FY1005S Signal Generator SL6SD U@ IC Identification – SL6106SE Synchronous Buck Regulator

User question

What is the U@ IC marked SL6SD in the Signal generator FY1005S ?

Artificial Intelligence Response

Direct answer

• Short answer: “SL6SD” is a top‑mark, not a full part number. On FY1005S boards it most commonly denotes a small power‑management IC in a 5‑pin SOT‑23 package located beside an inductor and the 5 V input path—i.e., a synchronous buck regulator of the SL6106SE class used to generate a local low‑voltage rail (typically 3.3 V). If your “U@” device is 5‑pin SOT‑23 next to an inductor and output capacitors, treat it as a DC‑DC step‑down regulator. If the package, location, or surrounding parts differ, see the identification flow below.
• Key points:
  • “U” reference designators are for ICs; diodes/rectifiers are normally “D”. A part marked “U@ … SL6SD” is unlikely to be a rectifier unless the board’s silkscreen is wrong.
  • FY10xxS modules are 5 V powered, DDS‑based, and commonly derive 3.3 V and other rails locally; a tiny buck IC near an inductor is expected in that location. (uniqkart.in)
  • Several BOM variants exist in FY10xxS‑family products; vendor top‑marks are inconsistent, so positive ID requires checking package, pinout, and where it sits in the circuit. Generic SMD code tables warn that top‑marks are ambiguous and context is essential. (manualsfile.com)

Detailed problem analysis

• Why the confusion:
  • SMD top‑marks like “SL6SD” are short internal codes that vary by foundry, lot, and package. They rarely map 1:1 to a single public part number, and the same mark can represent different functions across vendors. This is why internet lookups return contradictory hits. (pic-control.com)
  • The FY1005S is part of a low‑cost DDS generator family; different suppliers ship board revisions with substituted regulators, EEPROMs and op‑amps while keeping the same model number and outward appearance. Retail listings confirm the shared FY10xxS architecture but do not pin down exact IC markings. (uniqkart.in)
• Most technically consistent interpretation:
  • If the component marked “U@ … SL6SD” is a 5‑pin SOT‑23 sited next to a 2–4.7 µH inductor, Schottky‑looking diode pads are absent, and there are 22–47 µF ceramic capacitors to ground, it matches the textbook layout of a tiny synchronous buck (no external Schottky) such as SLKOR’s SL6106SE (2.7–5.5 V in, 1.5 MHz, up to 1.5 A). That device family is ubiquitous on Chinese DDS boards to generate 3.3 V rails from 5 V. Pin functions you should see by tracing:
  • VIN to 5 V input filtering, SW to inductor, GND to ground plane, FB to a resistor divider from the regulated node, EN to logic or VIN via a resistor. (slkoric.com)
• Alternative interpretations you may find online and how to vet them:
  • “It’s a Schottky rectifier”: Unlikely if the silkscreen is U@ and the package has 5 or 6 pins; rectifiers are 2‑lead (SOD/SMA/SMB) or 4‑lead bridges and use “D” or “BR” designators. If yours is truly a 2‑lead SMD part tied from 5 V to ground or part of an input clamp, then it is a diode—but the designator should reflect that. Treat this claim skeptically unless your part is two‑terminal and the silk really says D@.
  • “It’s the configuration EEPROM”: Possible only if the device is an 8‑pin SOIC/TSSOP near the MCU/FPGA and crystal, with two pins routed via 4.7–10 kΩ pull‑ups to a 3.3 V rail (I²C 24Cxx) or four pins to SPI (CS/SCK/MOSI/MISO). Those parts are indeed used for calibration/user settings on FY10xxS units, but they are not placed in the power corner nor next to an inductor.
• Why a buck here makes sense electrically:
  • The FY1005S is powered from 5 V but needs a clean 3.3 V rail (logic/DDS/MCU). Small synchronous bucks like SL6106SE reduce heat and ripple vs. AMS1117‑style LDOs at the same current, so board spins often replace LDOs with 1.2–1.5 MHz bucks in SOT‑23‑5. (slkoric.com)

