17.1Introduction to soldering surface mount
packages
17.2Reflow soldering
17.3Wave soldering
17.4Manual soldering
17.5Suitability of surface mount IC packages for
wave and reflow soldering methods
18DEFINITIONS
19LIFE SUPPORT APPLICATIONS
20PURCHASE OF PHILIPS I2C COMPONENTS
1999 Apr 142
Philips SemiconductorsProduct specification
Audio processor with head amplifier for VHS hi-fiTDA9605H
1FEATURES
• All functions controlled via the serial 2-wire I2C-bus
• Integrated standby modes for low power consumption
• Audio FM head amplifier:
– Programmable recording current
– Programmable playback amplification
– Fast record-mute mode control input.
• Hi-fi signal processing:
– Adjustment free
– High performance
– Low distortion switching noise suppressor
– NTSC and PAL (SECAM) system.
• Linear audio input:
– Programmable (playback) level.
• 5 stereo inputs and additional mono Second Audio
Program (SAP) input
• 2 stereo outputs (line and decoder) with independent
output select function
• RF converter output with overload-protection AGC
• Integrated output power muting
• Audio level meter output
• Extensive input and output select function
• Full support of video recorder feature modes.
2GENERAL DESCRIPTION
The TDA9605H is a single-chip device in a small package
that contains all the required functions, including the head
amplifier, to realize the audio FM hi-fi stereo system in a
VHS video recorder (see Fig.1). The device is adjustment
free by use of an integrated auto-calibration system.
Extensive signal select functions are offered to support
pay-TV decoding and video recorder feature modes.
The high performance and functionality of the TDA9605H
comprises world-wide system and application
requirements for NTSC, PAL, SECAM and multi-standard
video recorders from basic up to high-end models.
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1999 Apr 144
V
CCH
GNDH
PBIN1
PBIN2
RECOUT
HMSW
SAP
TUNL
TUNR
CINL
CINR
EXT1L
EXT1R
EXT2L
EXT2R
AUXL
AUXR
40
39
37
35
36
38
playback. +
record-mute,
recording
1
2
3
4
5
6
7
8
9
10
11
SAP
TUL
TUR
E1L
E1R
E2L
E2R
HEAD AMPLIFIER
input select
I2C-bus
control
RMHID
41444243
DCL
HID
current
RM
M
HID
DCR
HF AGC
1.3 or 1.4 MHz
+
1.7 or 1.8 MHz
RM
playback head
amplification,
record head
carrier ratio select,
record-mute
FM (DE-)MODULATOR
volume left
M
M
volume right
M
normal select
TUL
TUR
E2L
E2R
N
dub
M
+
+
= mute
+
SAP
ENVOUT
envelope
output
select
+ playback
LEVEL
DETECTOR
HF LIMITER
HF LFP
LEVEL
DETECTOR
HF LIMITER
HF LFP
+++
I/O CONTROL
normal
input
level
2122
LINOUT LININ
HI-FI
DETECTOR
DROPOUT
CANCELING
PLL
CCO
(1.3 or
1.4 MHz)
PLL
CCO
(1.7 or
1.8 MHz)
M
dbook, full pagewidth
SDA SCL
I2C-BUS
INTERFACE
AUTN
HID
NOISE
SUPPRESSION
AUDIO
CLIPPER
NOISE
SUPPRESSION
AUDIO
CLIPPER
output selectAUTN
L
R
+
N
envelope output
select + record
L
R
PEAK HOLD
PEAK HOLD
TDA9605H
V
CC
34272928
standby select
5th ORDER
AUDIO LPF
COMPRESSOR
5th ORDER
AUDIO LPF
COMPRESSOR
dub
M
DCL
DCR
GND
SUPPLY
NOISE REDUCTION
W + FM
EXPANDER
W + FM
EXPANDER
TUL
E1L
SAP
TUR
E1R
SAP
E2L
E2R
mute
V
CC
RFCAGC
V
ref
DETECTOR
RECTIFIER
CCA
DETECTOR
RECTIFIER
CCA
decoder
select
M
line select
AUTO-MUTE
M
RF converter
mute
12
I
ref
+1 dB 12 V
26
25
24
23
30
31
32
33
19
20
16
15
17
18
13
14
MGR834
DETL
DCL
EMPHL
DCFBL
DETR
DCR
EMPHR
DCFBR
DECL
DECR
LINEL
MUTEL
LINER
MUTER
RFCOUT
MUTEC
4BLOCK DIAGRAM
Audio processor with head amplifier for VHS hi-fiTDA9605H
Philips SemiconductorsProduct specification
Fig.1 Block diagram.
