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STMicroelectronics L6788ATR
- Part No.:
- L6788ATR
- Manufacturer:
- STMicroelectronics
- Category:
- Special Purpose Regulators
- Package:
- 40-VFQFN Exposed Pad
- Datasheet:
-
L6788ATR.pdf
- Description:
- IC REG DRIVER GPU 3OUT 40VFQFPN
- Quantity:
- Payment:
- Shipping:
Inventory:5,976
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Product details
Overview
L6788ATR from STMicroelectronics is a 3-phase synchronous buck controller with integrated high-current gate drivers, designed for GPU core voltage regulation. It supports 1/2/3-phase operation, delivers ±2% output voltage accuracy up to 1.35 V via serial/parallel VID, and features full differential current sensing, remote voltage sensing, and an embedded 5 V LDO regulator. Used in high-current DC-DC converters for discrete and integrated graphics cards.
For engineers reviewing the L6788ATR datasheet, L6788ATR pinout, L6788ATR application, or L6788ATR equivalent, key selection criteria include phase self-detection capability, programmable switching frequency (200–800 kHz), thermal monitoring via TCS pin, droop control via RT/DROOP, and robust OCP with average-current and per-phase thresholds.
Technical Context
The L6788ATR implements adaptive anti-cross-conduction logic across three independent PWM channels, each with dedicated high-side (UGATEx/BOOTx) and low-side (LGATEx) driver outputs. Its control loop uses a 15 MHz GBWP error amplifier with COMP output driving external RC compensation networks, supporting precise transient response and droop-based current sharing.
It integrates digital SMBus interface (SCL/SDA) for real-time power management configuration and monitoring, while analog inputs (VID0/VID1, R1/R2/R3, IREF) enable hardware-programmable voltage tables. Thermal protection operates via dual-threshold comparison of TCS pin voltage (1.500 V warning / 2.500 V shutdown) against PTC network output.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Phases | Configurable 1-, 2-, or 3-phase operation with automatic phase detection and startup sequencing. |
| Output Voltage Range | 0.800–1.350 V with ±2% accuracy; set via serial VID (SMBus) or parallel VID (R1/R2/R3 + IREF). |
| Switching Frequency | 200–800 kHz, programmable via RT/DROOP pin resistor; default 200 kHz when floating. |
| Current Sensing | Full differential sensing per phase (CS1±/CS2±/CS3±); total current monitoring via IOUT/OCP pin. |
| OCP Thresholds | Average OCP at 1.700 V on IOUT/OCP; per-phase OCP at 33 µA on CSx− pins. |
| Thermal Monitoring | Dual-threshold TCS input: 1.500 V triggers VR_HOT warning; 2.500 V initiates thermal shutdown. |
| Integrated LDO | 5 VCC output (20 mA max, ±2.5%) powered from VCC1_IC ≥ 8 V; used for biasing external circuitry. |
Pinout & Package
VPQFN40 package: 6 × 6 mm body, 0.5 mm pitch, exposed thermal pad (PGND-connected). Designed for high-power density GPU VRM layouts with optimized thermal dissipation via 16 vias under the pad.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BOOT1–BOOT3 | HS driver bootstrap supply | Capacitively coupled to PHASEx; enables high-side N-MOSFET drive; supports Vin detection. |
| UGATE1–UGATE3 | HS MOSFET gate driver output | Drives gate of external high-side FETs; requires series gate resistor for EMI/power optimization. |
| LGATE1–LGATE3 | LS MOSFET gate driver output | 12 V-tolerant output; drives low-side FET gates; referenced to PGND. |
| CS1±–CS3± | Differential current sense inputs | Measure inductor DCR voltage drop per phase; enable per-phase and total current protection. |
| VSEN / FBRTN | Remote output voltage sensing | VSEN connects to load positive; FBRTN to load ground - enables Kelvin sensing for <±2% regulation. |
| IREF / R1–R3 | Analog VID reference & scaling | IREF fixed at 1.240 V; R1/R2/R3 set power-play table voltages via 100 µA current mirror. |
| TCS / VR_HOT/EN | Thermal monitor input / system enable | TCS reads PTC voltage; VR_HOT/EN acts as enable input (1.3 V threshold) and open-drain thermal alert. |
| SCL / SDA | SMBus interface | Supports bidirectional communication for dynamic voltage/frequency scaling and telemetry readback. |
Key Features
| Feature | Design Value |
|---|---|
| Phase self-detection | Automatically identifies active phases during startup without external configuration; ensures safe multi-phase ramp-up. |
| LSLess startup | Enables controlled startup into pre-biased output rails without reverse current flow or instability. |
| Droop control | Programmable via RT/DROOP pin; implements output impedance emulation for accurate current sharing across phases. |
| Advanced thermal management | Combines die temperature sensing (T_HOT = T_SHUTDOWN − T_DELTA) and external PTC-based board-level monitoring. |
| Full protection suite | Includes OVP (140% VREF), UVP (50% VREF), per-phase and average OCP, thermal shutdown, and latchable POK fault signaling. |
Applications
| Graphics Card GPU Supply | High-Performance CPU Core VRM |
|---|---|
|
Use Scenario: Regulating core voltage for discrete NVIDIA/AMD GPUs requiring rapid load transients and tight voltage tolerance. IC Role / Device Role / Timing Role: Primary 3-phase buck controller managing gate drive, current sensing, thermal monitoring, and SMBus telemetry for GPU power delivery. Use Value: Enables ±2% output accuracy at 1.35 V with 200–800 kHz switching, supporting GPU power play states and dynamic voltage scaling. |
Use Scenario: Delivering >100 A core power to high-end desktop/server CPUs with multi-phase current sharing requirements. IC Role / Device Role / Timing Role: Multi-phase controller with per-phase current balancing, droop control, and differential remote sensing for stable rail regulation. Use Value: Full differential current sensing and programmable droop ensure <5% inter-phase current imbalance under 50 A/µs load steps. |
