The ESP32-WROOM-32U is a general-purpose Wi-Fi + Bluetooth + Bluetooth LE MCU module from Espressif Systems, designed for applications where an external antenna is required. Unlike the standard ESP32-WROOM-32D with its onboard PCB antenna, the 32U variant features a U.FL/IPEX connector for attaching an external antenna — making it the preferred choice for products housed in metal enclosures, shielded assemblies, or any deployment where the onboard antenna would be blocked or severely attenuated.
This version features 16MB (128Mbit) of SPI flash, the maximum storage configuration available for the WROOM-32U series. This expanded capacity is ideal for applications requiring extensive firmware images, large OTA update buffers, or substantial data storage for logging and configuration files.
At the core of the module is the ESP32-D0WD chip, featuring a dual-core Xtensa 32-bit LX6 microprocessor with an adjustable clock frequency from 80 MHz to 240 MHz. The two CPU cores can be individually controlled, and a low-power co-processor can monitor peripherals while the main cores are powered down — ideal for balancing performance and power consumption. The chip‘s sleep current is below 5 µA, making it suitable for battery-powered wearable electronics and low-power sensor networks.
The module supports Wi-Fi 802.11 b/g/n with data rates up to 150 Mbps and Bluetooth v4.2 (BR/EDR and BLE). Antenna output power reaches up to 20 dBm, ensuring maximum wireless range when paired with a suitable external antenna. The compact form factor (18 × 19.2 × 3.2 mm) is slightly smaller than the 32D variant due to the absence of the onboard antenna.
The module integrates a rich set of peripheral interfaces including SD card, UART, SPI, SDIO, I2C, LED PWM, motor PWM, I2S, IR, pulse counter, GPIO, capacitive touch sensor, ADC, DAC, and TWAI® (compatible with ISO 11898-1, i.e., CAN Specification 2.0). It operates from 3.0 to 3.6 V with an operating temperature range of -40°C to +85°C, and carries REACH/RoHS environmental certifications.
Product Status Note: The ESP32-WROOM-32U series is marked as NRND (Not Recommended for New Designs) by Espressif. For new product development, the ESP32-WROOM-32UE series is the recommended replacement, offering the same external antenna functionality with updated chip revisions and continued manufacturing support.
Development support is extensive, with official support for Espressif’s ESP-IDF and the Arduino IDE through the Arduino-ESP32 core. The module is suitable for both individual makers and businesses purchasing for product development, smart home devices, industrial automation, and applications requiring reliable wireless connectivity in challenging RF environments.
Features
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External U.FL/IPEX antenna connector — Ideal for metal enclosures and maximum-range applications
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ESP32-D0WD dual-core processor — Xtensa 32-bit LX6, up to 240 MHz, with adjustable frequency
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16MB SPI Flash — Maximum storage capacity for the WROOM-32U series, ideal for complex firmware and data logging
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Wi-Fi 802.11 b/g/n — Up to 150 Mbps data rate with 20 dBm output power
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Bluetooth v4.2 BR/EDR + BLE — Classic Bluetooth and Bluetooth Low Energy support
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Rich peripheral set — Up to 32 GPIOs, SD card, UART, SPI, I2C, I2S, PWM, ADC, DAC, capacitive touch, CAN-compatible TWAI®
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Ultra-low sleep current — Below 5 µA for battery-powered applications
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Compact footprint — 18 × 19.2 × 3.2 mm, smaller than the 32D due to no onboard antenna
Technical Specifications
| # | Parameter | Specification |
|---|---|---|
| 1 | Microcontroller | ESP32-D0WD, Xtensa dual-core 32-bit LX6 |
| 2 | Clock Speed | 80 – 240 MHz |
| 3 | Flash Memory | 16 MB (128 Mbit) SPI Flash |
| 4 | Wireless | Wi-Fi 802.11 b/g/n (150 Mbps), Bluetooth v4.2 BR/EDR + BLE |
| 5 | Antenna | U.FL / IPEX external connector |
| 6 | Operating Voltage | 3.0 – 3.6 V |
| 7 | Operating Temperature | -40°C to +85°C |
| 8 | Dimensions | 18.0 × 19.2 × 3.2 mm |
