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Home > Products > Integrated Circuits (ICs) > Logic > Translators, Level Shifters

STMicroelectronics ST2129BQTR

Name: ST2129BQTR
Brand: STMicroelectronics
SKU: ST2129BQTR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: ST2129BQTR

Manufacturer:: STMicroelectronics

Category:: Translators, Level Shifters

Package:

Datasheet:: ST2129BQTR.pdf

Description:: IC TRANSLTR BIDIRECTIONAL 8QFN

Quantity:: RFQ Add To RFQ list

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Inventory:2,455

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Product details

Overview

ST2129BQTR from STMicroelectronics is a 2-bit dual-supply bidirectional level translator with push-pull outputs and no direction control pin. It operates across VL = 1.65–3.6 V and VCC = VL–5.5 V, supports up to 186 Mbps data rate (at VL = 3.0–3.6 V, VCC = 4.5–5.5 V), features 5.5 V-tolerant OE pin, and delivers ±2 kV HBM ESD protection. It enables voltage translation between low-voltage ASICs/PLDs (e.g., 1.8 V) and higher-voltage peripherals (e.g., 3.3 V or 5 V) in space-constrained mobile devices.

For engineers reviewing the ST2129BQTR datasheet, ST2129BQTR pinout, ST2129BQTR application, or ST2129BQTR equivalent, key selection criteria include bidirectional translation without direction pin, guaranteed AC performance across multiple VL/VCC combinations, tristate enable timing (tPZL ≤ 28 ns, tPHZ ≤ 50 ns), QFN8 package footprint (1.4 × 1.2 mm), and compatibility with 1.65–3.6 V logic domains interfacing to 3.3 V or 5 V buses.

Technical Context

The ST2129BQTR uses a totem-pole output architecture with internal weak pull-up/pull-down networks and one-shot transistors activated only during signal transitions-enabling automatic bidirectional level shifting without external direction control. Its dual-supply design isolates VL and VCC domains, allowing independent logic thresholds on each side.

Operation requires drivers capable of sourcing/sinking ≥1 mA to interface with the 4 kΩ weak buffer; resistive loads <50 kΩ are not recommended due to reliance on passive termination after transition. OE pin controls full I/O tristate (high-impedance) mode with 5.5 V tolerance, supporting mixed-voltage system power sequencing.

Key Specifications

Parameter	Value and Actual Design Meaning
Data rate	Up to 186 Mbps (measured at VL = 3.0–3.6 V, VCC = 4.5–5.5 V); ensures high-speed interconnect between low- and high-voltage domains
VL supply range	1.65 V to 3.6 V; supports 1.8 V and 2.5 V logic families as low-side interface
VCC supply range	VL to 5.5 V; enables translation to 3.3 V or 5 V systems without level-shifter cascading
Propagation delay	tPLH/tPHL ≤ 4.1 ns (I/OVL→I/OVCC, VL = 3.0–3.6 V, VCC = 4.5–5.5 V); maintains signal integrity in high-frequency digital links
OE pin tolerance	5.5 V tolerant (VOE max = 6.5 V absolute); allows direct connection to 5 V control logic without external resistor divider
ESD rating	±2 kV HBM on all pins; provides robustness against handling and board-level electrostatic discharge
Operating temperature	−40 °C to +85 °C; qualified for commercial and industrial ambient environments

Pinout & Package

ST2129BQTR is housed in a QFN8 package measuring 1.4 × 1.2 × 0.55 mm with 0.40 mm pitch and exposed thermal pad. The package supports automated assembly and offers low thermal resistance for power-efficient operation in compact layouts.

