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What is an LED driver?

  Topdiode Group & UF Capacitors provide components solution for below: Led control circuit; SMPS for LED TV, SMPS circuit; ESL.

  Basic knowledge of drive

  What is an LED driver?

  The LED driver changes the power supply to a specific voltage and current to drive the LED voltage converter. Generally speaking, the input of the LED driver includes high-voltage power frequency AC (ie, mains), low-voltage DC, high-voltage DC, and low-voltage and high-frequency AC (such as the output of electronic equipment). transformer). The output of the LED driving power supply is mostly a constant current source, and the voltage can be changed as the forward voltage drop of the LED changes. The core components of LED power supply include switching controller, inductor, switching element (MOSFET), feedback resistor, input filter, output filter, etc. According to the requirements of different occasions, there must be input overvoltage protection circuit, input undervoltage protection circuit, LED open circuit protection,

  Electronic Shelf Label (ESL) Circuit, PCB Assembling

  Low loss rectifier circuit 

  Multi-channel LED control 



  Electronic Shelf Label circuit use 100uF 6.3V A case tantalum capacitors, in the past, only AVX Capacitors can provide 100uF in A case. We Topdiode UF Capacitors, #Chinacapacitorsfactory#chinacapacitorssupplier have mature technology, and we can supply 100uF in A case.

  6.3V 100UF 107J TAJA107K006RNJ A case ±10% 1206 SMD Tantalum Capacitors

  SMD tantalum capacitor 100UF 3216 AVX TAJA107K006RNJ 6.3V type A

  TAJA685K016RNJ 16V 6.8UF 685C A case ±10% 1206 SMD Tantalum Capacitors

  6V 47UF A case 476C ±10% 1206 SMD Tantalum Capacitors 3.2mm×1.6mm

  16V 10UF B case 106C TAJB106K016RNJ 1210 ±10% SMD Tantalum Capacitors

  16V 4.7UF 475C TAJA475K016RNJ A case ±10% 1206 SMD Tantalum Capacitors

How to correctly determine the positive and negative poles of chip tantalum capacitors?

How to correctly determine the positive and negative poles of chip tantalum capacitors?

           One end of the chip tantalum capacitor is marked with a horizontal line, which is the positive electrode of the chip tantalum capacitor, and the other end is the negative electrode. The long end of the lead tantalum capacitor is the positive electrode, and the short end is the negative electrode.

   SMD tantalum capacitors are polar capacitors. The positive and negative poles cannot be reversed. In case of reverse connection, the tantalum capacitor will not work or fail.
   The positive and negative poles of SMD tantalum capacitors are distinguished and measured. The black block with the mark on the tantalum capacitor is the negative pole. There are two semicircles on the capacitor position on the PCB, and the pin corresponding to the colored semicircle is the negative pole. The length of the pins is also used to distinguish the positive and negative poles as positive and short pins as negative.
   When we don’t know the positive and negative poles of SMD tantalum capacitors, we can use a multimeter to measure them. The medium between the two poles of the capacitor is not an absolute insulator, and its resistance is not infinite, but a finite value, generally above 1000 megohms. The resistance between the two poles of the capacitor is called insulation resistance or leakage resistance, and only electrolytic capacitors When the positive pole of the electrolytic capacitor is connected to the positive power supply (the black test lead when the electricity is blocked), and the negative terminal is connected to the negative power supply (the red test lead when the electricity is blocked), the leakage current of the electrolytic capacitor is small (the leakage resistance is large).

What are TVS Diodes?

  What are TVS Diodes?

  By Kelvin Tan

  TVS Diodes are electronic components designed to protect sensitive electronics from high-voltage transients. They can respond to overvoltage events faster than most other types of circuit protection devices, and are offered in a variety of surface mount and through-hole circuit board mounting formats.

  They function by limiting voltage to a certain level (referred to as a "clamping" device) with p-n junctions that have a larger cross-sectional area than those of a normal diode, allowing them to conduct large currents to ground without sustaining damage.

