectivity technologies, with over 50 years of innovation in precision interface solutions.

The MAX3221IPWR belongs to TI's RS-232 transceiver product line, engineered specifically for low-voltage, low-power, and high-ESD-resilience serial communication in portable and industrial edge devices.

FAQ

What is the maximum data rate supported by the MAX3221IPWR?

The MAX3221IPWR supports a maximum data signaling rate of 250 kbps under recommended operating conditions (CL = 1000 pF, RL = 3 kΩ). This meets TIA/EIA-232-F timing requirements for standard asynchronous serial communication and is validated across both 3.3 V and 5 V supply configurations. Operation beyond 250 kbps may result in non-compliant slew rates or timing violations.

Does the MAX3221IPWR require external charge-pump capacitors, and what values are specified?

Yes, the MAX3221IPWR requires four external 0.1 µF ceramic capacitors for charge-pump operation at 3.3 V supply (C1–C4). At 5 V supply, TI specifies C1 = 0.047 µF and C2–C4 = 0.33 µF. These capacitors enable generation of ±5.5 V internal rails from a single 3–5.5 V input, eliminating need for dual supplies. All capacitors must be placed close to their respective pins per layout guidelines.

How does the automatic power-down feature function in the MAX3221IPWR?

The MAX3221IPWR enters automatic power-down mode when FORCEON = GND and FORCEOFF = VCC. In this state, the driver is disabled and supply current drops to 1 µA typical - unless a valid RS-232 signal (|RIN| > ±2.7 V) is detected, which automatically re-enables the driver. The INVALID output indicates bus activity status and remains functional regardless of power-down state.

Is the MAX3221IPWR pin-compatible with other members of the MAX3221 family, such as MAX3221CDBR?

No - the MAX3221IPWR (TSSOP-16, PW package) and MAX3221CDBR (SSOP-16, DB package) share identical pin functions and electrical specifications but differ in physical dimensions, pitch (0.65 mm vs. 0.635 mm), and thermal characteristics. While schematic symbols are interchangeable, PCB footprints are not compatible due to distinct land patterns and body sizes (5.00 mm × 4.40 mm vs. 6.20 mm × 5.30 mm).

What is the purpose and behavior of the INVALID output on the MAX3221IPWR?

The INVALID output on the MAX3221IPWR is an active-high status signal indicating presence of valid RS-232 input at RIN. It goes high when |RIN| > ±2.7 V or transitions through ±0.3 V in <30 µs; it goes low when RIN remains within ±0.3 V for >30 µs (e.g., disconnected or powered-down peripheral). This signal enables host MCUs to enter low-power states and wake only on actual serial traffic - a key enabler for battery-operated designs using the MAX3221IPWR.