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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Power Supply Controllers, Monitors

STMicroelectronics L6599AD

Name: L6599AD
Brand: STMicroelectronics
SKU: L6599AD
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: L6599AD

Manufacturer:: STMicroelectronics

Category:: Power Supply Controllers, Monitors

Package:: 16-SOIC (0.154", 3.90mm Width)

Datasheet:: L6599AD.pdf

Description:: IC RESONANT CONVRTR CTRLR 16SOIC

Quantity:: RFQ Add To RFQ list

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Product details

Overview

L6599AD from STMicroelectronics is a high-voltage resonant half-bridge controller IC designed for series-resonant LLC and LCC topologies. It delivers 50% complementary duty cycle, up to 500 kHz variable-frequency operation, 600 V-rail compatible high-side gate driver with integrated synchronous bootstrap diode, dual-level overcurrent protection (frequency-shift + latched shutdown), and burst-mode light-load efficiency-used in telecom SMPS and industrial AC-DC adapters.

For engineers reviewing the L6599AD datasheet, L6599AD pinout, L6599AD application, or L6599AD equivalent, key selection criteria include its fixed deadtime (0.2–0.4 µs), 2 V reference at RFmin pin, 0.8 V/1.5 V current sense thresholds, and SO16N package compatibility with creepage-critical high-voltage layouts.

Technical Context

The L6599AD implements a relaxation oscillator whose frequency is modulated by feedback current injected into the RFmin pin (2 V reference), enabling precise output voltage regulation via variable-frequency control. Its internal logic enforces strict 180° out-of-phase drive of high-side (HVG) and low-side (LVG) outputs with programmable deadtime (0.2–0.4 µs) to guarantee zero-voltage switching (ZVS) across load and line variations.

Protection architecture includes two-tier OCP: first-level frequency shift triggered at 0.8 V on ISEN (with 50 mV hysteresis), and second-level latched shutdown at 1.5 V; plus independent latched DIS input (>1.85 V threshold), LINE brownout detection (1.24 V threshold with 13 µA hysteresis current), and DELAY pin-based timed shutdown/restart (2 V/3.5 V/0.33 V thresholds).

Key Specifications

Parameter	Value and Actual Design Meaning
Oscillator freq. range	58.2–61.8 kHz typical base frequency; scalable to 500 kHz via external R_Fmin/C_F - sets resonant tank excitation point for ZVS operation.
Duty cycle	48–52% complementary output - ensures balanced conduction time for symmetrical half-bridge power transfer.
Deadtime	0.2–0.4 µs fixed internal delay - prevents shoot-through while enabling soft-switching at high dv/dt.
Current sense thresholds	0.8 V (frequency-shift OCP, 50 mV hysteresis); 1.5 V (latched shutdown) - enables staged overload response without false triggering.
High-side supply rating	V_BOOT = –1 to 618 V - supports direct bootstrap operation from 600 V bus without external HV diode.
Gate drive capability	±0.3 A source / +0.8 A sink (HVG/LVG) - drives 10–20 nF MOSFET gates at >300 kHz with <60 ns rise/fall times.
Reference voltage	2.0 V ±3% at RFmin pin - stable bias for optocoupler feedback network and frequency programming.

Pinout & Package

Package: SO16N (16-pin small outline, 150 mil width, 1.27 mm pitch), RoHS-compliant, rated for 150 °C junction temperature and 120 °C/W thermal resistance (T_A = 50 °C).

