Components

On the MAX11200EEE+ and the MAX112100EEE+, bit 3 of the command byte is named IMPD but this bit is never described in detail in the datasheet.

The meaning of this bit is Immediate power-down. When you set it to 1, the IC will switch to power-down mode. This is evidenced by the power-down example in Table 8 in the datasheet.

The MAX11200EEE+ and the MAX112100EEE+ operate using SPI Mode 0. Therefore, CPHA=0 & CPOL=0.

For more information, see the datasheet.

Generally, SMD ferrites of a given size are characterized by:

• The RF impedance (typically specified @100 MHz)
  • Low impedance (e.g. 100 Ω @ 100 MHz) do not filter EMI that well, but also distort your data signals less. Use them for high speed signals above 1 MHz
  • High impedance ferrites, e.g. 1kΩ @ 100 MHz, filter EMI really well but will distort any high speed signal. Use them for low speed signals below 1 MHz
• The current rating
  • For data signals, you don’t need any form of high current rating. Generally, I would recommend to require at least 0.1A of current rating to be able to handle soft short circuits
  • For power lines, use whatever power rating is suitable (the specified current + 20% is typically fine)
• The DC resistance. This mostly only matters for power lines.
  • Keep in mind to keep the ferrite cool by choosing the DC resistance so that the

As with most passive parts, LCSC generally has the lowest pricing if you buy a bunch of parts.

Keep in mind the expensive shipping, but since they are often 50 times cheaper (!) than other distributors, it might be worth it even if just ordering a reel of ferrites.

Signal ferrites

This section contains cheap SMD ferrite beads for < 1A current rating.

Low impedance (<= 500Ω):

• LCSC 0603 100Ω 200mA CBG160808U101T @ 0.0019€/[email protected] = 7.60€/reel

High impedance (>= 500Ω):

• LCSC 0805 600Ω 300mA CBG201209U601T @ 0.0026€/[email protected] = 10.40€/reel
• LCSC 0603 1kΩ 400mA FCM1608KF-102T04 @ 0.0027€/[email protected] = 10.80€/reel
• LCSC 0805 1kΩ 800mA CBW201209U102T @ 0.0044€/[email protected] = 17.60€/reel
• DigiKey 0603 1kΩ 400mA 2506031027Y0 @ 0.01264€/[email protected] = 50.56€/reel
• TME 0805 1kΩ 200mA LCCB-102 @ 0.0181€/pc = 72.40€/reel

Power ferrites

This section contains cheap SMD ferrite beads for > 1A current rating.

Low impedance (<= 500Ω):

• LCSC 1206 120Ω 3A CBW321609U122T @ 0.006€/[email protected] = 24. 00€/reel
• LCSC 1206 120Ω 4A CBM321609U121T @ 0.0086€/[email protected] = 34.40€/reel

High impedance (>= 500Ω):

• LCSC 1206 1.2kΩ 1A CBW321609U122T @ 0.0088€/[email protected] = 35.20€/reel
• LCSC 1206 1kΩ 2A CBW321609U102T @ 0.0095€/[email protected] = 38.00€/reel

I generally use the LTV-356T optocoupler (phototransistor output) for general purpose applications. It has a smaller footprint than most DIP-derived SMD optocouplers and a thinner package. Its pin pitch is 2.54mm whereas the center-distance between the pads is 6.5mm. It it rated

It is available:

• from DigiKey @ 0,12€/[email protected]
• from LCSC @ 0,056€/[email protected]

Even cheaper?

The LTV-356T has the advantage of being available from different sources in large quantities. However, you can get a pin-compatible variant LTV-356T-C which is only rated for 35V on the output:

• from LCSC @ 0,0404€/[email protected]

Even smaller?

At LCSC, you can also get the half-width OR-3H7B-TP-Gwith a pin pitch of only 1.27mm for 0,0424€/[email protected]

Typically, 1% thick film resistors are used as general purpose SMD resistors. Most of these are spec’d with a 100ppm/°C temperature coefficient.

From all the “normal” distributors, in my experience LCSC has by far the cheapest resistors – around 3€ per reel (5000pcs) of 0603 resistors. Note, however, that they charge around 35€ of shipping to Germany. So you have to buy a lot of resistors in order to compensate for the expensive shipping. However, you can also order other components on LCSC (they’re usually quite cheap, especially for passives and other standard components).

0603 resistors

• 10Ω 1% 100mW: WR06X10R0FTL @ 0.0006€/pc = 3€/reel
• 75Ω 1% 100mW: FRC0603F75R0TS or RTT0375R0FTP @ 0.0006€/pc = 3€/reel
• 2.2kΩ 1 100mW: FRC0603F2201TS @ 0.0006€/pc = 3€/reel
• 10kΩ 1 100mW: 0603WAF1002T5E  @ 0.0006€/pc = 3€/reel
• 12.1kΩ 1 100mW: FRC0603F1212TS @ 0.0006€/pc = 3€/reel
• 33kΩ 1% 100mW: RTT033302FTP or SC0603F3302F2BNRH @ 0.0006€/pc = 3€/reel
• 68kΩ 1 100mW: FRC0603F6802TS @ 0.0006€/pc = 3€/reel
• 220kΩ 1 100mW: FRC0603F2203TS @ 0.0006€/pc = 3€/reel

You can find 3D models as 3D-PDF for JST XH connectors on the JST website.

However, in order to obtain STEP or IGES models, you have to look on the jst-mfg.com site.

LCSC is typically the cheapest vendor for buying reels. Note, however, that the shipping fee is rather expensive (around 35€ to Germany), so it will only be worth the saving if you order larger quantities of components.

• 10nF 0603 50V: 4000pcs of Yageo CC0603KRX7R9BB103 for 5,20€
• 100nF 0603 50V: 4000pcs of CCTC TCC0603X7R104K500CT for 4,80€

You can find the 3D models on the Taiyo Yuden website.