Up0104s Datasheet (Essential ✔)

In the world of power supply design, few components are as critical—or as widely misunderstood—as the PWM (Pulse Width Modulation) controller. Among the myriad of options available to engineers and repair technicians, the UP0104S stands out as a highly specialized, dual-output controller. While not a household name, this IC is a workhorse found on numerous motherboards, graphics cards, and embedded systems, particularly those manufactured in the late 2000s and early 2010s.

If you are searching for the UP0104S datasheet, you are likely facing one of three scenarios: designing a low-voltage power rail, troubleshooting a dead motherboard with missing VCORE, or attempting a repair on a GPU that refuses to power up. This article serves as an exhaustive resource—synthesizing the critical electrical characteristics, pinout, application circuits, and troubleshooting tips found in the official technical documentation.

The UP0104S is a synchronous buck (step-down) PWM controller designed to convert a higher input voltage (e.g., 12V) into a lower, precisely regulated output voltage (e.g., 1.2V–5V) with high efficiency. It is frequently found in DDR memory power supplies, chipset/VCCIO rails, and general point-of-load (POL) regulation on PC motherboards, LCD TVs, and embedded systems.

VIN (12V) → VCC (pin1)
EN1/EN2 → logic high or resistor divider from VCC

Channel 1:
UGATE1 (pin9) → high-side MOSFET gate
PHASE1 (pin7) → MOSFET source & inductor
LGATE1 (pin5) → low-side MOSFET gate
BOOT1 (pin8) → 0.1µF cap to PHASE1
FB1 (pin3) → resistor divider from VOUT1
COMP1 (pin4) → RC series to FB1 Up0104s Datasheet


Channel 2 similar using pins 10–14.

The UP0104S is a robust, simple synchronous buck controller for moderate to high current, but its exact specifications vary by manufacturer and suffix (e.g., UP0104S vs UP0104P). Always refer to the official datasheet for absolute maximum ratings and exact pinout. In the world of power supply design, few

Would you like a schematic example or help calculating resistor values for a specific output voltage?

  • Compensation: An RC network from COMP to GND (Pin 14 to Pin 6) stabilizes the voltage control loop. The datasheet provides calculations for Type II compensation.
  • Soft-Start: A capacitor on SS (Pin 3) determines the inrush current. Value range: 0.01µF to 1µF.

    • Example Dual Output Design:

    How does the UP0104S stack up against alternatives? The datasheet reveals its niche. The UP0104S is a synchronous buck (step-down) PWM

    | IC | Channels | Max VIN | Special Feature | Compatibility | | :--- | :--- | :--- | :--- | :--- | | UP0104S | 2 | 12V | Dual independent, simple enable | Native | | RT8101A | 1 | 12V | Single, higher gate drive | Not a direct drop-in | | APW7120 | 1 | 12V | Single with OVP | Different pinout | | ISL6227 | 2 | 24V | More advanced sequencing | Larger package |

    The UP0104S is ideal when you need two independent rails (e.g., 1.2V and 2.5V) from a single 12V supply without the complexity of I2C or sequencing.

    To ensure stability and prevent oscillation, the uP0104 requires capacitors on both the input and output.

    If UP0104S is not available, consider:

    Always compare gate drive capability, voltage range, and frequency.