Current information and trends

• Low‑cost DDS modules frequently rotate BOMs and top‑marks. The same model can carry different regulators (e.g., SL6106SE/JW5211/other 1–1.5 MHz SOT‑23 buck devices) depending on supply, which is why a single marking database rarely resolves the code. (slkoric.com)
• Product listings for FY1005S consistently show a 5 V module with DDS/FPGA control and a 60 MHz counter, aligning with the need for a local logic rail regulator near the power input. (uniqkart.in)

Supporting explanations and details

• Quick identification flow (no schematic required): 1) Count pins and note package.
  • 5 pins (SOT‑23‑5) + nearby inductor ⇒ buck regulator very likely.
  • 8 pins (SOIC/TSSOP) + routes to MCU pins + pull‑ups ⇒ serial EEPROM.
  • 2 pins (SMA/SOD‑123) + series or shunt to 5 V rail ⇒ diode/TVS. 2) Trace critical nets with a DMM:
  • One pin to 5 V input via bead/resistor = VIN; one to ground plane = GND; one to inductor pad = SW; one to resistor divider = FB; one to VIN or MCU = EN. 3) Power‑on measurements:
  • Expect ≈3.3 V on the regulated node; SW pin shows a ~1.5 MHz switching waveform at light load on a scope for many compact bucks. (slkoric.com)
• Typical buck pin map you should observe (SOT‑23‑5):
  • 1: EN (enable), 2: GND, 3: SW (to inductor), 4: FB (to divider), 5: VIN (to 5 V input). Variants shuffle EN/FB, but SW→inductor and VIN/GND are unmistakable. (slkoric.com)

Ethical and legal aspects

• If you later identify an 8‑pin EEPROM, read/clone it only for repair of your own unit; calibration data may be vendor IP. Observe ESD and warranty implications when reworking tiny packages.

Practical guidelines

• To positively confirm yours:
  • Provide a clear photo of both sides around the “U@ … SL6SD” device.
  • Note the pin count and the nearest large passives (inductor value printed? diode footprint present?).
  • With 5 V applied, measure the voltage on each pin versus ground and report:
  • Presence of a switching node (sawtooth/rectangular, ~0.5–2 MHz) confirms a buck.
  • A steady 3.3 V node feeding logic confirms its output.
  • If it is a buck and failed, SL6106SE‑class, JW5211‑class, or similar 1–1.5 MHz SOT‑23‑5 synchronous bucks are practical replacements; match pinout and compensate the FB divider to the original output voltage. (slkoric.com)
• If instead it is an EEPROM (8‑pin), back up contents with a clip/programmer before replacement to preserve calibration and settings.

Possible disclaimers or additional notes

• Some online posts claim “SL6SD” is a Schottky rectifier; that conflicts with a U@ reference designator and with the observed 5‑pin regulator footprints used on these boards. Without a photo/pin count, we cannot fully rule it out if your silkscreen is different, but it is the less likely case on FY1005S.
• FY‑series documentation is vendor‑level, not per‑revision; expect small layout/BOM deviations across batches. (uniqkart.in)

Suggestions for further research

• Share macro photos and we’ll map pins and give you a drop‑in replacement recommendation.
• Useful resources when decoding top‑marks:
  • Manufacturer page for SL6106SE (feature set, pin functions). (slkoric.com)
  • SMD code databases and cautions about ambiguity. (pic-control.com)
  • FY‑series user manuals and retailer listings for architectural context. (manualsfile.com)

Brief summary

• “SL6SD” is a top‑mark used on at least one small 5‑pin buck regulator commonly fitted on FY1005S boards to derive 3.3 V from 5 V. If your “U@” device is a 5‑pin SOT‑23 sitting beside an inductor, treat it as that regulator (SL6106SE‑class). If it’s an 8‑pin device near the MCU with pull‑ups, it’s likely the configuration EEPROM. A two‑pin part near the input would be a diode—but it should then be marked “D”, not “U”. A photo/pin count will let us confirm definitively and name a pin‑compatible replacement. (slkoric.com)

If you can post a clear photo showing the part, its package and the inductor/nearby passives, I’ll pin down the exact function and a compatible substitute.

Disclaimer: The responses provided by artificial intelligence (language model) may be inaccurate and misleading. Elektroda is not responsible for the accuracy, reliability, or completeness of the presented information. All responses should be verified by the user.