Sourcing Components: Delays!

I received the package of samples from ON Semiconductor. FedEx Overnight! Much to my dismay they shipped everything BUT the LED drivers. Oh no! Those were the only reason why I sourced samples from ON. Whatever they are creating, I hope it’s quick.

Then I found out from DigiKey that the microcontroller is backordered until February 15th. So much for spending this week getting familiar with it.

Sourcing Power Components

The LED lamp’s electronics can be divided into three sections:

• Control System
  • To accept user input, manipulate input data, send commands to LED drivers.
• LED Driver System
  • To drive the LED at a constant current.
• Power System
  • To provide adequate and stable power to the Control and LED Driver Systems.

ON Semiconductor was chosen to provide most of power circuitry, mainly because they were the only ones to offer a 1.5A LED driver in PDIP form. PDIP can be easily hand soldered, as they are through hole components.

PDIP

SOIC are much harder and TSOP nearly impossible to hand solder. The latter two are known as surface mount technology devices. These types of components are used in large volume production runs in consumer electronics.

SOIC

TSOP

The following parts have been sourced from ON Semiconductor through their samples program. Unfortunately their sample program requires a $11 shipping and handling charge. While it isn’t much, one better load up on samples to make the charge worthwhile. There is a maximum of 25 samples per component. It seems that DigiKey is the fulfillment operator, and the samples were shipped FedEx Overnight.

LED driver 1.5A NCP3065PG
Voltage regulator 5v 1A MC7805ABTG
Voltage regulator 3.3v 800mA MC33269T-3.3G
Voltage regulator 1.2-37v 1.5A LM317BTG
Bipolar junction transistor 2N3904G

DigiKey Delivers

Got home from work and there’s a nice package waiting for me on the table. DigiKey has some of the best packaging material ever! My friend and I used to line our cubes with that stuff back at Foster-Miller. It’s like camo netting, sorta.

Here’s a few pictures:

What the box contained

The light engine is TINY!

Global eBaying for parts

Ordered some ZIF and DIP sockets from eBay yesterday, all the way from Hong Kong. The ZIF connector will be used for the microcontroller development board. The DIP socket will be used to mount the microcontroller onto the lamp veroboard.

ZIF connector

DIP Socket

• ZIF connector
• DIP socket

With a ZIF (zero insertion force) connector, I don’t have to worry about bending, or worse, breaking pins when working with microcontrollers. When removing ICs from a socket, a relatively large amount of force is needed to insert and remove the part. With a ZIF, simply unlock, place the chip on top and lock into place.

DIP sockets come in handy during the soldering. Too much heat can destroy microcontrollers and other ICs. With that being said, simply solder the socket onto the veroboard then insert the device onto the socket.