| AI Accelerator Board Power | Workstation GPU Compute Module |
|
Use Scenario: Powering FPGA-based AI inference accelerators with burst-mode workloads and strict thermal limits. IC Role / Device Role / Timing Role: Controller with thermal shutdown (2.500 V TCS threshold) and fast OCP response (<1 µs) to protect silicon under overload. Use Value: Dual-threshold TCS monitoring and 1.700 V average OCP threshold provide deterministic fault response before thermal runaway. |
Use Scenario: Compact, high-density GPU compute modules where PCB space and thermal performance are critical constraints. IC Role / Device Role / Timing Role: Integrated gate driver + controller in VPQFN40 reduces component count; exposed pad enables <35 °C/W θJA cooling. Use Value: Eliminates need for external driver ICs; 6×6 mm footprint supports ≤10 mm² per phase layout in space-constrained modules. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 3-phase GPU VRM controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ISL6367IRZ | Uses 3.3 V logic interface; lacks integrated 5 V LDO; requires external VDD bias for drivers. | Targeted at legacy server VRMs with fixed 3-phase topology; no phase self-detection. | Select when existing design uses 3.3 V control rails and external 5 V bias is already available. |
| RT8803AZSP | Supports up to 6 phases; no SMBus interface; relies solely on analog VID and GPIO control. | Optimized for cost-sensitive consumer motherboards; no remote thermal monitoring or droop programming. | Select for high-phase-count, non-telemetry applications where SMBus and TCS functionality are unnecessary. |
Compared with ISL6367IRZ and RT8803AZSP, the L6788ATR uniquely combines SMBus programmability, integrated 5 V LDO, dual-threshold thermal monitoring, and phase self-detection-making it optimal for next-generation GPU power with minimal external components and full telemetry support.
Availability
L6788ATR is available at Aetrix Electronics and suitable for graphics card GPU supply, high-performance CPU core VRMs, AI accelerator board power, and workstation GPU compute modules requiring stable component supply across extended production lifecycles.
Supply support for L6788ATR 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, specializing in power management, microcontrollers, and automotive ICs with broad industrial and computing portfolio coverage.
The L6788ATR belongs to ST's GPU/VRM controller product line, engineered specifically for high-current, multi-phase DC-DC conversion in graphics and compute-intensive applications demanding precision regulation and intelligent thermal protection.
FAQ
What is the function of the RT/DROOP pin?
The RT/DROOP pin sets the switching frequency (200–800 kHz) via an external resistor to AGND and simultaneously enables/disables the droop control function. When left floating, it defaults to 200 kHz operation with droop disabled. Connecting a resistor configures both parameters simultaneously using the same node - no separate control lines required.
How does phase self-detection work on the L6788ATR?
Phase self-detection occurs automatically during power-on reset by monitoring BOOTx and PHASEx voltage relationships. The controller detects which phases have functional external components (MOSFETs, inductors, bootstrap diodes) and configures itself for 1-, 2-, or 3-phase operation without firmware or external strapping. This eliminates manual configuration errors and ensures safe startup.
Can the L6788ATR operate with pre-biased outputs?
Yes - L6788ATR supports LSLess (Lossless) startup, allowing controlled ramp-up into pre-biased output rails. This prevents reverse current flow through low-side MOSFETs and avoids output voltage overshoot or instability, critical for hot-plug GPU modules and systems with shared power domains.
What is the role of the IREF and R1–R3 pins in voltage programming?
IREF provides a precise 1.240 V reference; connecting a 12.4 kΩ resistor to AGND sources 100 µA, mirrored to R1/R2/R3 pins. Each Rx pin voltage (VRx = 100 µA × Rx) sets one level of the 4-entry power-play table, enabling hardware-defined voltage states independent of SMBus communication.
L6788ATR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 40-VFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Applications:
- Driver, Next Generation GPU
- Voltage - Input:
- 10.8V ~ 13.2V
- Number of Outputs:
- 3
- Voltage - Output:
- 0.56V ~ 1.35V
- Operating Temperature:
- 0°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 40-VFQFPN (6x6)
L6788ATR FAQ
1.How can I place an order for L6788ATR through Aetrix?
Please submit a Request for Quotation (RFQ) for L6788ATR 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 L6788ATR reliable?
The price and inventory of L6788ATR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L6788ATR is usually 5 days.
3.What payment methods are accepted for L6788ATR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L6788ATR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for L6788ATR?
L6788ATR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your L6788ATR 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 L6788ATR?
For technical support, including L6788ATR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L6788ATR requirements.
6.How does Aetrix verify that L6788ATR is sourced from the original manufacturer or authorized distributors?
All L6788ATR 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 L6788ATR meets industry standards.
7.What is the process for return or replacement of L6788ATR?
All L6788ATR units undergo pre-shipment inspection (PSI). If there is an issue with L6788ATR, 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 L6788ATR part is unused and in its original packaging.
Return procedure for L6788ATR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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