STUSB4531QTR - USB PD Sink Controller I2C QFN-16 | ST
MPN: STUSB4531QTR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.45 | $2.45 |
| 10 | $2.21 | $22.10 |
| 100 | $1.96 | $196.00 |
| 500 | $1.76 | $880.00 |
| 1,000 | $1.58 | $1,580.00 |
STUSB4531QTR Overview
A USB PD sink controller is a power management interface IC that implements the USB Type-C connector attach/detect state machine and the USB PD protocol on the CC (Configuration Channel) pins, allowing a powered device to request higher voltages and currents from a PD source. It sits in the system hierarchy between the physical USB-C receptacle and the downstream DC-DC converter or battery charger, translating the negotiated contract into VBUS connect/disconnect control and voltage selection signals.
Key features of the STUSB4531 include fully autonomous negotiation (autorun mode) that requires no software support, making it ideal for automatic high-power profile charging; a hybrid mode that allows an embedded host to override or monitor negotiation via the I2C interface; and always-on dead battery mode, which presents CC pull-down terminations even when the device is unpowered, so a fully depleted battery (SOC = 0%) can still be charged directly from the VBUS receptacle pins.
Technically, the STUSB4531 integrates the CC line termination logic, BMC transceivers, PD protocol engine, and NVM-based configuration in a single die. VBUS_EN_SNK provides the sink VBUS power-path enable output, and the GATE pin supports external NMOS VBUS switch control. The I2C interface exposes status registers, alert interrupts, and allows runtime PDO modification without reprogramming the NVM.
Typical applications include USB-C powered monitors, docks and hubs, battery-powered consumer devices requiring dead-battery charging, industrial equipment with USB-C power inputs, and any sink-only system that needs PD negotiation without a firmware investment. Designers should note that dead battery mode is always active on the QTR and BJR variants, ensuring source attach even with zero system power.
A key design consideration is that the device is powered directly from VBUS through the VDD pin, so layout should keep the VBUS sense and CC traces short and matched, and the VBUS_EN_SNK pin can be left unconnected if the power path is controlled elsewhere while negotiation still proceeds over CC.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for STUSB4531QTR — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with STUSB4531QTR (same form factor and footprint) — differing in Dead Battery Mode, Function, Package, RoHS Status.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
STUSB4531BJR
✅ Drop-In✓ In Stock
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View Datasheet →STUSB4531ATR
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
STUSB4531QTR Specifications
| Function | Standalone USB Type-C PD sink controller |
| Interface | I2C |
| Package | QFN-16 (3x3 mm) |
| Mounting Type | Surface Mount |
| Negotiated Voltage Profiles | 5V / 9V / 12V / 15V / 18V |
| Configurable PDOs | Up to 5 |
| Operating Modes | Autorun mode, Hybrid mode |
| Dead Battery Mode | Yes (always operating on QTR variant) |
| Configuration Memory | Internal non-volatile memory (NVM) |
| Application | USB Type-C sink (power receiving) devices |
| CC Termination | Rd pull-down presented when unpowered |
| VBUS Switch Control | VBUS_EN_SNK output, GATE pin for external NMOS |
| RoHS Status | Compliant |
STUSB4531QTR qfn-16 (3x3 mm) Pin Configuration Guide
Pin configuration for STUSB4531QTR (qfn-16 (3x3 mm) package). Pin numbering, functions, and connection diagrams are defined in the manufacturer datasheet. Refer to it for the exact footprint and soldering guidelines.
No detailed pinout data available for STUSB4531QTR.
Refer to the datasheet for full pin configuration.
Typical Applications
STUSB4531QTR is suitable for 6 applications: USB-C Powered Monitors and Displays, Battery-Powered Consumer Devices with Dead Battery Charging, Docks, Hubs and Multi-Port Accessories, Industrial Equipment with USB-C Power Input, Fast-Charging Power Banks (Sink Side), Development Boards and Reference Designs.
USB-C Powered Monitors and Displays
The STUSB4531QTR fits USB-C powered monitor designs because a monitor is a classic sink device that must negotiate up to 18V or higher power profiles from a laptop or dock source. Its five configurable PDOs stored in NVM let the monitor advertise exactly the profiles its backlight and main rails accept (for example 9V/12V/15V/18V), while the autorun mode closes the contract with zero firmware involvement, simplifying the display scaler BOM. Placed between the USB-C receptacle CC pins and the VBUS load switch (controlled via VBUS_EN_SNK or the GATE pin with an external NMOS), the IC guarantees the path only connects after a stable negotiated voltage is present. The I2C interface lets the scaler read the negotiated contract for on-screen-display reporting.
Recommended
Battery-Powered Consumer Devices with Dead Battery Charging
For earbuds cases, wearables, and portable accessories, the STUSB4531QTR's always-on dead battery mode is decisive: because the IC presents CC pull-down terminations even with the system battery fully depleted (SOC = 0%), any USB-C PD source recognizes the device and immediately supplies VBUS. The IC runs directly from the VBUS receptacle pins through VDD, independently of the application battery state, so charging can begin in any battery condition. After the charger IC boots the system, the I2C interface can renegotiate higher profiles (9V/12V/15V) to cut charge time. This removes the need for a separate always-on microcontroller or CC logic, saving quiescent power and board area in the 3x3 mm QFN-16 footprint.