Philips SemiconductorsProduct specification
Audio processor with head amplifier for VHS hi-fiTDA9605H
5PINNING
SYMBOL PINDESCRIPTION
SAP1tuner input mono
TUNL2tuner input left
TUNR3tuner input right
CINL4CINCH input left
CINR5CINCH input right
EXT1L6external 1 input left
EXT1R7external 1 input right
EXT2L8external 2 input left
EXT2R9external 2 input right
AUXL10auxiliary input left
AUXR11auxiliary input right
RFCAGC12RF converter AGC timing connection
RFCOUT13RF converter output
MUTEC14mute for RF converter output
MUTEL15mute for line output left
LINEL16line output left
LINER17line output right
MUTER18mute for line output right
DECL19decoder output left
DECR20decoder output right
LINOUT21linear audio output
LININ22linear audio input
DCFBL23DC feedback noise reduction
connection left
EMPHL24emphasis noise reduction connection
left
SYMBOL PINDESCRIPTION
DCL25DC decoupling noise reduction
connection left
DETL26detector noise reduction connection
left
GND27ground
I
ref
V
ref
28reference standard current connection
29reference voltage connection
DETR30detector noise reduction connection
right
DCR31DC decoupling noise reduction
connection right
EMPHR32emphasis noise reduction connection
right
DCFBR33DC feedback noise reduction
connection right
V
CC
34power supply
PBIN235head 2 playback input
RECOUT36recording current output
PBIN137head 1 playback input
HMSW38head amplifier mode switch connection
GNDH39ground of head amplifier
V
CCH
40power supply of head amplifier
RMHID41record-mute mode or head
identification input
SDA42I2C-bus data input/output
SCL43I
2
C-bus clock input
ENVOUT44HF or AF envelope output
1999 Apr 145
Philips SemiconductorsProduct specification
Audio processor with head amplifier for VHS hi-fiTDA9605H
handbook, full pagewidth
SAP
TUNL
TUNR
CINL
CINR
EXT1L
EXT1R
EXT2L
EXT2R
AUXL
AUXR
SDA
ENVOUT
SCL
44
43
42
1
2
3
4
5
6
7
8
9
10
11
12
13
14
MUTEC
RFCAGC
RFCOUT
CCH
RMHID
V
41
40
TDA9605H
15
16
LINEL
MUTEL
GNDH
39
17
LINER
PBIN1
HMSW
38
37
18
19
DECL
MUTER
RECOUT
36
20
DECR
CC
V
PBIN2
35
34
21
22
LININ
LINOUT
33
DCFBR
EMPHR
32
31
DCR
30
DETR
V
29
28
I
GND
27
DETL
26
DCL
25
24
EMPHL
DCFBL
23
MGR835
ref
ref
Fig.2 Pin configuration.
6FUNCTIONAL DESCRIPTION
Input and output selections for the various modes are given in the following diagrams:
• Standard operating mode (see Fig.3)
• Dub-mix mode (see Fig.4)
• Standby mode: active or passive (see Fig.5).
1999 Apr 146
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1999 Apr 147
TUNL
TUNR
CINL
CINR
EXT1L
EXT1R
EXT2L
EXT2R
SAP
AUXL
AUXR
(1)
input select
TUNER
CINCH
EXT1
EXT2
SAP
AUX
DUB MIX
NORMAL
volume left
MUTE
(−47 to 0 dB;
0 to +15 dB)
MUTE
(−47 to 0 dB;
0 to +15 dB)
volume right
RECOUT
ok, full pagewidth
tape
PBIN1
PBIN2
HI-FI
AUDIO FM
PROCESSING
output select
MUTE
LEFT
RIGHT
STEREO
NORMAL
NORMALLEFT
NORMALRIGHT
NORMALSTEREO
decoder select
TUNER
EXT1
SAP
MUTE
OUTPUT SELECT
line select
EXT2
OUTPUT SELECT
RF converter AGC
0 dB AGC
MUTE
line output
amplification
0 dB
+1 dB
RFCOUT
Philips SemiconductorsProduct specification
Audio processor with head amplifier for VHS hi-fiTDA9605H
DECL
DECR
LINEL
LINER
(1) For dub-mix mode signal selections see Fig.4.
