RPi-DAC SingleStereo DAC rev. 6solder with 1m and 47m (on In and Out) , check voltages before soldering other parts

solder all other parts, excluding the active components such as OpAmp, PCM1794A ad TPA6120A

measure again all voltages: 2x +15C, 2x -15V, 1x6V, 1x3.3V

if all OK, solder OpAmp, PCM1794A and TPA6120A

power always all rails, esp. the + and -15V,

all LDOs first

never power just one rail

Solder Options:

if fed with DC: the BRECT and electrolyte caps are not needed: use 0R instead of BRECT

not all 47m (or 1m) Cb are needed, some can be omitted

For I/V converter (4x OpAmp) use OPA827 or LME49990

the LEDs (as indicators for the power rails) plus R can be optional

the jumper headers and jumpers can be fix soldered as 0R

the OSC (XTAL) is not used or needed, just if external FPGA or other components

some Cb (1206) as 47m/25V can be also changed to 68m/10V (depends on which rail used)

all Cb (0603) without value mentioned can be 0.1m or 1m (ATT: one 1m used on LDOs)

Improvements:

Use metal film resistors if located in signal path (825R, 1K, 1.5K, 10R)

Use NPO/CG0 caps (5.6n) if in signal path

Use OPA827 instead of LME49990 for I/V converter (JFET, but higher noise and THD)

Attention:

Use AC or DC in for the +15 and -15V railwithout any common center tap (with separated coils),no common connection between both!

RPi-DAC SingleStereo Top

OpAmp OpAmp

OpAmpOpAmp

TPA6120A

PC

M1794A

+

+

+

+

C (0603)

R (0603)

Cb (1206)47m/25V

male header + jumper

LED (0603)

male connector

female connector

OSC

33R

33R

33R

33R

10K

10K

10K

10K

10K

10K

10K

8.2K

825R 825R

5.6n 5.6n

825R 825R

5.6n 5.6n130R

1.3K

1.3K

1.3K

10R

10R

1K1K

1K 1K

1.5K

1.5K

1.5K

1.5K

1.3K

+

+

+

+

BRECT

BRECT

BR

EC

T

BR

EC

Toptional

Cb (0603) 0.1..1m

+

1m

1m 1m

1m

1m

1m

+ -GND

GND + -

LDO

LDO

LDO

LDOLDO

LDO

GND

GNDn.c.

n.c.

HeadphoneRCA Out

I2S In

OpAmp: OPA827 or LME49990

3.3V

6V

+15V

-15V

-15V

+15V

solder LDO first and measure voltage

47m47m

LDO : TPS7A4700

6V

6V

6V

GND

6V

AC6..9V

AC15V

AC15V

BCK

LRCK

DATA

5V

3.3V

n.c.

sep

ara

ted

co

ils!

ACs in for the +15 and -15V rails have to comefrom separated coils, no center tap, no commonGND or connection!

RPi-DAC SingleStereo Bottom solder power pad before electrolyte

electrolyte just if AC input, with DC not neededoptional

+ +

+

+

+ +

+

+

+

6V

3.3V

+ grounded

+ grounded

RPi-DAC SingleStereo Top

RPi-DAC SingleStereo Bottom

PCM1794A 15P

15N

+3.3V

+6V

+15V

-15V

I2S

OUTR

+7V

+16V

1A

+DVDD

+AVDD

AGND

AGND

DGND

DGND

AGND

R+

R-

AGND

AGND

15P

15N

OUTL

AGND

L+

L-

AGND

TPS7A4700

+15V

-15V

6x TPS7A4700

+16V

AGND

OUTR

OUTL

4x LME49990 TPA6120A

RPi-DAC

24bit, 192KHz

0.0004% THD+N120dB Channel Sep.?? PSRR?? Noise

127dB SNR

127dB CMRR0.00001% THD+N-144dB PSRR1.3nV/sqrt(Hz)