  TVS Diodes are generally used to protect against electrical overstress such as those induced by lightning strikes, inductive load switching, and electro-static discharge (ESD) associated with transmission on data lines and electronic circuits.

  topdiode TVS Diodes can fit a wide range of circuit protection applications but were primarily designed to protect I/O interfaces in telecommunication and industrial equipment, computers and consumer electronics.

  topdiode TVS Diode characteristics include:

  Low incremental surge resistance

  Unidirectional and Bidirectional polarities available

  Reverse standoff voltages range from 5 to 512V

  RoHS compliant–Matte Tin Pb-free plated

  Surface-mount power ratings from 400W to 5,000W

  Axial lead power ratings from 400W to 30,000W (30kW)

  High current protection available for 6kA and 10kA

  TVS Diode Glossary

  Clamping Device

  TVS is a clamping device that limits voltage spikes by low impedance avalanche breakdown of a rugged silicon PN junction. It is used to protect sensitive components from electrical overstress generated by induced lightning, inductive load switching and electrostatic discharge.

  Operating Temperature Range

  The minimum and maximum ambient operating temperature of the circuit in which a device will be applied. Operating temperature does not allow for the effects of adjacent components, this is a parameter the designer must take into consideration.


  The property of a circuit element that permits it to store an electrical charge. In circuit protection, the off-state capacitance is typically measured at 1 MHz with a 2V bias applied.

  Reverse Standoff Voltage (VR)

  In the case of a uni-directional TVS diode, this is the maximum peak voltage that may be applied in the 'blocking direction' with no significant current flow. In the case of a bi-directional transient, it applies in either direction. It is the same definition as Maximum Off-state Voltage and Maximum Working Voltage.

  Breakdown Voltage (VBR)

  Breakdown voltage measured at a specified DC test current, typically 1mA. Usually a minimum and maximum is specified.

  Peak Pulse Current (IPP)

  Maximum pulse current which can be applied repetitively. Usually a 10x1000μs double exponential waveform, but can also be 8x20μs, if stated.

  Maximum Clamping Voltage (VC or VCI)

  Maximum voltage which can be measured across the protector when subjected to the Maximum Peak Pulse Current.

  Peak Pulse Power (PPP)

  Expressed in Watts or Kilowatts, for a 1ms exponential transient  it is IPP multiplied by VCL.

  P4KE6.8-P4KE440CA Axial Leaded 400W TVS Diode P4KE series

  P6KE6.8-P6KE440CA Axial Leaded 600W TVS Diodes P6KE series

  SMAJ5.0--SMAJ440CA Surface Mount TVS -Topdiode

  SMBJ5.0--SMBJ440CASurface Mount TVS -Topdiode

  SMCJ5.0-SMCJ440CA 1500W Suface Mount TVS Diode Topdiode

  TVS DIODE SD03, SD05, SD12-Topdiode


  SMDJ5.0--SMDJ170CA-Surface Mount TVS -Topdiode

  ESD3Z_SERIES SOD-323-Topdiode


  TVS Diodes P6SMB6.8-440ACA Topdiode

  TVS Diodes-P4SMA6.8-440ACA



  By Kelvin Tan
  What is RoHS? What is RoHS 2.0? What is RoHS 3.0?