normal input levelnormal select
INPUT SELECT
INPUT LEFT
VOLUME
VOLUME LEFT
SAP
TUNER
EXT2
MUTE
LINOUT
MUTE
(0 to +14 dB)
LININ
linear audio
processing
Fig.3 Input and output selections for standard operating mode.
envelope select
OUTPUT SELECT
STEREO
HF ENVELOPEHF envelope
MGR836
ENVOUT
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1999 Apr 148
, full pagewidth
Philips SemiconductorsProduct specification
Audio processor with head amplifier for VHS hi-fiTDA9605H
TUNL
TUNR
CINL
CINR
EXT1L
EXT1R
EXT2L
EXT2R
SAP
AUXL
AUXR
input select
DUB MIX
volume auxoutput select
MUTE
(−47 to 0 dB;
0 to +15 dB)
MUTE
(−47 to 0 dB;
0 to +15 dB)
volume hi-fi
INPUT SELECT
INPUT LEFT
VOLUME
VOLUME LEFT
SAP
TUNER
EXT2
MUTE
RECOUT
PROCESSING
normal input levelnormal select
LINOUT
linear audio
processing
(record)
tape
PBIN1
PBIN2
HI-FI
AUDIO FM
(playback)
MUTE
(0 to +14 dB)
LININ
MUTE
LEFT
RIGHT
STEREO
NORMAL
NORMAL
NORMAL
NORMAL
MUTE
LEFT
RIGHT
LEFTRIGHT
MUTE
LEFT
RIGHT
LEFTRIGHT
decoder select
TUNER
EXT1
SAP
MUTE
OUTPUT SELECT
line select
EXT2
OUTPUT SELECT
RF converter AGC
0 dB AGC
MUTE
envelope select
OUTPUT SELECT
STEREO
HF ENVELOPEHF envelope
MGR837
line output
amplification
0 dB
+1 dB
RFCOUT
ENVOUT
DECL
DECR
LINEL
LINER
Dub-mix mode: IS2 =1, IS1 = 0 and IS0 = 1.
Input mixing of the hi-fi (playback) signal with the auxiliary, used for linear audio dubbing recording.
Selections generally used in combination with dub-mix mode are shown in heavy line type.
Fig.4 Input and output selections for dub-mix mode.
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1999 Apr 149
TUNL
TUNR
CINL
CINR
EXT1L
EXT1R
EXT2L
EXT2R
SAP
AUXL
AUXR
input select
MUTE
handbook, full pagewidth
output select
MUTE
decoder select
TUNER
EXT1
SAP
MUTE
OUTPUT SELECT
line select
EXT2
OUTPUT SELECT
RF converter AGC
MUTE
MGR838
line output
amplification
0 dB
+1 dB
a. Active standby mode (bit STBA = 1, bit STBP = 0); over 80% power reduction.
Philips SemiconductorsProduct specification
Audio processor with head amplifier for VHS hi-fiTDA9605H
DECL
DECR
LINEL
LINER
RFCOUT
TUNL
TUNR
CINL
CINR
EXT1L
EXT1R
EXT2L
EXT2R
SAP
AUXL
AUXR
input select
MUTE
b. Passive standby mode (bit STBP = 1); over 90% power reduction.
Fig.5 Input and output selections for standby modes.
Philips SemiconductorsProduct specification
Audio processor with head amplifier for VHS hi-fiTDA9605H
6.1Record-mute mode or head identification
selection
Pin RMHID allows input of two independent digital control
signals for selecting the record-mute or head identification
modes which are voltage coded. The RM control signal is
selected via a 10 kΩ resistor and the HID control signal is
selected via a 18 kΩ resistor. This set-up enables the two
signals within the TDA9605H to be separated. The RM
control signal is only in use during the record mode
(bit AFM = 1); during the playback mode (bit AFM = 0) the
RM signal is ignored. Pin RMHID should be connected to
ground when the RM control signal is not used.
The use of the RM control signal is optional since the same
function is available via the I
2
C-bus control in the
record-mute mode. However, accurate timing of recording
start and stop may sometimes be difficult to realize via the
I2C-bus control. In this event the RM control signal can be
used instead. There is also the possibility to use the
record-mute mode control line of the video head amplifier.
