Analog Devices ADG413--Incredible Audio Switch IC

Two of my favorite social media (S&M) things: IMSAI Guy's Chip of the Day vlog and finding a great surplus electronics deal on the web. 

This time I do both: my own chip of the day (more like chip of the quarter?  I blame my day job...): an audio/video frequency switch IC I found online at a great surplus price, Analog Device's ADG413BR.

MUX AND FLUX

Audio/digital switch IC's--MUX'es or "multiplexers"--are extremely useful for what we do. The classics contain them; inside Roland's Jupiter 8 (schematic here) and Oberheim's OBXa (here) you find CD4053 and CD4051 mux IC's. 

Details about MCU control of this IC family can be found here and here. 

The ADG413 is a 4-channel switch with superb specs: 50V rail-to-rail supply range compared to the CD4051's 20V, for instance.  

The problem with these high performance switch IC's is their expense. Digikey US sells the ADG413BRZ for $9.08USD in small quantities, compared to 79c each for 4051's on Amazon. 

I'll stick with CD4051's?

Not so fast!! An AudioDiWHY favorite, The Electronic Goldmine, had ADG413BR's on sale recently for $1.79USD each. The 413BR is an obsolete version of the current BRZ IC. The only difference I could see was that the surplus parts were not RoHS compliant. 

(Better to use non-ROHS parts than throw them away--but if they have to go, please get rid of them sensibly....)

An aside: I love The Electronic Goldmine. Hobbyist-friendly surplus stores are a dying breed with many of the great ones like Haltek long gone. Goldmine keeps fighting the good fight. Sign up for their 4AM daily email flyer (here)--good way to start your work day. 

Lifetime buy....

The IC's arrived quickly. I got them ready for the bench.

SOIC: an adapter was needed for breadboarding

Ready to roll....

QUICK WORD FROM THIS BLOG'S SPONSOR

Many thanks to PCBWAY for sponsoring the AudioDiWHY blog and for all the help they've provided over the years. You can help out this blog in a big way by checking out PCBWAY, here. 

As soon as I get my first ADG413 based PCB laid out I'll send the gerber to PCBWAY along with any other fabrication needs, including 3D printing and assembly. 

PCBWAY is super fast, super friendly, and does great work. Please consider using PCBWAY for your next audio project. 

MAKING BALLOON ANIMALS

With two ADG413's soldered up, time to see if I could lay out basic switch circuits.

I still hate breadboarding....

....but I'm slowly getting better. I have found extreme patience, along with using a quality breadboard and checking my work early and often, gets the job done.

Using the 413 to switch LED's off and on (doh). Seems working!

 

Wiring used for ADG413 tests. "IN" represents logic inputs. Yes, the 10K pulldown was necessary; I used 12V for Vdd, GND for VSS, and 5V for logic but found the IC accepted a surprisingly wide range of voltages for rails and logic. Nice! Also, Pins 6/7 are one of 4 I/O pairs and for all I/O audio or DC voltage can flow source to drain or drain to source, makes no difference. 

For breadboarding sanity I used a CD4069 hex inverter for ADG413 pins "IN2" and "IN3". Using an MCU control I'd do this inversion in software.

 A few ideas....

The ADG413 let me create common switch configurations without needing a lot of logic signals:

1-to-4 multiplexer:

Dual SPDT's:

4 SPST's:

DPDT:

1:8 multiplexer using a 74HC595. Use more IC's and get as many channels as you want.

Good tutorial for the 74HC595 IC is here.

OUTTRO

OK enough for now. I bought a lot of ADG413's so (hopefully) they make it into future designs--hours of fun! 

In the meantime, ROHS well, AI well, and above all: don't breathe the fumes.