Pin/Terminal	Circuit Role	Design Meaning
1 (Css)	Soft-start timing capacitor node	Connects external C to GND and R to RFmin; controls startup frequency ramp slope and duration to limit inrush.
2 (DELAY)	OCP timeout timer	RC network sets max OCP duration before latch-off; charged by 150 µA current during ISEN > 0.8 V.
3 (CF)	Oscillator timing capacitor	Charged/discharged by current mirrored from RFmin; directly sets operating frequency.
4 (RFmin)	Min frequency & feedback interface	2 V reference input; resistor to GND sets min f_osc; optocoupler connects here for closed-loop regulation.
5 (STBY)	Burst mode enable	Compares feedback-derived voltage to 1.24 V; enters low-I_q idle state when below threshold.
6 (ISEN)	Average primary current sense	Filters sensed current for OCP; 0.8 V triggers frequency shift, 1.5 V triggers latched shutdown.
7 (LINE)	AC/DC brownout monitor	Resistor divider input; 1.24 V threshold with 13 µA hysteresis current ensures noise-immune line fault detection.
8 (DIS)	Latched disable	Active-high (>1.85 V) shutdown; requires V_CC recycle to reset - used for OTP/OVP hard faults.
9 (PFC_STOP)	PFC controller disable	Open-drain output pulled low during DIS, OCP latch, LINE overvoltage, or burst mode - synchronizes pre-regulator shutdown.
10 (GND)	Signal & low-side return	Common return for LVG driver and bias circuitry; must be isolated from high-dI/dt paths.
11 (LVG)	Low-side gate driver output	Drives lower MOSFET with –0.3 A / +0.8 A peak; actively pulled to GND during UVLO.
12 (V_CC)	IC supply input	8.85–16 V operating range; 10.7 V turn-on / 8.15 V turn-off UVLO with 2.55 V hysteresis.
13 (N.C.)	High-voltage spacer	No internal connection; maintains creepage distance between V_BOOT and GND pins per safety standards.
14 (OUT)	High-side floating ground	Return path for HVG current; layout critical - large dv/dt spikes must be minimized.
15 (HVG)	High-side gate driver output	Drives upper MOSFET referenced to OUT; same drive strength as LVG; internal pull-down to OUT during UVLO.
16 (V_BOOT)	High-side bootstrap supply	–1 to 618 V rating; fed by internal synchronous DMOS diode - eliminates external HV bootstrap diode.

Key Features

Feature	Design Value
Synchronous bootstrap diode	Integrated 150 Ω R_DS(on) DMOS replaces external fast-recovery diode - reduces BOM count and improves reliability at 600 V.
Non-linear soft-start	Frequency starts at max value and decays non-linearly to steady-state - prevents output overshoot and transformer saturation.
Two-level OCP with delay	First level shifts frequency to limit power; second level latches off after programmable delay - protects against sustained short circuits.
Burst mode at light load	Reduces quiescent current to 300–400 µA during idle - meets <300 mW no-load requirements for Energy Star Level VI.
Line sensing with hysteresis	1.24 V threshold with 13 µA hysteresis current - rejects line transients while ensuring clean brownout response.

Applications

Telecom SMPS

Industrial AC-DC Adapters

Use Scenario: 48 V input, 12 V/20 A output telecom rectifier operating at 300 kHz with >94% efficiency.

IC Role / Device Role / Timing Role: Resonant half-bridge controller providing 50% complementary drive, ZVS-enabling deadtime, and optocoupler-coupled voltage regulation.

Use Value: Enables high-power density design with reduced EMI and thermal stress due to soft-switching across full load range.

Use Scenario: 305 V_AC input, 24 V/10 A open-frame industrial power supply with PFC front-end.

IC Role / Device Role / Timing Role: Primary-side resonant controller interfacing with PFC_ST OP to coordinate pre-regulator shutdown during faults.

Use Value: Ensures system-level fault containment - simultaneous PFC and half-bridge shutdown prevents cascading failures.

LCD TV Power Supplies

Desktop PC PSUs

Use Scenario: 24 V/5 A standby rail and 192 V/2 A main rail for LED backlight in 55″ LCD TV.

IC Role / Device Role / Timing Role: Dual-output resonant controller using burst mode (STBY pin) to maintain <150 mW no-load consumption.

Use Value: Meets stringent EU CoC Tier 2 standby power requirements without auxiliary flyback winding.

Use Scenario: ATX-compliant 500 W PSU with LLC resonant converter delivering +12 V, +5 V, and +3.3 V rails.

IC Role / Device Role / Timing Role: Half-bridge controller managing ZVS transitions and coordinating with PFC via PFC_STOP signal.

Use Value: Delivers >92% efficiency at 50% load and <0.5% output ripple through precise frequency modulation.