6.2Hi-fi audio output level
When the application circuit is used in accordance with the
application diagram, the standard FM deviation of 50 kHz
equals a 1 kHz audio signal of −8 dBV line output level
(bit LOH = 0). A different standard audio level can be
selected by changing the external filter components of the
noise reduction on pins EMPHL and EMPHR
(see Section 14.3). The standard audio level changes
proportionally to the impedance of the external
de-emphasis filter.
6.3Reference current
The external resistor connected to pin I
defines the
ref
internal reference currents and determines the
temperature stability of circuits adjusted by the
auto-calibration function.
6.4Head amplifier
6.4.1PLAYBACK MODE
The playback mode is selected by setting bit AFM = 0.
During the playback mode the input circuit on pins PBIN2
and PBIN1 is enabled (see Fig.6). Pin RECOUT is
disabled and pin HMSW shows a low impedance to
ground, so realizing an AC ground for the head circuit via
the external capacitor connected between these pins.
The head identification (HID) signal on pin RMHID selects
between the head signals on pins PBIN2 or PBIN1. Head
selection is defined as shown in Table 1.
The state of the RM control signal on pin RMHID is don’t
care in the playback mode.
2
I
C-bus control bits HAC2, HAC1 and HAC0 offer a wide
selection of playback amplification to fit different head and
head transformer specifications. The advised setting of the
playback amplification realizes a level of 24 mV (RMS) for
each carrier signal after the head amplifier to obtain a
17 dB overhead compared to the auto-normal level (hi-fi
detection). However, performance is not critical and a
different setting can be used if desired.
The carrier level can be measured using the HF envelope
output voltage on pin ENVOUT (bit EOS = 1). During
standard operating mode the HF envelope signal is
derived from the left channel carrier amplitude
(1.3 or 1.4 MHz carrier) but the special test 10 of the test
mode also enables the HF envelope output of the right
channel carrier amplitude (1.7 or 1.8 MHz carrier).
The advised carrier playback level of 24 mV (RMS) equals
an HF envelope voltage of 3.3 V.
The head amplifier output signal can be monitored directly
by using test 8 of the test mode. Pin ENVOUT functions as
the test output showing 6 dB attenuation compared to the
actual head amplifier output level (see Section 14.4).
Table 1Selection of the head signal
HID
SIGNAL
LEVEL ON PIN RMHID
LOWlower than 0.6 V or
between 2.65 and 3.8 V
HIGHbetween 1.0 and 2.35 V
or higher than 4.3 V
6.4.2R
ECORD-MUTE MODE
SELECTION OF
HEAD SIGNAL
pin PBIN2
(head 2)
pin PBIN1
(head 1)
The record-mute mode is selected by setting bit AFM = 1
and either setting bits DOC, SHH and DETH to logic 0 or
switching the RM control signal to HIGH-level.
During the record-mute mode no recording current is
present on pin RECOUT (see Fig.6). The head amplifier
status actually equals the playback mode, however, the
second amplifier stage is disabled to minimize power
consumption.
The RM control signal on pin RMHID enables fast
switching between the record and record-mute modes
(see Table 2). If the I2C-bus control is set to the record
mode, the use of record-mute mode control via pin RM
allows for accurate timing of recording start and stop,
independent of the I2C-bus control (see Section 6.1).
1999 Apr 1410
Philips SemiconductorsProduct specification
Audio processor with head amplifier for VHS hi-fiTDA9605H
Table 2Selection of recording modes
RM
SIGNAL
LEVEL ON
PIN RMHID
RECORD MODE
LOWlower than 2.35 Vrecord or record-mute
mode as defined by
2
I
C-bus control
HIGHhigher than 2.65 V record-mute mode
6.4.3R
ECORD MODE
The record mode is selected by setting bit AFM = 1 and
setting bits DOC, SHH and DETH from logic 001 to 111
and switching the RM control signal to LOW-level.
During the record mode actual recording is activated and
the recording current is output on pin RECOUT
(see Fig.6). Pins PBIN2 and PBIN1 form a connection to
the 5 V head amplifier supply voltage (V
). Pin HMSW
CCH
is internally connected to pin RECOUT and the external
capacitor has no function in this mode.
The desired carrier mix ratio is set via I2C-bus control
bits DOC, SHH and DETH. A wide selection of recording
currents is available to fit different head and head
transformer specifications and are set via bits HAC2,
HAC1, HAC0 and range bit HRL. The setting of the carrier
mix ratio does not change the selected recording current.
