參數(shù)資料
型號(hào)： TDA9885
廠商： NXP Semiconductors N.V.
英文描述： I2C-bus controlled single and multistandard alignment-free IF-PLL demodulators
中文描述： 的I2C控制的單一和多路巴士免費(fèi)中頻鎖相環(huán)解調(diào)器
文件頁(yè)數(shù)： 13/56頁(yè)
文件大小： 248K
代理商： TDA9885
2003 Oct 02
13
Philips Semiconductors
Product specification
I
2
C-bus controlled single and multistandard
alignment-free IF-PLL demodulators
TDA9885; TDA9886
8.14
Audio amplifier and mute time constant
The audio amplifier consists of two parts:
AF preamplifier
AF output amplifier.
The AF preamplifier used for FM sound is an operational
amplifier with internal feedback, high gain and high
common mode rejection. The AF voltage from the
PLL demodulator is 5 mV (RMS) for a frequency deviation
of 27 kHz and is amplified by 30 dB. By the use of a
DC operating point control circuit (with external
capacitor C
AF
), the AF preamplifier is decoupled from the
PLL DC voltage. The low-pass characteristic of the
amplifier reduces the harmonics of the sound intercarrier
signal at the AF output terminal.
For FM sound a switchable de-emphasis network (with
external capacitor) is implemented between the
preamplifier and the output amplifier.
The AF output amplifier provides the required AF output
level by a rail-to-rail output stage. A preceding stage
makes use of an input selector for switching between
FM sound, AM sound and mute state. The gain can be
switched between 10 dB (normal) and 4 dB (reduced).
Switching to the mute state is controlled automatically,
dependent on the digital acquisition help in case the VCO
of the FM-PLL is not in the required frequency window.
This is done by a time constant: fast for switching to the
mute state and slow (typically 40 ms) for switching to the
no-mute state.
All switching functions are controlled via the I
2
C-bus:
AM sound, FM sound and forced mute
Auto mute enable or disable
De-emphasis off or on with 50 or 75
μ
s
Audio gain normal or reduced.
8.15
Internal voltage stabilizer
The band gap circuit internally generates a voltage of
approximately 2.4 V, independent of supply voltage and
temperature. A voltage regulator circuit, connected to this
voltage, produces a constant voltage of 3.55 V which is
used as an internal reference voltage.
8.16
I
2
C-bus transceiver and module address
The device can be controlled via the 2-wire I
2
C-bus by a
microcontroller. Two wires carry serial data (SDA) and
serial clock (SCL) information between the devices
connected to the I
2
C-bus.
The device has an I
2
C-bus slave transceiver with
auto-increment. The circuit operates up to clock
frequencies of 400 kHz.
A slave address is sent from the master to the slave
receiver. To avoid conflicts in a real application with other
devices providing similar or complementing functions,
there are four possible slave addresses available. These
Module Addresses (MADs) can be selected by connecting
resistors on pin SIOMAD and/or pins SIF1 and SIF2 (see
Fig.23). Pin SIOMAD relates with bit A0 and pins SIF1
and SIF2 relate with bit A3. The slave addresses of this
device are given in Table 1.
The power-on preset value is dependent on the use of
pin SIOMAD and can be chosen for 45.75 MHz NTSC as
default(pin SIOMADleftopen-circuit)or58.75 MHzNTSC
(resistor on pin SIOMAD). In this way the device can be
used without the I
2
C-bus as an NTSC only device.
Remark:
In case of using the device without the I
2
C-bus,
then the rise time of the supply voltage after switching on
power must be longer than 1.2
μ
s.
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
TDA9885HN/V3 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:I2C-bus controlled single and multistandard alignment-free IF-PLL demodulators
TDA9885HN/V3,118 功能描述:調(diào)節(jié)器/解調(diào)器 TDA9885HN/HVQFN32/REEL13//V3 RoHS:否 制造商:Texas Instruments 封裝 / 箱體:PVQFN-N24 封裝:Reel
TDA9885HN/V3,518 功能描述:調(diào)節(jié)器/解調(diào)器 DEMODUL NEG MODULTN RoHS:否 制造商:Texas Instruments 封裝 / 箱體:PVQFN-N24 封裝:Reel
TDA9885HN/V3/S1,11 功能描述:調(diào)節(jié)器/解調(diào)器 DEMODUL NEG MODULTN RoHS:否 制造商:Texas Instruments 封裝 / 箱體:PVQFN-N24 封裝:Reel
TDA9885HN/V3/S1-T 功能描述:調(diào)節(jié)器/解調(diào)器 DEMODUL NEG MODULTN VIF AND SIF RoHS:否 制造商:Texas Instruments 封裝 / 箱體:PVQFN-N24 封裝:Reel
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