  Directive 2011/65/EU was published in 2011 by the EU, which is known as RoHS-Recast or RoHS 2. RoHS 2 includes a CE-marking directive, with RoHS compliance now being required for CE marking of products. RoHS 2 also added Categories 8 and 9, and has additional compliance recordkeeping requirements.
  Directive 2015/863 is known as RoHS 3. RoHS 3 adds four additional restricted substances (phthalates) to the list of six.
  As now China's test lab does not have RoHS 3.0 test standard. So Topdiode and UF Capacitors only declare our products are RoHS 2.0 Compliant. We will update our certification according to latest regulations.
  RoHS Compliant for 2022
  Any business that sells applicable electrical or electronic products, equipment, sub-assemblies, cables, components, or spare parts directly to RoHS-directed countries, or sells to resellers, distributors or integrators that in turn sell products to these countries, is impacted if they utilize any of the restricted 10 substances.
  With the rapid spread of digitization, the world's production of electrical and electronic devices is exploding. Besides mobile devices, think about the coming wave of IoT, smart home assistants, robots, drones, 3D printers, and home medical devices to all corners of the planet...they are all regulated under RoHS.
  EU RoHS specifies maximum levels for the following 10 restricted substances. The first six applied to the original RoHS while the last four were added under RoHS 3, which took effect July 22, 2019.
  Cadmium (Cd): < 100 ppm
  Lead (Pb): < 1000 ppm
  Mercury (Hg): < 1000 ppm
  Hexavalent Chromium: (Cr VI) < 1000 ppm
  Polybrominated Biphenyls (PBB): < 1000 ppm
  Polybrominated Diphenyl Ethers (PBDE): < 1000 ppm
  Bis(2-Ethylhexyl) phthalate (DEHP): < 1000 ppm
  Benzyl butyl phthalate (BBP): < 1000 ppm
  Dibutyl phthalate (DBP): < 1000 ppm
  Diisobutyl phthalate (DIBP): < 1000 ppm
  About Lead-Free and RoHS
  In practice, RoHS-compliant is often equated with “lead-free”. However, this is a widespread mistake. The RoHS directive 2002/95/EC aims to minimize the use of hazardous substances (including, among others, lead), but it does not completely exclude a small percentage. One of the great obstacles in implementing the directive was the switchover to lead-free solder, because the limit values (0.1 per cent by weight of the inseparable components) do not admit a lead solder. This is probably the most important reason for the mix-up/equating that comes up again and again.
  Due to environmental concerns, the need for lead-free solutions in electronic components and systems is receiving increasing attention within the semiconductor and electronics industries.
  In a word, Lead Free and Pb Free is the same thing. Due to worldwide environmental restricted chemical and material (RCM) concerns, it was determined lead (Pb) as one of the major substances of concerns. Lead-free devices in electronic components and systems continues to receive significant attention within the semiconductor and electronics industry as a whole.
  Lead Free and Pb Free mean "No PB Process". PB Free and Lead-Free electronics components are definitely RoHS Compliant. But RoHS Compliant did not mean Pb Free of Lead Free.
  RoHS Compliant means lead <1000 PPM, and also accept exemption sometimes.
  Ps: Green products mean stricter: Lead (Pb): < 90 ppm
  Topdiode & UF Capacitors’ all components are RoHS Compliant. But not all our electronic components are PB Free or Lead-Free. If you require Lead-Free, pls check case by case.

Topdiode DB107S

Topdiode DB107S, Bridge Rectifier, 1A 1000V, 4-Pin DBS

  Manufacturer Topdiode part number: DB107S
  Gross weight: 0.378 g
  Bridge rectifier: single-phase; 1000V; If: 1A; SMT Bridge Rectifier,
  DB101S THRU DB107S  Single Phase, Glass Passivated Silicon Bridge Rectifier
  RoHS Reach compliant
  Topdiode L/T: 3-4 wks
  #Rectifler#Single-phasebridgetypefullycontrolledrectifiercircuit#Bridgerectifier#Theroleofthe rectifier#Electronic#rectifier##diode#shortage#chinasupply#maker#electroniccomponents#discrete#semiconductors#transistors#mosfet#diodes#chinabridgefactory#

CL23 Mini box 5mm pitch metalized polyester capacitors.

UF Capacitors are ISO 9001: 2008 certified manufacturer.  We produce ceramic capacitors, radial tantalum capacitors and kinds of MKT MKP film capacitors.
UF Capacitors Offer:
CL23 Mini box 5mm pitch metalized polyester capacitors.
Replacement of Kemet: MKT R82 (R85), Epcos B32529
Lead time: 2-4 weeks

1000pF 100V +/-5% P: 5mm Bulk RoHS       US$0.016/pc

2200pF 400V +/-5% P: 5mm Bulk RoHS       US$0.020/pc

0.68uF 100V +/-5% P: 5mm Bulk RoHS       US$0.065/pc



Vishay Capacitor Mono-Kap 199D 561R 564R

Below I listed you Vishay’s capacitors, we UF Capacitors have replacement offer to Vishay’s cap. We do NOT sell Vishay’s capacitors, and we are manufacturer producing capacitors ourselves in China. Our high quality capacitors can replace Vishay’s below series: Mono-Kap, 199D, A series Axial MLCC, 561R &564R high voltage disc cap.

Do you buy or use Vishay’s capacitors? You could please send me the description or part number, I will cross and quote you.  For many common capacitors, we keep wide stock!

