AS “АLFA RPAR”

Joint Stock Company ALFA

Riga, Latvia www.alfarzpp.lv; alfa@alfarzpp.lv

1

2019 v.1

AS3394E

AS3394E

AS3394E

µP CONTROLLABLE SYNTHESIZER VOICE

FEATURES

AS3394ED

•

Complete synthesizer Voice on a Chip

•

Sample & Hold buffers on-chip for easy interface to a

µP

•

Fully temperature compensated VCO

•

Independently selectable VCO waveforms

•

Sub-oscillator output

•

Separate saw-tooth output

•

Separate VCO and filter sections allowing design flexibility

•

Constant Loudness vs Resonance VCF

•

Rich Sounding VCF Design

•

Filter FM routing for more Timbres

SOIC-24 300mil, 1.27 mm

DESCRIPTION

The AS3394E is a complete analog music synthesizer voice-on-a-chip intended for software control by

a microprocessor system. Included inside the compact 24 pin package is fully temperature compensated, wide

range, voltage controlled oscillator providing sub-oscillator, triangle, saw-tooth, and pulse waveforms;

a voltage controlled mixer for adjusting the balance between the internally generated VCO waveforms and any

external signal; a dedicated four-pole low-pass voltage controlled filter with voltage controlled resonance; a

modulation amount VCA for modulating the filter frequency by the triangle waveform output of the VCO; and a

final VCA for allowing the output to be enveloped. Envelope control for both the VCF and final VCA may be

provided by either a hardware envelope generator such as the AS3310 or through software.

All eight control inputs are provided with internal very high input impedance, low bias current buffers. Thus

interface to a microprocessor system may be accomplished simply with a single DAC, 4051-type CMOS

multiplexer, and 8 hold capacitors.

Requiring a bare minimum of other external components, the AS3394E is ideal for low cost polyphonic or

polytimbric musical instruments featuring rich, analog sound.

FUNCTIONAL BLOCK DIAGRAM

+

+

-

7

V+

11

12

10

9

8

V-

X

11K

D-Trig

TC

GEN

B

B

B

B

B

B

B

B

B

TRNGL.

TRNGL.

ICO

to saw

conv.

4 LEVEL

TRANSLATE

VCA2

VCA3

S1

S2

S3

VCA5

e

x

-

-

ΔGm

ΔGm

ΔGm

ΔGm

-

+

+

+

+

+

-

-

-

-

+

VCA4

1K

1K

VCA1

-

1K

AS3394E

1K

24

22

21

20

23

19

18

17

16

15

14

13

1

2

3

4

5

6