TEF6721HL/V1 NXP Semiconductors, TEF6721HL/V1 Datasheet - Page 11

• Manufacturer Part Number: TEF6721HL/V1
• Description: Tuners DIGITAL IF TUNER IC
• Manufacturer: NXP Semiconductors

Specifications of TEF6721HL/V1

• Bus Type: I2C
• Maximum Frequency: 9.99 MHz, 108 MHz
• Minimum Frequency: 5.73 MHz, 64 MHz
• Modulation Technique: AM, FM
• Mounting Style: SMD/SMT
• Package / Case: LQFP-64
• Function: Radio
• Noise Figure: 4.5 dB, 8.5 dB
• Operating Supply Voltage: 8.5 V
• Supply Voltage (min): 8 V
• Supply Voltage (max): 9 V
• Minimum Operating Temperature: - 40 C
• Maximum Operating Temperature: + 85 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: TEF6721HL/V1,557

Philips Semiconductors
7.7
The AGC detects at the FM mixer input and the IF AGC
amplifier input. The AGC threshold for the FM mixer input
is programmable via the I
exceeded, the AGC sources a current to an external
PIN diode circuit, keeping the RF signal level at the FM
mixer input constant.
The keyed function shifts the threshold of the AGC if the
in-band signal is small. This reduces desensitization by
other strong transmitters. The amount of threshold shift is
limited to 10 dB. The keyed function can be activated via
the I
delivered from IF DSP via pin KAGC.
The AGC can be activated via the I
current as a local function for search tuning. In AM mode
the AGC can be activated to source a constant 10 mA
current into the FM PIN diode.
7.8
2003 Oct 21
handbook, halfpage
Car radio tuner front-end for digital IF
8.5 V
2
C-bus and is controlled by in-band level information
22
22
nF
Fig.4 Separate IF paths for AM and FM mode.
FM keyed AGC
AM mixer
MIXER
12
AM
10
I/Q-MIXER
11
FM
TEF6721HL
2
C-bus. When the threshold is
9
7
22
nF
L1
L2
2
6
C-bus to source a fixed
R2
FM IF filter
AGC
IF
R3
5
22
nF
AM IF filter
4
R1
MDB414
3
11
The AM mixer has a high dynamic range and converts
AM RF to an IF frequency of 10.7 MHz.
The outputs of the AM and FM mixers can be separated to
allow the use of different IF filters for AM and FM modes.
Figure 4 shows this optional application. By adding the
resistor R1 between pins AMIFIN and IFAGCBIAS the
input impedance of the IF AGC amplifier is matched to the
AM IF filter output impedance.
The input impedance of the AM IF filter is matched to
330
7.9
The AM wideband AGC in front of the AM mixer is realized
first by a cascoded NPN transistor, which controls the
transconductance of the RF amplifier JFET with 10 dB of
AGC range. Second, an AM PIN diode stage with 30 dB of
AGC range is available. The minimum JFET drain source
voltage is controlled by a DC feedback loop (pin
VAMCASFB) in order to limit the cascode AGC range to
10 dB. If the cascode AGC is not required, a simple
RF AGC loop is possible by using only a PIN diode.
In some conditions, noise behaviour will increase. In this
case pins VAMCAS and VAMCASFB have to be left
open-circuit. In FM mode, the cascode switches off the
JFET bias current to reduce total power consumption.
The AGC detection points for AM RF AGC are at the AM
mixer input (threshold programmable via the I
the AM and FM IF AGC amplifier input (fixed threshold).
In FM mode the AM AGC can be activated via the I
to sink a constant current of 1 mA from the PIN diode.
7.10
This output current can be used to reduce the gain of
active antennas before start of RF AGC.
The output (open-collector) sinks a current which in
AM mode is proportional to the voltage at pin TRFAMAGC
and in FM mode proportional to the RF level detector
voltage (pin TFMAGC) inside the FM AGC.
with R2 and R3.
AM RF AGC
FM/AM RF AGC buffer
Preliminary specification
TEF6721HL
2
C-bus) and
2
C-bus