Monolithic Power Systems Inc. MP26085DJ-LF-P

Overview

MP26085DJ-LF-P from Monolithic Power Systems is a precision CC/CV controller IC for secondary-side feedback in isolated flyback and forward converters, integrating a 1.223V ±1% voltage reference, dual op-amps with ORED output and 1MHz bandwidth, and an externally controllable current source (1.25mA typ). It enables accurate battery charging and LED driver regulation via optocoupler-coupled feedback to primary-side PWM controllers.

For engineers reviewing the MP26085DJ-LF-P datasheet, MP26085DJ-LF-P pinout, MP26085DJ-LF-P application, or MP26085DJ-LF-P equivalent, this device supports design of compact, high-accuracy constant-current/constant-voltage power supplies for portable chargers, USB PD adapters, and analog/digital dimmable LED drivers - with explicit support for trickle charge offset via ICON pin control.

Technical Context

The MP26085 operates as a dual-loop error amplifier: its CV loop compares VFB against the 1.223V internal reference using one op-amp, while its CC loop compares IFB against IREF (set by R3+R4=44kΩ divider) using the second op-amp; both outputs are ORED at COMP to drive an optocoupler LED. The integrated current source (enabled when ICON < 0.6V) injects offset current into the IREF node to dynamically adjust current limit without changing RSEN.

Its TSOT23-8 package supports high-density layout in space-constrained AC/DC adapters; supply input range (7–20V) accommodates auxiliary winding voltages across universal-input designs, and thermal resistance (θJA = 220°C/W) defines power dissipation limits under continuous operation up to +85°C ambient.

Key Specifications

Pinout & Package

MP26085DJ-LF-P is housed in an 8-pin TSOT23 package (JEDEC MO-193BA), with 0.65mm pitch, 2.9mm × 1.6mm footprint, and exposed pad for thermal relief. Pin 1 is bottom-left when top marking "AAX" is read left-to-right.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar CC/CV controller applications.

Compared with UCC3803DR and TL431AIDBZR, MP26085DJ-LF-P integrates dual op-amps, a programmable current source, and a precision 1.223V reference in one TSOT23-8 package-reducing component count by ≥6, enabling dynamic current limit adjustment, and supporting advanced charging profiles without external logic.

Availability

MP26085DJ-LF-P is available at Aetrix Electronics and suitable for USB-C PD adapters, lithium-ion battery chargers, and dimmable LED drivers requiring stable component supply, RoHS-compliant packaging, and long-term lifecycle continuity.

Supply support for MP26085DJ-LF-P 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

Monolithic Power Systems (MPS) is a fabless semiconductor company specializing in high-performance analog and power ICs, with design centers in the US, China, and Taiwan, and global distribution through authorized partners.

The MP26085 belongs to MPS's secondary-side controller product line, engineered specifically for compact, high-accuracy isolated power supplies targeting consumer, industrial, and lighting applications where space, efficiency, and regulation precision are critical.

FAQ

What is the function of the ICON pin on MP26085DJ-LF-P?

The ICON pin enables or disables the internal current source: pulling ICON below 0.6V activates the 1.25mA source, which offsets the IREF node to reduce regulated current; connecting ICON to >2V disables it. This allows dynamic current limit adjustment-e.g., transitioning from fast charge to trickle mode-without modifying RSEN or the feedback divider.

Can MP26085DJ-LF-P be used with primary-side controllers other than MPS devices?

Yes. MP26085DJ-LF-P interfaces universally with any primary-side PWM controller via optocoupler feedback. Its COMP pin sinks up to 15mA, compatible with standard PC817-series optocouplers used with controllers from ON Semiconductor (NCP12xx), Infineon (ICE2QSxx), or TI (UCC287xx), provided the primary-side controller accepts opto-coupled error signals.

How is the constant output voltage set using MP26085DJ-LF-P?

Output voltage is set by a resistor divider from output to GND, connected to VFB. With VREF = 1.223V, select R2 (low-side) = 10kΩ, then calculate R1 (high-side) as R1 = R2 × (VO − 1.223)/1.223. For example, for VO = 12V: R1 = 10kΩ × (12 − 1.223)/1.223 ≈ 88.1kΩ. Standard 1% E96 values (e.g., 88.7kΩ) yield <0.5% error.

What is the maximum allowable power dissipation for MP26085DJ-LF-P in TSOT23-8?

At TA = 25°C, maximum continuous power dissipation is 0.45W (from θJA = 220°C/W and TJ(MAX) = +125°C). At +85°C ambient, usable power drops to (125 − 85)/220 = 0.182W. Derating is required above 25°C; thermal shutdown activates if junction temperature exceeds +125°C, protecting the device during overload or poor heatsinking.

Does MP26085DJ-LF-P support both analog and digital dimming in LED applications?

Yes. In LED drivers, the IREF pin accepts either an analog dimming voltage (via resistor network) or a digitally switched reference (using external transistor like Q4 in Figure 4). The internal current source and dual op-amps allow independent regulation of LED current while maintaining stable auxiliary rail voltage-supporting smooth 0–10V analog dimming and clean PWM dimming up to 5kHz.

What is the recommended bypass capacitor for the IN pin?

A minimum 4.7μF X5R/X7R ceramic capacitor rated ≥16V must be placed between IN and GND, located within 2mm of the MP26085DJ-LF-P pins. This stabilizes the internal bias circuitry and suppresses high-frequency noise from the auxiliary winding; adding a parallel 100nF capacitor improves HF decoupling for reliable operation at switching frequencies >200kHz.

How does the ORED COMP output improve system reliability?

The ORED COMP output combines CV and CC loop outputs into a single node: whichever loop demands lower output voltage dominates, ensuring automatic transition between modes without external logic. This prevents overvoltage during CC mode or overcurrent during CV mode-eliminating latch-up risk and simplifying fault response in battery and LED applications.