SMT Bandito Info/Build

[Koala]

going to plod along with digi-key

The right size resistors in thin film are 1/4 of the price

just had a quick look and they have all the IC's and diodes except TLC22262?

If they have 90% of everything then there will only be one delivery charge then get the rest from eBay.

[Koala]

1x 20 RNCP1206FTD20R0CT-ND $.09
1x 100 RNCP1206FTD100RCT-ND $.09
2x 150 RNCP1206FTD150RCT-ND $.09
1x 200 RNCP1206FTD200RCT-ND $.09
6x 1K RNCP1206FTD1K00CT-ND $.09
1x 1.2K RG32P1.2KBCT-ND $.65
2x 2.2K RG32P2.2KBCT-ND $.65
2x 4.7K RG32P4.7KBCT-ND $.65
5x 5.1K RG32P5.1KBCT-ND $.65
8x 10K RNCP1206FTD10K0CT-ND $.09
1x 12K RG32P12.0KBCT-ND $.65
8x 20K RNCP1206FTD20K0CT-ND $.09
1x 27K RG32P27.0KBCT-ND $.65
4x 47K RG32P47.0KBCT-ND $.65
1x 82K P82KBCCT-ND $.79
10x 100K RG32P100KBCT-ND $.65
1x 150K RG32P150KBCT-ND $.65
5x 200K RG32P200KBCT-ND $.65
1x 430K RNCF1206DTE430KCT-ND $.55
1x 470K RG32P470KBCT-ND $.65
2x 620K P620KBCCT-ND $.79
4x 1M MCA1206-1.00M-CFCT-ND $,53
2x 2.7M 311-2.70MFRTR-ND thick film $.003

[Silver Dollar]

Yow some of those are expensive! I just completed a new layout. I fixed a problem with an ungrounded cap
and changed the TX to the Minelab one. I also added a MIC5207 LDO setup for the main 5V and another for
the TX itself (I have these handy).
Here's a picture;
Note with the Minelab you don't need the 1.2K , 12K and 20K!

[Koala]

You have been busy

Done some more reading and thin film may not be suitable for a detector thin film resistors are susceptible to moisture Thick film resistor elements become glasslike after firing, which means they are inherently impervious to moisture

So going for thick film things get much easier 1% ±100ppm/°C in 1206 size which is the same spec as the cheapest thin film are easy and much cheap to find

[Silver Dollar]

I thought the thin ones were more stable as they are on a silicon substrate. As long as they are
1% it doesn't matter to me. You can always coat the finished PCB with conformal coat to protect
it from the elements.

I did a few more tweaks to the new layout today. I added a couple of pads so you can select the
diodes you want for sound. I also added a couple of mods from the attached schematic. One is two
20 meg resistors (oops more values to buy!, those are for the PP mode and helps ground balance
I think. And an option to jump the sensitivity pot to -5v through a resistor. Some used that one the
Golden Saber to get closer to the noise floor. You can still stuff the original resistor and use it per
the original design.

[Silver Dollar]

I'm still unclear on the mistake for the pass transistor on the output of the negative supply.
Chemlec showed a PNP with the emitter to the output then corrected it to a NPN with the
emitter going to the input. I found a picture on the WEB of a capacitance multiplier with
a NPN with Emitter to the output but I'm not sure if this being a negative supply changes
things....



I found the answer! If you have a negative supply it goes this way;

[Koala]

Yep I would go with that the three successful builds on here Firebox Hugo and ashefr10 used a 2N3906 PNP wounder how bernte_one got on

[Koala]