Vishay  K Series Mono-Kap:   Dipped Radial Multilayer Ceramic Capacitors for 50 - 100 Vdc
UF Capacitors’ equivalence offer: CT4 radial multilayer ceramic capacitor

VISHAY  199D   Solid-Electrolyte TANTALEX® Capacitors, Resin-Coated, Radial-Lead
UF Capacitors’ equivalence offer: CA42 radial tantalum capacitors

Vishay  A Series  Axial Leaded Multilayer Ceramic Capacitors for General Purpose Class 1, Class 2 and Class 3, 50 VDC, 100 VDC, 200 VDC, 500 VDC
UF Capacitors’ equivalence offer:  CT42 axial lead, multilayer ceramic capacitor

Vishay   561R Series  Lower Voltage Ceramic DC Disc Capacitors 1000 VDC Precision Capacitors
564R and 565R Series  Lower Voltage Ceramic Singlelayer DC Disc Capacitors 2 kVDC to 7.5 kVDC
UF Capacitors' equivalence offer: CT81 high voltage disc ceramic capacitors, 500V to 10KV

High capacitance chip MLCC

High capacitance chip MLCC, Common items with regular stock pls contact sales@topdiode.com  www.topdiode.com

1206, 10nF, +/-10%, 1KV, X7R, T&R, RoHS
1210, 22uF, +/-20%, 16V, X7R, T&R, RoHS
1206, 100uF, +/-20%, 10V, X5R, T&R, RoHS
0603, 10uF, +/-20%, 10V, X5R, T&R, RoHS 0805,
4.7uF, +/-10%, 50V, X5R, T&R, RoHS
0805, 22uF, +/-20%, 16V, X5R, T&R, RoHS
1206, 100uF, +/-20%, 10V, X5R, T&R, RoHS

Ms. Win Tang
Sales Manager
Skype: topdiode
Tel.: +86-(0)769 8252 3211
Topdiode Group & UF Capacitors Factory
ISO 9001: 2008, Military Qualification: GJB90018:2009 for tantalum cap RoHS, Reach, Halogen free, Metal Conflict Free Manufacturer for: Capacitors, MOVs, Diodes, Bridge, Transistors

CAP ALUM 100uF 16V SMD Price Offer

Dear ,

Nice day! Could you please check our SMD Alum Capacitor Price Offer?

We offer very strong prices for SMD electrolytic capacitors: 85’C 105’C Standard, long life series, low impedance SMD electrolytic capacitors.

Our SMD ELCO Capacitors meet RoHS, Reach, Halogen free, please visit our PDF SPEC and certifications on website.

Our TCS, TCK series can replace Epcos B41112, B41123, Samwha SC/RC Series, Nichicon UWX, UWT series. Pls check our download page, you will find our company profile, catalogue, and cross guide for capacitors, MOVs.  Cross guide will be very helpful for your sales!

Pls check below our offer, welcome to send your inquiry for capacitors and MOVs. Thank you.

Panasonic EEE-HA1V220WR Our Offer: 22uF 35V +/-20% 5x 5.4mm 1000h 105’C T&R RoHS US$0.0148/pc
Panasonic EEE-HA1C101WP Our Offer: 100uF 16V +/-20% 6.3x5.4mm 1000h 105’CT&R RoHSUS$0.0192/pc
Panasonic EEE-HA1H470XP Our Offer: 47uF 50V +/-20% 6.3x7.7mm 2000h 105’C T&R RoHS  US$0.023/pc
Panasonic EEE-HA1H470UP Our Offer: 47uF 50V +/-20% 8x10.5mm 2000h 105’C T&R RoHS US$0.0465/pc

Remark: for last two items, Panasonic offer 1000hours only. For standard series, our offer is 2000hours

Ms. Win Tang
Sales Manager
Skype: topdiode
Tel.: +86-(0)769 8252 3211
Topdiode Group & UF Capacitors Factory

ISO 9001: 2008, Military Qualification: GJB90018:2009 for tantalum cap
RoHS, Reach, Halogen free, Metal Conflict Free
Manufacturer for: Capacitors, MOVs, Diodes, Bridge, Transistors

MPX Series Audio Capacitors: Premium Metallized Polypropylene Film Capacitors, Axial Lead

MPX Series Audio Capacitors from UF Capacitors are premium, high precision metallized polypropylene film, axial lead, bipolar capacitors especially designed for audio applications. They exhibit very low ESR and inductance and handle high audio current pulses extremely well. Other features are very low dielectric absorption and dissipation factors.

Quick transient designHigh Precise Capacitance +/ -3% (I),+/ -5% (J)
Wide Capacitance range 0.047~100uF
Rated voltage 250V400V630V.DC
Very Low Dielectric Absorption Factor
Very Low ESR
Very Low Dissipation Factor
Very Low Inductance
Welded and Hand Soldered Leads
Excellent Handling of High Current Audio Pulses
RoHS Compliant