TEA0679 データシートの表示（PDF） - Philips Electronics

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TEA0679

I2C-bus controlled dual Dolby* B-type noise reduction circuit for playback applications

Philips Electronics 

Philips Semiconductors

I2C-bus controlled dual Dolby* B-type noise

reduction circuit for playback applications

Product specification

TEA0679T

SYMBOL

PARAMETER

CONDITIONS

MIN. TYP. MAX. UNIT

AUTOMATIC MUSIC SEARCH (AMS)

tW(min)(r)

minimum pulse width rise time

AMS(P-M)

AMS(M-P)

signal level at output for AMS

switching pause-to-music

AMS switching hysteresis

music-to-pause

AMS scan mode

AMS latch mode

AMS mode; f = 10 kHz;

notes 3 and 4; see Fig.40

AMS mode; f = 10 kHz

2

−

10

ms

130

−

170

ms

−23.7 −21

−18

dB

−0.7 −1

−1.3 dB

OUTPUT (pin AMS)

VOH

HIGH-level output voltage

IL ≥ −1 mA

VOL

LOW-level output voltage

IL ≤ 1 mA

2.8

−

−

−

3.3

V

0.4

V

Digital part (pins MAD and BEN)

VIH

HIGH-level input voltage

VIL

LOW-level input voltage

IIH

HIGH-level input current

IIL

LOW-level input current

3

−

−0.3 −

−10

−

−10

−

VCC

V

+1.5 V

+10

µA

+10

µA

Digital part (pins SDA and SCL); note 4

VIH

HIGH-level input voltage

BEN (pin 32) open-circuit

3

−

VCC

V

5 V ≤ VBEN ≤ VCC

3

−

VCC

V

3 V ≤ VBEN < 5 V

0.7VBEN −

VCC

V

VIL

LOW-level input voltage

BEN (pin 32) open-circuit

−0.3 −

+1.5 V

5 V ≤ VBEN ≤ VCC

−0.3 −

+1.5 V

3 V ≤ VBEN < 5 V

−0.3 −

0.3VBEN V

IIH

HIGH-level input current

VCC = 0 to 12 V

−10

−

+10

µA

IIL

LOW-level input current

−10

−

+10

µA

VOL

LOW-level output voltage SDA IL = 3 mA

−

−

0.4

V

Notes

1. For Dolby NR level adjust and AMS pause detection level setting.

2. All blank skip timing characteristics are based on the assumption that a signal level change from −33 to −21 dB

pause-to-music or −21 to −33 dB music-to-pause occurs in the specified channels.

3. The high speed of the tape (FF and REW) at the tape head during AMS mode causes a transformation of level and

frequency of the originally recorded signal. It means a boost of signal level of approximately 10 dB and more for

recorded frequencies from 500 Hz to 4 kHz. So the threshold level of −22 dB corresponds to signal levels in PlayBack

(PB) mode of approximately −32 dB. The AMS inputs for each channel are pins SCA and SCB. As the frequency

spectrum is transformed by a factor of approximately 10 to 30 due to the higher tape speed in FF and REW, the

high-pass filter (4.7 nF/24 kΩ) removes the effect of offset voltages but does not affect the music search function.

In the block and application diagram (see Fig.1) the frequency response of the system between tape heads input,

e.g. pins INA2 and INB2, to the AMS input pins SCA and SCB is constant over the whole frequency range (see

Fig.3).

4. These levels correspond to a gain setting of Dolby level at TP (for TP see Fig.41). The gain adjustment can be used

to change the threshold level during AMS operation.

5. The characteristics are in accordance with the I2C-bus specification. Information about the I2C-bus can be found in

the brochure “The I2C-bus and how to use it” (order number 9398 393 40011).

1998 Nov 12

9

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