This are 1% thick film

total at the end of each line include muli purchases

RMCF1206FT20R0CT-ND RES 20 OHM 1/4W 1% 1206 £0.04
RMCF1206FT100RCT-ND RES 100 OHM 1/4W 1% 1206 £0.04
RMCF1206FT150RCT-ND RES 150 OHM 1/4W 1% 1206 £0.08
RMCF1206FT200RCT-ND RES 200 OHM 1/4W 1% 1206 £0.04
RMCF1206FT1K00CT-ND RES 1K OHM 1/4W 1% 1206 £0.24
P1.20KFCT-ND RES 1.2K OHM 1/4W 1% 1206 SMD £0.07
311-2.20KFRCT-ND RES 2.20K OHM 1/4W 1% 1206 SMD £0.14
RMCF1206FT4K70CT-ND RES 4.7K OHM 1/4W 1% 1206 £0.08
P5.10KFCT-ND RES 5.1K OHM 1/4W 1% 1206 SMD £0.35
RMCF1206FT10K0CT-ND RES 10K OHM 1/4W 1% 1206 £0.32
RMCF1206FT12K0CT-ND RES 12K OHM 1/4W 1% 1206 £0.04
RMCF1206FT20K0CT-ND RES 20K OHM 1/4W 1% 1206 £0.32
P27.0KFCT-ND RES 27K OHM 1/4W 1% 1206 SMD £0.07
P47.0KFCT-ND RES 47K OHM 1/4W 1% 1206 SMD £0.28
311-82.0KFRCT-ND RES 82.0K OHM 1/4W 1% 1206 SMD £0.07
RMCF1206FT100KCT-ND RES 100K OHM 1/4W 1% 1206 £0.29
RMCF1206FT150KCT-ND RES 150K OHM 1/4W 1% 1206 £0.04
RMCF1206FT200KCT-ND RES 200K OHM 1/4W 1% 1206 £0.20
311-430KFRCT-ND RES 430K OHM 1/4W 1% 1206 SMD £0.07
RMCF1206FT470KCT-ND RES 470K OHM 1/4W 1% 1206 £0.04
RMCF1206FT620KCT-ND RES 620K OHM 1/4W 1% 1206 £0.08
RMCF1206FT1M00CT-ND RES 1M OHM 1/4W 1% 1206 £0.16
311-2.70MFRCT-ND RES 2.70M OHM 1/4W 1% 1206 SMD £0.14
Subtotal £3.20
Shipping £12.00

I think we can share a basket information hope it flips to the USA try this http://www.digikey.co.uk/short/5mp92

[Koala]

working through the IC's

http://www.digikey.co.uk/product-sea...=0&pageSize=25

is 7mV @ 5V the best spec

all other specs are pretty much the same except for the Current - Output (Typ)

[Koala]

working through the IC's

http://www.digikey.co.uk/product-sea...=0&pageSize=25

is 7mV @ 5V the best spec

all other specs are pretty much the same except for the Current - Output (Typ)

Assuming I am right on the above using the best in stock IC's

296-14258-1-ND IC COUNTER/DIVIDER BINRY 14-SOIC 0.29000 £0.29
LM2931AD-5.0R2GOSCT-ND IC REG LDO 5V 0.1A 8SOIC 0.45000 £0.45
296-26732-1-ND IC OPAMP GP 730KHZ RRO 8SOIC 1.31000 £3.93
296-14475-1-ND IC QUAD BILATERAL SWITCH 14-SOIC 0.29000 £0.29
LM393DRCT-ND IC COMPARATOR DUAL 0.8MA 8-SOIC 0.47000 £0.94
MC33178DR2GOSCT-ND IC OPAMP GP 5MHZ 8SOIC 0.60000 £1.20

Subtotal	resistors plus IC's £10.30
Shipping	£12.0 http://www.digikey.co.uk/short/5htd7

[Koala]

0805's seem to be more prevalent. I think they might work as this show they are close in size;

1206 3.0x1.5
0805 2.0x1.3

Ebay has a wider selection of these...

I have some pcb's and some of each type I'll take a look and see if it's workable...

According to this site 0805 are a perfect fit and 2.0 mm × 1.3 mm is the size of the component

[Koala]

Which means we can can go back to Mouser as they have thick film 0805 at £0.05 each and have cheaper shipping

[Silver Dollar]

Oops Sorry I had answered about the 0805's being OK to use but my response didn't show up
(I had some internet problems yesterday).

Thanks for the ordering info. I was able to get the basket with all the parts in it but it's in
british pounds and I'm not sure if it will change it when I order? I have many of the parts
to build the Bandito but I am also building a TGSL SMT at the same time so I think I will install
all the parts I have and then see what I'm missing. I found some SMD 4066's today but will
have to order at least some chips and possibly caps and pots.

I tweaked the layout a bit yesterday and changed all the through-hole caps to SMT. It was tough
as not much room was left. I was hoping to add the second channels to the back of the board
to make the Dual Bandito but it's a bit complicated. I may have to start all over to be able to do that.

I'm not sure I will even have more boards made as no one seems interested in building some. I
probably have enough boards around to do what I need...

[Koala]

Going to start again using Mouser for the cheaper posting.

Just signed up with them and they have an option to share a project

Did you see the all SMT Bandido board at the end of the MD4U thread looks good think it's also proven to work if I remember corectly

[Silver Dollar]

I like Mouser good prices! I didn't know you could share a project. I wonder if you can add two projects together?
I'd like to be able to reorder the same parts again later if I get more boards. Can you order multiples of a project?

I took a copy of that board and am comparing it to our board looking for mistakes + improvements.