Recommended
Docks, Hubs and Multi-Port Accessories
USB-C hubs and docks act as sinks on their upstream port while distributing power downstream. The STUSB4531QTR handles the upstream side by autonomously negotiating the highest available PDO (up to 18V in its configuration) with the host source, then asserting VBUS_EN_SNK to connect the negotiated rail to the hub's power distribution stage. Because negotiation is NVM-based, every unit ships with an identical, production-programmed power policy without firmware maintenance across product variants. The hybrid mode additionally lets the hub controller adjust sink capabilities at runtime - for example reducing requested power when downstream ports are heavily loaded - via simple I2C writes, giving docks adaptive power budgeting in a single compact controller.
Recommended
Industrial Equipment with USB-C Power Input
Industrial instruments, sensors and gateways increasingly adopt USB-C as the service power input. The STUSB4531QTR provides a rugged, firmware-free PD sink front end: it negotiates 5V to 18V contracts with phones, laptops or PD chargers, and its GATE pin drives an external NMOS to isolate the input rail until a valid contract exists, protecting sensitive internal DC-DC converters from raw VBUS transients. The always-operating dead battery mode guarantees the unit powers up from any USB-C charger even after complete storage discharge - a common field condition for tools kept in vehicles. Its QFN-16 3x3 mm package suits compact DIN-rail and handheld enclosures, and I2C status registers enable condition monitoring by the main MCU.
Recommended
Fast-Charging Power Banks (Sink Side)
A power bank contains both a sink path (charging its own cells from a PD source) and a source path (discharging to devices). The STUSB4531QTR implements the sink side: in dead battery mode it draws VBUS from any charger even with fully depleted cells, and in autorun mode it negotiates up to five PDOs so the bank can accept 9V/12V/15V fast-charge profiles matched to its charger IC maximum. VBUS_EN_SNK gates the charge input only after the voltage contract is stable, avoiding overstress of the input protection stage. The I2C bus lets the power bank's fuel-gauge MCU monitor the active contract and coordinate charge current, while the 3x3 mm QFN-16 conserves PCB area in slim form factors.
Recommended
Development Boards and Reference Designs
Evaluation and development boards benefit from the STUSB4531QTR because it delivers full USB-C PD sink capability with no firmware: engineers power a prototype at 9V/12V/15V/18V simply by configuring NVM once (or leaving ST defaults) and attaching a PD charger. The hybrid I2C mode is valuable during development, exposing attach/detach events, negotiated PDO, and error registers to the developer's MCU or USB-I2C probe for debugging power contracts. ST provides reference designs and application schematics in the STUSB4531 datasheet, covering the CC/VBUS network and external NMOS gate drive, so a working PD sink can be validated on a first-rev board with minimal external components.
Recommended
Recommended Products Summary
Engineering reference data for STUSB4531QTR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | STUSB4531BJR | STUSB4531ATR |
|---|---|---|---|
| Package | QFN-16 (3x3 mm) | QFN-16 (3x3 mm) - same | QFN-16 (3x3 mm) - same |
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics |
| Interface | I2C | I2C | I2C |
| Configurable PDOs | Up to 5 | Up to 5 | Up to 5 |
| Configuration Memory | Internal NVM | Internal NVM | Internal NVM |
| Operating Modes | Autorun + Hybrid | Autorun + Hybrid | Autorun + Hybrid |
Key Differentiators
- Firmware-free PD negotiation (vs MCU-based PD stacks (e.g., software PD on STM32))
- Always-on dead battery mode (vs STUSB4531ATR (family variant))
- Hybrid I2C control coexists with autonomy (vs STUSB4531BJR (drop-in sibling))
Design Notes
Keep the CC1/CC2 traces from the USB-C receptacle to the STUSB4531QTR short, matched in length, and routed away from high-di/dt switching nodes; the BMC signaling on CC lines is sensitive to coupling. Place the VBUS divider/sense network close to the VDD pin, and provide a local 1 uF plus 100 nF decoupling per the ST datasheet application schematic. Since the IC is powered from VBUS, verify the VDD pin never exceeds its absolute maximum during hot-plug transients on long cables.
The GATE pin drives an external NMOS for the VBUS power path; choose a MOSFET with a gate threshold compatible with the GATE drive level and a VDS rating above the maximum negotiated voltage with margin (18V PDOs suggest at least a 30V-rated FET). Alternatively, the VBUS_EN_SNK pin can drive a load-switch controller directly, or be left unconnected if the power path is managed elsewhere - per ST community guidance, negotiation still completes over CC regardless.
Remember dead battery mode is ALWAYS active on the STUSB4531QTR: the CC Rd pull-downs are presented even with the system fully unpowered, so a source will apply VBUS immediately on cable attach. Ensure downstream circuitry tolerates this inrush - gate the power path properly or size the load switch soft-start. Also, if your application requires configurable behavior at runtime, use hybrid mode over I2C rather than assuming the autorun/NVM policy can change without reprogramming.
Compliance Information
RoHS compliance inferred from distributor listing of this active ST part; formal REACH/material declarations available from the ST product page compliance documentation section.
