STMicroelectronics L6590ED

Overview

L6590ED from STMicroelectronics is a monolithic off-line switching regulator IC integrating a 700 V lateral power MOSFET, 65 kHz fixed-frequency oscillator, and 2.5 V ±2% internal reference, designed for flyback, boost, and forward AC-DC converters delivering up to 15 W. It features non-dissipative start-up, standby mode (22 kHz), and cycle-by-cycle overcurrent protection.

For engineers reviewing the L6590ED datasheet, L6590ED pinout, L6590ED application, or L6590ED equivalent, key selection criteria include its integrated 700 V MOSFET with 13 Ω R_DS(on), brownout protection (SMD-only), thermal shutdown with hysteresis, and dual-mode oscillator (65/22 kHz) for light-load efficiency optimization in wall plug adapters and auxiliary supplies.

Technical Context

The L6590ED implements voltage-mode PWM control using an internal error amplifier with 70 dB DC gain and 1 MHz unity-gain bandwidth, referenced to a precision 2.5 V ±2% bandgap. Its oscillator operates at 65 kHz (±10%) under normal load and switches to 22 kHz during light-load standby, triggered by peak primary current thresholds (80 mA / 190 mA).

Protection architecture includes latched overvoltage shutdown (16.5 V V_CC threshold), cycle-by-cycle current limiting (625 mA typ.), brownout detection via BOK pin (2.5 V threshold with 50 µA hysteresis current), and thermal shutdown at 150 °C with 40 °C hysteresis - all implemented in BCD OFF-LINE process technology.

Key Specifications

Pinout & Package

The L6590ED is housed in a 16-pin SOIC Wide (SO16W) package with exposed thermal pad pins (9–16) internally connected to PGND for enhanced heat dissipation. Ground pins are segregated into SGND (pin 5) for signal return and PGND (pins 9–16) for power MOSFET source connection, enabling PCB copper-area heatsinking.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar offline flyback controller applications.

Compared with ICE2A265 and UCC28600, the L6590ED uniquely combines 700 V integration, brownout detection, and automatic 65/22 kHz frequency shifting - making it optimal for cost-sensitive, safety-compliant <15 W adapters requiring minimal external components and robust undervoltage handling.

Availability

L6590ED is available at Aetrix Electronics and suitable for wall plug adapters, monitor auxiliary supplies, desktop PC standby rails, and laser printer logic power requiring stable component supply across industrial and consumer production programs.

Supply support for L6590ED 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 specializing in power management, analog, and microcontroller solutions for industrial, automotive, and consumer markets.

The L6590ED belongs to ST's legacy offline AC-DC controller family, engineered specifically for cost-optimized, integrated flyback converters targeting sub-15 W auxiliary and adapter applications with stringent safety and efficiency requirements.

FAQ

What is the maximum continuous output power achievable with the L6590ED?

The L6590ED is rated for up to 15 W output power in flyback topology with proper heatsinking (≥3 cm² 2 oz copper). At full load, thermal performance depends on R_thj-pins = 20 °C/W and ambient temperature ≤50 °C. Derating is required above 50 °C ambient or with reduced PCB copper area, as confirmed by Figure 12 and thermal data on page 3.

Does the L6590ED support primary-side regulation without an optocoupler?

Yes - the L6590ED supports primary-side regulation using its V_FB pin and internal 2.5 V reference, as demonstrated in Figure 24. The error amplifier compares reflected auxiliary winding voltage to the reference, enabling regulation without optocoupler or secondary-side TL431, though accuracy is lower than secondary feedback.

How does the brownout protection function differ between L6590N and L6590ED?

Brownout protection is exclusive to the SO16W package (L6590ED); the MINIDIP L6590N lacks the BOK pin and associated comparator. In L6590ED, brownout is implemented as a non-latched shutdown triggered when BOK pin voltage falls below 2.5 V, with current-mode hysteresis enabling independent ON/OFF threshold setting via external resistor divider.

Can the L6590ED be used in boost or forward converter topologies?

Yes - the L6590ED's source-grounded MOSFET allows use in boost and forward topologies, as stated in the Description section. For boost, connect DRAIN to input, inductor to SW node, and diode to output; for forward, add reset winding and synchronous rectification control. Layout must maintain creepage/clearance for 700 V drain node per IEC 60950.