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PDF NJU8721 Data sheet ( Hoja de datos )
| Número de pieza | NJU8721 | |
| Descripción | Class D HeadPhone Amplifier for Digital Audio | |
| Fabricantes | New Japan Radio | |
| Logotipo |  |
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Hay una vista previa y un enlace de descarga de NJU8721 (archivo pdf) en la parte inferior de esta página. Total 14 Páginas | ||
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NJU8721
PRELIMINARY
CLASS D HEADPHONE AMPLIFIER FOR DIGITAL AUDIO
! GENERAL DESCRIPTION
The NJU8721 is a class D Headphone Amplifier
featuring 6th ∆Σ modulation. It includes Digital
Attenuator, Mute, and De-emphasis circuits. It
converts digital source input to PWM signal output
which is converted to analog signal with simple
external LC low-pass filter. The NJU8721 realizes
very high power-efficiency by class D operation.
Therefore, it is suitable for portable audio set and
others.
! PACKAGE OUTLINE
NJU8721V
! FEATURES
# Stereo Headphone Power Amplifier
: 50mW+50mW
# Sixth-order 32fS Over Sampling ∆Σ & PWM
# Internal 8fS Over Sampling Digital Filter
# Sampling Frequency : 96kHz (Max.)
# De-Emphasis
: 32kHz, 44.1kHz, 48kHz
# System Clock
# Digital Processing
: 256fS
: Attenuator 107step, LOG Curve
: Mute
# Digital Audio Interface : 16bit, 18bit
: I2S, LSB Justified, MSB Justified
# Operating Voltage : 2.4 to 3.6V
# Driving Voltage
: VDD to 5.25V
# C-MOS Technology
# Package Outline
: SSOP20 / QFN28
NJU8721KN1
! PIN CONFIGURATION
STBY
TEST
VSSR
OUTR
VDDR
VDDL
OUTL
VSSL
MODE
RST
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
SSOP20
VDD
F0/DATA
F1/REQ
F2/SCK
MUTE
DIN
LRCK
BCK
MCK
VSS
28
1
VSSR
OUTR
VDDR
NC
VDDL
OUTL
VSSL
F1/REQ
F2/SCK
MUTE
NC
DIN
LRCK
BCK
QFN28
Ver.2003-08-28
-1-
1 page  
NJU8721
(6) System Control
(6-1) Standby
Standby functions by “L” level input to the STBY terminal. In busy of Standby, conditions of digital audio
format set, attenuation level, de-emphasis, and attenuator operation time are kept and output terminals of
OUTL and OUTR are high-impedance.
(6-2) Control Mode Set
A control mode as shown below is selected by the MODE terminal.
MODE
0
1
Control Method
Parallel
Serial
Function
Digital Audio interface Format Set
Control Register serial data input
Terminals
F0, F1, F2
DATA, REQ, SCK
Parallel
Serial
: Digital Audio Interface Format is set directly by using F0, F1, and F2 terminals.
: NJU8721 is controlled serial input data by 3-wire serial interface using DATA, REQ, and
SCK terminals
By this setting, the function of F0/DATA, F1/REQ, and F2/SCK are changed.
Refer to (8-5)F0,F1,F2 about function of F0, F1, and F2 terminals.
Refer to (8)Control Register about function of DATA, REQ, and SCK terminals.
(6-3) Mute
Mute functions by “L” signal into the MUTE terminal. In busy of mute, a current attenuation value
becomes -∞ by internal digital attenuator. And MUTE is stopped by “H” signal into the MUTE terminal, the
attenuation value returns from -∞ to previous value.
MUTE
0
1
Attenuation Level
-∞
Set Value
MUTE
MCK
Attenuation Value
Set Value
1024/fS
-∞
1024/fS
Set Value
-∞
Figure 2. Mute Timing
Ver.2003-08-28
-5-
5 Page 
NJU8721
Note 6) Analog AC Characteristics Test System
Analog AC characteristics test system is shown in Figure 6. The analog AC characteristics of NJU8721
is measured with 2nd-order LC LPF on the test board and Filters in the Audio Analyzer.
Digital
Data
Digital Audio
Interface
Receiver Chip
NJU8721
2nd-order
LC LPF
Filters
THD
Measuring
Apparatus
NJU8721 Evaluation Board
Audio Analyzer
Figure 6. Analog AC Characteristics Measurement System
2nd-order LPF
Filters
: fc=34kHz, refer to the LPF on Application Circuit.
: 22Hz HPF + 20kHz 10th-order LPF
(with the A-Weighting Filter at measuring S/N and Dynamic-range)
Ver.2003-08-28
- 11 -
11 Page | ||
| Páginas | Total 14 Páginas | |
| PDF Descargar | [ Datasheet NJU8721.PDF ] | |
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