Pin/Terminal	Circuit Role	Design Meaning
1 (VL)	Low-side supply input	Sets logic threshold for I/OVL pins; must be ≥1.65 V and ≤ VCC
2 (I/OVL1)	Bidirectional low-voltage I/O	Translates signals between VL domain and VCC domain; no direction pin required
3 (I/OVL2)	Bidirectional low-voltage I/O	Second independent channel matching I/OVL1 functionality
4 (GND)	Ground reference	Common return path for both supply domains; must be connected to system ground plane
5 (OE)	Output enable control	Active-low; drives all I/Os into high-impedance state when low; 5.5 V tolerant
6 (I/OVCC2)	Bidirectional high-voltage I/O	Translates signals between VCC domain and VL domain; shares same architecture as I/OVL pins
7 (I/OVCC1)	Bidirectional high-voltage I/O	First high-voltage channel; pairs with I/OVL1 for full 2-bit translation
8 (VCC)	High-side supply input	Sets logic threshold for I/OVCC pins; must be ≥ VL and ≤ 5.5 V

Key Features

Feature	Design Value
No direction control pin	Enables automatic bidirectional translation using internal one-shot transistor switching-eliminates PCB routing and timing constraints of direction signal
Push-pull output stage	Delivers rail-to-rail output swing on both sides without external pull-ups, reducing BOM count and improving rise/fall times
Tristate enable (OE)	Single-pin global disable of all four I/Os; supports bus isolation during power sequencing or sleep modes
Wide dual-supply range	VL = 1.65–3.6 V and VCC = VL–5.5 V covers common interface combinations: 1.8 V ↔ 3.3 V, 2.5 V ↔ 5 V, 3.3 V ↔ 5 V
Small QFN8 footprint	1.4 × 1.2 mm area saves >60% board space vs. SOIC-8; compatible with fine-pitch SMT assembly

Applications

Mobile Baseband Interface

Wearable Sensor Hub

Use Scenario: Connecting an ultra-low-power 1.8 V sensor hub MCU to a 3.3 V display driver IC in a smartwatch.

IC Role / Device Role / Timing Role: Bidirectional level translator enabling SPI clock/data lines to cross voltage domains without direction arbitration overhead.

Use Value: Eliminates need for two separate unidirectional translators or GPIO-controlled direction logic, reducing component count and layout complexity.

Use Scenario: Interfacing a 2.5 V biometric sensor array to a 5 V host processor in a fitness tracker.

IC Role / Device Role / Timing Role: Dual-channel translator handling I²C SDA/SCL lines with guaranteed 144 Mbps capability at VL = 3.0–3.6 V, ensuring glitch-free communication during burst reads.

Use Value: Maintains I²C timing compliance (rise/fall time ≤1.5 ns) while supporting 5 V-tolerant OE for seamless integration into existing 5 V control infrastructure.

Industrial PLC I/O Module

Automotive Infotainment Debug Port

Use Scenario: Level-shifting UART TX/RX between a 3.3 V microcontroller and legacy 5 V RS-232 transceiver in a programmable logic controller.

IC Role / Device Role / Timing Role: Provides isolated, noise-immune translation with ±2 kV HBM protection on all pins-critical for field-deployed equipment.

Use Value: Enables direct connection without external ESD diodes or series resistors, simplifying certification for IEC 61000-4-2 Level 2.

Use Scenario: Adapting debug signals (SWDIO/SWCLK) from a 1.8 V ARM Cortex-M core to a 3.3 V JTAG debugger pod in automotive head unit development.

IC Role / Device Role / Timing Role: Translates high-speed debug protocol with sub-5 ns propagation delay and <28 ns output enable-preserving trace synchronization accuracy.

Use Value: Supports real-time SWD trace capture without introducing timing skew or requiring additional buffering stages.

Equivalent & Alternatives

The following parts are listed as comparable options for similar bidirectional level translation applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
TXS0102DCUR	2-bit auto-direction sensing; lower max data rate (60 Mbps); requires minimum 1 µA drive current on both sides	Designed for open-drain I²C; lacks 5.5 V-tolerant OE; not suitable for push-pull UART/SPI	Select when cost-sensitive I²C translation is needed and 5 V OE tolerance is unnecessary
SN74AVC2T244RSWR	2-bit dual-supply buffer with direction pin; higher drive strength (24 mA); no automatic bidirectionality	Requires external direction control logic; better for high-current loads but adds routing and timing complexity	Select when driving heavy capacitive loads (>30 pF) or when precise direction timing control is required

Compared with TXS0102DCUR, ST2129BQTR delivers 3× higher data rate and 5.5 V OE tolerance for mixed-voltage control; versus SN74AVC2T244RSWR, it eliminates direction pin routing and associated timing constraints-reducing PCB layer count and firmware overhead in compact portable designs.