-79dB PSRR

120dB SNR0.0006% THD+N

5mVrms Noise

+16VTPS7A4700

TPS7A4700

TPS7A4700

TPS7A4700

TPS7A47001A

1A

1A

1A

1A

FMT

-82dB PSRR (100Hz)4.17mVrms Noise

Headphone:Sennheiser HD800

300Ohm0.02% THD

+6V

I/V Converter

+

+

-16V

+16V

-16V

+6V

+3.3V

MONO

CHSL

DEM

LRCK

DATA

BCK

SCK

DGND

VDD

MUTE

FMT0

FMT1

ZERO

/RST

VCC2L

AGND3L

IOUTL-

IOUTL+

AGND2

VCC1

VCOML

VCOMR

IREF

AGND1

IOUTR-

IOUTR+

AGND3R

VCC2R

1

2

3

4

5

6

7

8

9

10

11

12

13

14 15

16

17

18

19

20

21

22

23

24

25

26

27

28PCM1794A

3.3V

3.3V

3.3V

6V

6V

6V

AGND

AGND

AGND

AGND

AGND

DGND

DGND

DGND

DGND

AGND

AGND

15P

15N

-

+

15P

15N

-

+

15P

15N

-

+

15P

15N

-

+

LVCC-

LOUT

LVCC+

LIN+

LIN-

n.c.

RVCC-

ROUT

RVCC+

RIN+

RIN-

1

2

3

4

5

6

7

8

9

10 11

12

13

14

15

16

17

18

19

20TPA6120A

n.c.

n.c.

n.c.

n.c.

n.c.

n.c.

n.c.

n.c.

n.c.

POWERPAD

OUTR+

OUTR-

OUTR

15P

15N

gain: 2.5V/V

LRCK

DATA

BCK

SCK

IOUTL-

IOUTL+

IOUTL+

IOUTL-

10K

10K 10K

10K

33R

33R

33R

33R

10K

47m

47m

10K

10..30R

825R

10K

4x LME49990

15N

OUTL-

OUTL+

OUTR+

OUTR-15P

OUTL

OUTL+

OUTL-

47m

47m

47m

47m

100n

100n

100n

100n

47m

47m

100n

100n

100n

100n

47m

47m

100n

100n

100n

100n

100n

100n

2

3

6

7

4

2

3

6

7

4

4

72

3

6

6

7

4

2

3

100n

100n

AGND

AGND

AGND

AGND

RPi-DAC SingleStereo

Ipp = 7.8mA

f =34.5KHz

Vpp = * -7.8mAVrms = Vpp / sqrt(2)

825R

keep Vrms ~ 8V (<9V)

keep Vpp ~ 17V

keep Vpp < 3.5...4V

keep gain: 2..3V/V

I2S

J1

J2

10K

1K

5.6n

1K

1.5K

1.5K

1.5K

1K

1K

1.5K

10..30R

825R

825R

825R

5.6n

5.6n

5.6n

8.2K

or: 4x OPA827

CG0/NPOmetal film

1

56 10

11

151620

C147m

IN

C247m

OUT

SENSE

C31m

NR

6.4V2

6.4V1

3.2

V

1.6

V

0.8

V

0.4

V

0.2V

0.1V

EN

nc

nc nc nc

TPS7A4700 (pos.)

VOUT = + /Vpin1.4V

+15V

1

56 10

11

151620

C147m

IN

C247m

OUT

SENSE

C31m

NR

6.4V2

6.4V1

3.2

V

1.6

V

0.8

V

0.4

V

0.2V

0.1V

EN

nc

nc nc nc

TPS7A4700 (pos.)

VOUT = + /Vpin1.4V

6VPSRR: Vnoise:

78dB4.67 mVrms

AC

3x separate coils!

DC

47m47m820m820m

1m 1m

2A

DC DC

6x TPS7A4700 (pos.)

4x Bridge Rectifier

1A 1A

PSU (low noise LDOs)

4x

1

56 10

11

151620

C147m

IN

C247m

OUT

SENSE

C31m

NR

6.4V2

6.4V1

3.2

V

1.6

V

0.8

V

0.4

V

0.2V

0.1V

EN

nc

nc nc nc

TPS7A4700 (pos.)

VOUT = + /Vpin1.4V

3.3VPSRR: Vnoise:

78dB4.67 mVrms

1m

DC

1A

on -15V rail - the GND is used, +15V is grounded!

-15V

RPi-DAC SingleStereo Pictures