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UDA1334ATS

Low power audio DAC with PLL

Philips Electronics 

Philips Semiconductors

Low power audio DAC with PLL

Product specification

UDA1334ATS

8.4 Filter stream DAC

The FSDAC is a semi-digital reconstruction filter that

converts the 1-bit data stream of the noise shaper to an

analog output voltage. The filter coefficients are

implemented as current sources and are summed at

virtual ground of the output operational amplifier. In this

way very high signal-to-noise performance and low clock

jitter sensitivity is achieved. No post filter is needed due to

the inherent filter function of the DAC. On-board amplifiers

convert the FSDAC output current to an output voltage

signal capable of driving a line output.

The output voltage of the FSDAC scales proportionally to

the power supply voltage.

8.5 Power-on reset

The UDA1334ATS has an internal Power-on reset circuit

(see Fig.3) which resets the test control block.

The reset time (see Fig.4) is determined by an external

capacitor which is connected between pin Vref(DAC) and

ground. The reset time should be at least 1 µs for

Vref(DAC) < 1.25 V. When VDDA is switched off, the device

will be reset again for Vref(DAC) < 0.75 V.

During the reset time the system clock should be running.

handbook, halfpage

3.0 V

VDDA

13

Vref(DAC) 12

50 kΩ

RESET

CIRCUIT

C1 >

10 µF

50 kΩ

UDA1334ATS

MGT015

Fig.3 Power-on reset circuit.

3.0

handVbDooDk,Dhalfpage

(V)

1.5

0

t

3.0

VDDA

(V)

1.5

0

3.0

Vref(DAC)

(V)

1.5

1.25

0.75

0

>1 µs

Fig.4 Power-on reset timing.

t

t

MGL984

2000 Jul 31

8

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