The DC bias current on pin RECOUT is changed
proportional to the selected recording current for
optimizing the performance and minimizing the power
consumption for each recording current selected.
A Boucherot damping circuit is connected between
pin HMSW and ground to prevent head current resonance
peaking. A capacitor of 10 nF and a resistor of 470 Ω are
specified in Fig.14, but the component values are not
critical.
6.4.4H
EAD AMPLIFIER POWER SUPPLY AND GROUND
The head amplifier is supplied via a separate 5 V supply
(pin V
) and ground (pin GNDH).
CCH
A capacitor of 100 nF should be placed close to the device
between pins V
and GNDH for proper decoupling of
CCH
the power supply.
The head amplifier ground (pin GNDH) should be
connected to the main ground (pin GND).
handbook, full pagewidth
35
36
37
38
35 kΩ
GNDH
35 kΩ
GNDH
GNDH
TDA9605H
PBIN2
AH2
RECOUT
AH1
PBIN1
HMSW
a. Playback mode and record-mute mode.b. Record mode.
Fig.6 Simplified circuit diagrams of the head amplifier modes.
1999 Apr 1411
AH2
AH1
PBIN2
RECOUT
PBIN1
HMSW
35
36
37
38
V
V
CCH
CCH
5 Ω
GNDH
TDA9605H
MGR841
Philips SemiconductorsProduct specification
Audio processor with head amplifier for VHS hi-fiTDA9605H
6.5Automatic calibration
The integrated auto-calibration system is activated by
means of bit CALS of the power byte (see Fig.7).
The auto-calibration system ensures hi-fi processing is
well in accordance with the VHS hi-fi system standard by
an automated adjustment of carrier frequencies,
band-pass filters and noise reduction filters. Calibration is
only needed after start-up of the video recorder.
The calibration settings remain stable as long as the
supply voltage (VCC) is present.
Auto-calibration is only executed in the record-mute mode
or record mode and no standby mode or test mode should
be selected, i.e. auto-calibration requires the setting of
bit AFM = 1, bit STBP = 0, bit STBA = 0 and bit TEST = 0.
Auto-calibration is started after setting bit CALS = 1.
Calibration is performed fully automatically, using the HID
control signal as a time reference. Audio signals are not
disturbed during the calibration process.
Calibration of the oscillator frequencies is performed by
measuring the number of oscillator cycles within one
period when the HID control signal is at HIGH-level and
comparing this result with an internal value stored in the
Read Only Memory (ROM). Four different ROM values are
available for NTSC or PAL (SECAM) system calibration of
both the left and right channel carrier.
In case of NTSC a special routine is active for the
calibration of the right channel carrier which results in a
frequency difference between the left and right channel
carrier near to 401.2 kHz. This value effectively reduces
the crosstalk from hi-fi carriers to video colour signal as
present during Extended Play (EP) tape speed. NTSC
calibration uses a standard HID control signal of 29.97 Hz
(pulse width =16.683 ms) where PAL calibration uses a
standard HID control signal of 25 Hz (pulse
width = 20 ms). After auto-calibration the maximum
frequency error is ±5 kHz assuming a time error of
maximum of 5 µs when the HID control signal is at
HIGH-level. Jitter on the HID control signal should not
exceed 1 µs to realize EP optimization within ±2 kHz for
NTSC. In general, the crystal based HID control signal
available in the video recorder can be used without
modification.
When the calibration of the oscillators is completed the
band-pass filters are calibrated. The integrated weighting
and FM de-emphasis filters of the noise reduction are
calibrated at the same time.
The total auto-calibration time needed is maximum
17 cycles of the HID control signal. Completion of the
calibration is signalled by bit CALR =1 of the read byte.
The calibration can also be monitored by means of the
envelope output. For this purpose the voltage on
pin ENVOUT is forced to >2.5 V during the calibration.
The audio signal to the audio envelope function (level
meter) should be muted (i.e. output select = mute).
handbook, full pagewidth
2
I
C-bus write bit CALS
RMHD input
left channel oscillator
right channel oscillator
band-pass and
noise reduction filters
2
I
C-bus read bit CALR
ENVOUT output
logic 0
logic 1
Fig.7 Example of automatic calibration flow.