Availability

ST2129BQTR is available at Aetrix Electronics and suitable for mobile device interfaces, wearable sensor hubs, industrial PLC I/O modules, and automotive debug port adapters requiring stable component supply, consistent QFN8 packaging, and production-grade qualification.

Supply support for ST2129BQTR 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, digital, and mixed-signal ICs for automotive, industrial, and consumer markets.

The ST2129B belongs to ST's level translation product line, engineered specifically for space-constrained, multi-voltage embedded systems where automatic bidirectional signal conversion and minimal external components are critical design requirements.

FAQ

What is the maximum allowable voltage difference between VL and VCC?

The datasheet specifies VCC must be ≥ VL and ≤ 5.5 V, with no explicit ΔV limit-but absolute maximum ratings define VL ≤ 4.6 V and VCC ≤ 6.5 V. Therefore, the maximum safe differential is 6.5 V − 1.65 V = 4.85 V, provided both supplies remain within their respective absolute max limits and recommended operating ranges. Exceeding VL = 3.6 V or VCC = 5.5 V invalidates AC performance guarantees.

Can ST2129BQTR translate between 1.2 V and 3.3 V logic?

No. VL minimum is 1.65 V per Table 5 (Recommended Operating Conditions). Attempting 1.2 V on VL violates specification, risks unreliable high-level detection (VIHL = 0.8 × VL = 0.96 V), and may cause excessive quiescent current or latch-up. For 1.2 V interfaces, consider ST2129B's successor family or discrete FET-based solutions.

Is the QFN8 package lead-free and RoHS-compliant?

Yes. ST documents ECOPACK® compliance in Section 7, confirming the ST2129BQTR meets RoHS Directive 2011/65/EU and REACH SVHC requirements. The QFN8 package uses matte tin (Sn) termination with no lead, antimony, or brominated flame retardants-verified via ST's public ECOPACK database and material declarations.

Does ST2129BQTR require external pull-up resistors on I/O lines?

No. Its totem-pole output architecture provides active drive in both logic states, eliminating need for external pull-ups. However, the datasheet cautions against resistive loads <50 kΩ because post-transition state retention relies on internal 4 kΩ weak buffers-external pull-ups would conflict with this design and degrade speed or cause contention.

ST2129BQTR Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Translator Type:: Voltage Level

Channel Type:: Bidirectional

Number of Circuits:: 1

Channels per Circuit:: 2

Voltage - VCCA:: 1.65 V ~ 3.6 V

Voltage - VCCB:: 1.65 V ~ 5.5 V

Input Signal:: -

Output Signal:: -

Output Type:: Push-Pull, Tri-State

Data Rate:: 144Mbps

Operating Temperature:: -40°C ~ 85°C (TA)

Grade:: -

Qualification:: -

Features:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-UFQFN

ST2129BQTR FAQ

1.How can I place an order for ST2129BQTR through Aetrix?

Please submit a Request for Quotation (RFQ) for ST2129BQTR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for ST2129BQTR reliable?

The price and inventory of ST2129BQTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ST2129BQTR is usually 5 days.

3.What payment methods are accepted for ST2129BQTR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ST2129BQTR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for ST2129BQTR?

ST2129BQTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your ST2129BQTR order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for ST2129BQTR?

For technical support, including ST2129BQTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ST2129BQTR requirements.

6.How does Aetrix verify that ST2129BQTR is sourced from the original manufacturer or authorized distributors?

All ST2129BQTR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that ST2129BQTR meets industry standards.

7.What is the process for return or replacement of ST2129BQTR?

All ST2129BQTR units undergo pre-shipment inspection (PSI). If there is an issue with ST2129BQTR, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The ST2129BQTR part is unused and in its original packaging.

Return procedure for ST2129BQTR:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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