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage resonant half-bridge controller applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
UCC256301 (Texas Instruments)	Integrated digital controller with built-in LLC resonant control algorithm; requires no external oscillator components.	Targets higher integration and adaptive deadtime tuning; lacks analog RFmin interface for optocoupler feedback.	Choose UCC256301 for designs requiring auto-tuning and digital diagnostics; retain L6599AD for cost-sensitive, analog-feedback systems.
IR3584M (Infineon)	Single-chip dual-channel LLC controller with integrated drivers; supports 2 MHz max frequency but only 400 V V_BOOT rating.	Designed for compact, high-density server PSUs; not suitable for 600 V bus applications like industrial AC-DC.	Choose IR3584M for space-constrained server supplies; select L6599AD where 600 V robustness and discrete driver flexibility are required.

Compared with UCC256301 and IR3584M, the L6599AD offers superior 600 V bootstrap tolerance, analog optocoupler interface simplicity, and proven field reliability in high-voltage industrial and telecom SMPS - making it optimal for cost-driven, high-reliability resonant converters.

Availability

L6599AD is available at Aetrix Electronics and suitable for telecom SMPS, industrial AC-DC adapters, and LCD TV power supplies requiring stable component supply, long-term lifecycle support, and traceable sourcing from authorized channels.

Supply support for L6599AD 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, analog, and microcontroller solutions for industrial, automotive, and consumer markets.

The L6599AD belongs to ST's high-voltage resonant controller product line, engineered specifically for efficient, reliable series-resonant half-bridge power conversion in energy-sensitive applications.

FAQ

What is the purpose of the N.C. pin (Pin 13) on the L6599AD?

Pin 13 is a no-connect spacer pin with no internal connection. Its sole function is to increase creepage distance between Pin 12 (V_CC) and Pin 14 (OUT) on the PCB, helping meet IEC/UL safety standards for 600 V-rated high-voltage designs. It must remain unconnected and should not be used for grounding or routing.

How does the L6599AD achieve zero-voltage switching (ZVS) in resonant half-bridge topologies?

The L6599AD guarantees ZVS by enforcing a fixed 0.2–0.4 µs deadtime between HVG and LVG transitions, allowing the resonant tank to reverse current and discharge MOSFET output capacitance before next turn-on. Combined with variable-frequency control locked to tank impedance, this ensures soft-switching across line and load variations without auxiliary circuits.

Can the L6599AD operate without an external PFC controller?

Yes - the PFC_ST OP pin (Pin 9) is optional and open-drain. If unused, it must be left unconnected or pulled high via resistor; the L6599AD functions fully as a standalone resonant controller. The PFC interface only activates when a compatible pre-regulator is present and requires coordinated shutdown.

What is the maximum allowable dV/dt on the OUT pin (Pin 14) and how is it managed?

The OUT pin is rated for up to 50 V/ns maximum slew rate. Layout best practices require minimizing loop area between OUT, HVG, and V_BOOT, using local ceramic decoupling (≥100 nF) at the bootstrap capacitor, and routing OUT as a dedicated low-inductance plane - not shared with power or signal returns - to suppress ringing and prevent false triggering.

L6599AD Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 16-SOIC (0.154", 3.90mm Width)

Packaging:: Tube

Product Status:: Active

Programmable:: Not Verified

Applications:: Resonant Converter Controller

Voltage - Input:: -

Voltage - Supply:: 8.85V ~ 16V

Current - Supply:: 3.5 mA

Operating Temperature:: 0°C ~ 105°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 16-SO

L6599AD FAQ

1.How can I place an order for L6599AD through Aetrix?

Please submit a Request for Quotation (RFQ) for L6599AD 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 L6599AD reliable?

The price and inventory of L6599AD are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L6599AD is usually 5 days.

3.What payment methods are accepted for L6599AD?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L6599AD transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for L6599AD?

L6599AD orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your L6599AD 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 L6599AD?

For technical support, including L6599AD datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L6599AD requirements.

6.How does Aetrix verify that L6599AD is sourced from the original manufacturer or authorized distributors?

All L6599AD 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 L6599AD meets industry standards.

7.What is the process for return or replacement of L6599AD?

All L6599AD units undergo pre-shipment inspection (PSI). If there is an issue with L6599AD, 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 L6599AD part is unused and in its original packaging.

Return procedure for L6599AD:

1.Submit a request within 90 days.

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

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