1999 Apr 1412
logic 0
4 V3 V
5 V
logic 1
calibration
ready
MGR842
Philips SemiconductorsProduct specification
Audio processor with head amplifier for VHS hi-fiTDA9605H
Otherwise, the audio envelope output voltage may
become >2.5 V which makes it impossible to detect the
completion of the calibration on pin ENVOUT.
Calibration relies upon the frequency accuracy of the HID
control signal. The calibration result may be incorrect
when the HID control signal is disturbed during a critical
part of the calibration. An additional check is incorporated
to detect such a situation by reading bit CALE during
calibration. When bit CALE = 1, the calibration result is
detected to be unreliable due to external causes. A new
auto-calibration can be started by setting bit CALS = 0
followed by setting bit CALS = 1. Bit CALE always reads
logic 1 when bit CALS is logic 0.
The oscillators and band-pass filters can be switched
between NTSC and PAL system frequencies after a
calibration in NTSC or PAL mode without the need of
additional calibration. Switching between these system
modes is executed immediately and can be done in any
operating mode. The frequency accuracy of system
switching is 100 ±3 kHz for both carriers. To obtain the
best possible frequency accuracy in the record mode it is
good practice to recalibrate after system switching.
6.6Power muting
Switching off and on of the power supply voltage or using
the built-in passive standby mode results in rising and
dropping of the output DC voltages and causes strong
disturbances on the output pins. The TDA9605H includes
three integrated mute switches to block such disturbances
so avoiding the need for an external mute circuit. Pop-free
line and RF converter output signals are realized by
connecting the integrated power mute switches behind the
line and RFC output capacitors.
Power muting is active when bit MUTE = 1 (see Fig.8).
Power muting is automatically activated when V
CC
is
switched on, because this situation is the Power-on reset
default state. The integrated mute switches on
pins MUTEC, MUTEL and MUTER are closed and form a
low-impedance path to ground. Furthermore, the
pins RFCOUT, LINEL and LINER are current limited to
−1 mA to avoid excessive supply currents and to achieve
good noise attenuation without the need for a series
resistor between the output and mute pins. Pins DECL and
DECR are also current limited for using the integrated
power mute switches or for assisting external muting.
handbook, full pagewidth
bit MUTE (I
bit STBP (I
RFCOUT
LINEL
LINER
output signal
with power mute
MUTEC
MUTEL
MUTER
(1) Power-on reset.
V
CC
auto-mute
(V
CC
2
2
C-bus)
< 7 V)
power off
(standby)
(
C-bus)
power
off
1)
(
t
mute
active
operation
t
mute
passive
standby
t
mute
active
operation
t
mute
Fig.8 Examples of power mute control and the auto-mute function.
1)
auto-mute
power
off
MGR843
t
mute
active
operation
1999 Apr 1413
Philips SemiconductorsProduct specification
Audio processor with head amplifier for VHS hi-fiTDA9605H
During power muting the internal output signal is also
muted. After the output DC voltage has been established
power muting can be de-activated by setting bit MUTE = 0.
Now the mute switches are opened resulting in a
high-impedance path of 100 kΩ to ground. The output
current limiting is not active.
Power muting is also used in combination with the
integrated passive standby mode (bit STBP = 1). During
this mode the output circuits are switched off and the line,
decoder and RF converter output voltages decrease to 0 V
using a discharge current of 1 mA. Do not set power mute
mode and change the passive standby mode at the same
time. Power mute mode should be activated first, followed
by switching on or off of the passive standby mode to avoid
possible output glitches.
It should be noted that the time needed for stabilizing the
output DC voltage is proportional to the output capacitor
value. A safe mute time is 200 ms using a 10 µF capacitor
(t
=C×20000 s). Power muting consumes
mute
approximately 4 mA additional supply current, so to obtain
minimum power consumption the mute mode should be
de-activated after use. Very good performance is achieved
for power-up, power-down and passive standby mode
switching.
An auto-mute function is included which activates power
muting when the supply voltage drops below 7 V.
The performance of this auto-mute function depends upon
the power voltage drop rate. The voltage drop rate should
not exceed 1 V during 10 ms. The best performance
independent of voltage drop rate is realized by activating
the passive standby mode before switching off the power
supply voltage (by setting bit MUTE = 1 and bit STBP = 1).
6.7Envelope output
Pin ENVOUT is an analog output for stereo audio level
(e.g. level meter display) and for playback FM carrier level
(e.g. auto-tracking). The functional diagram is given in
Fig.9 and the timing diagram is shown in Fig.10. Only one
ADC input is needed on the microcontroller for reading all
the required information.
During the playback mode the selection between audio
level and carrier level information is realized by setting
2
I
C-bus control bit EOS (see Table 3). The AF envelope
output is defined by the signal selection made at the output
select.
During the record mode bit EOS offers the selection
between the audio level of the output select or the audio
level of the fixed hi-fi stereo signal. This is a helpful setting
when the microcontroller uses the audio level information
to adjust the hi-fi recording level (volume control).
The HF envelope output signal is continuous and is
derived from the left channel carrier. The HF envelope
output exhibits a logarithmic characteristic (see Fig.11).
In a standard application circuit only the left channel carrier
level is required to support auto-tracking or manual
tracking. However, test 10 of the special test mode allows
for the right channel carrier level output instead for
measurement purposes (see Section 14.4).
The AF envelope output as a function of the output level is
given in Fig.12.
The AF envelope circuit uses time multiplexing for the left
and right channel audio level. A peak-hold function and
dynamic range compression (square root function) are
included for easy read out. The peak-hold function and the
left and right channel multiplexing are controlled by the
HID control signal on pin RMHID (see Table 4).
Table 3Selection of the envelope output
MODEBIT AFMBIT EOSENVELOPE OUTPUTFUNCTION
Playback
Record
Table 4AF envelope output with channel multiplexing
HID SIGNALLEVEL ON PIN RMHIDAF ENVELOPE OUTPUT
LOWlower than 0.6 V or between 2.65 and 3.8 Vleft channel audio peak level
HIGHbetween 1.0 and 2.35 V or higher than 4.3 Vright channel audio peak level
1999 Apr 1414
0
1
0AF envelope: via output selectlevel meter display
1HF envelopeauto-tracking or manual tracking display
0AF envelope: via output selectlevel meter display
1AF envelope: hi-fi stereorecord volume control (and level display)
Philips SemiconductorsProduct specification
Audio processor with head amplifier for VHS hi-fiTDA9605H
handbook, full pagewidth
left channel audio:
output select
hi-fi
right channel audio:
output select
hi-fi
EOS • AFM
t
d
FULL-WAVE
RECTIFIER
FULL-WAVE
RECTIFIER
SQUARE ROOT
COMPRESSION
SQUARE ROOT
COMPRESSION
1.3 or 1.4 MHz carrier
1.7 or 1.8 MHz carrier
RESET
PEAK HOLD
RESET
PEAK HOLD
HF LEVEL DETECTOR
HF LEVEL DETECTOR
SAMPLE-
AND-HOLD
SAMPLE-
AND-HOLD
Fig.9 Functional diagram of the envelope output circuit.
SAMPLE
SAMPLE
AF
envelope
HF
envelope
test
10
RM
HID
EOS • AFM
RMHID
ENVOUT
MGR845
handbook, full pagewidth
I2C-bus
registers
HID signal
HID period
ENVOUT
level meter
display
EOS = 1 and
AFM = 0
0123
HF envelope
tracking level
indication
EOS = 0 or AFM = 1
peak right
in period −1
in period 0
peak right
in period 0
peak left
left (period 0)
right (period 0)
Fig.10 Timing diagram of the envelope output signal.
1999 Apr 1415
peak left
in period 1
peak right
in period +1
peak left
in period 2
left (period 1)
right (period 1)
peak right
in period +2
right (period 2)
peak left
in period +3
left (period 2)
MGR844
Philips SemiconductorsProduct specification
Audio processor with head amplifier for VHS hi-fiTDA9605H
handbook, halfpage
5
ENVOUT
output
voltage
4
(V)
3
2
1
0
−1
10
1.3 MHz (NTSC) or 1.4 MHz (PAL) at internal node between head
amplifier and HF AGC.
An AGC function is incorporated to avoid overmodulation
in the RF converter connected to pin RFCOUT. The AGC
limits the maximum signal level on the RF converter output
to −3 dBV (see Fig.13).
−3
line output (dBV)
Fig.13 AGC output of RF converter.
1999 Apr 1416
The RF converter output can be muted by setting
bit RFCM = 1. When using this RF converter mute, the
AGC control is reset by discharging the capacitor
connected to pin RFACG.
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