U4459B
TELEFUNKEN Semiconductors
Rev. A1, 15-Jul-96
1 (7)
IF Amplifier for Cable DVB Processing
Description
The U4459B is an integrated bipolar circuit suitable for
the IF processing in cable-DVB receiver (DVB = Digital
Video Broadcasting) and cable network application.
The circuit contains a wideband IF amplifier, mixer stage,
gain control for the IF amplifier and a tuner-AGC
(Automatic Gain Control) with adjustable take over point
for an additional external preamplifier (tuner).
Features
D Input frequency range 30 to 50 MHz (1st IF)
D Wideband IF amplifier with high linearity
D Gain control of the IF amplifier by external
dc voltage
D Mixer stage with local oscillator input
(symmetrical or unsymmetrical)
D High output level of mixed signal (2nd IF)
(up to 2.4 V, peak-to-peak value)
D Tuner-AGC with adjustable take over point for a
preamplifier
D Supply voltage range 6.8 to 13.5 V
Package: DIP16
1
16
3
IF1 in
8
9
5
13
2
IF1 in
Mixer
IF amp
IF gain
control
Bandgap
V
Tun
V
Gain
4,15
I
Tun
BG
GND
6
14
IF2 out
V
S
95 9636
LO in
LO in
Figure 1. Block diagram
U4459B
TELEFUNKEN Semiconductors
Rev. A1, 15-Jul-96
2 (7)
Pin Description
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
I
tun
GND
95 10696
V
gain
IF2
out
NC
IF1
in
V
tun
VS
BG
NC
NC
NC
LO
in
IF1
in
GND
LO
in
Figure 2.
Pin
Symbol
Function
1
IF1
in
IF1 input
2
V
tun
Take over point of tuner-AGC
3
I
tun
Tuner-AGC output current
4
GND
Ground
5
V
gain
IF gain control input
6
IF2
out
IF2 output
7
NC
Not connected
8
LO
in
Local oscillator input
9
LO
in
Local oscillator input
10
NC
Not connected
11
NC
Not connected
12
NC
Not connected
13
BG
Bandgap reference
(internal use only)
14
VS
Supply voltage
15
GND
Ground
16
IF1
in
IF1 input
Circuit Description
The U4459B consists of a controllable 3-stage wideband
amplifier, a mixer, IF-AGC and a tuner-AGC with
adjustable take over point. The IF1 input voltage is
applied at Pin 1 to 16 and it is fed via a 3-stage gain
controlled wideband amplifier to the mixer. The wide-
band amplifier with high linearity is gain controlled by
external dc voltage. The oscillator voltage (Pin 89) for
the mixer stage can be applied symmetrically as well as
unsymmetrically.
The mixed signal (2nd IF) is fed through a buffer
amplifier to the output Pin 6. The control voltage can also
be used for an additional external preamplifier in the
tuner. This tuner-AGC with adjustable take over point
protects the IF1 input against overload.
Absolute Maximum Ratings
Reference point Pin 4, unless otherwise specified
Parameters
Symbol
Value
Unit
Supply voltage
Pin 14
V
s
13.5
V
Supply current
Pin 14
I
s
55
mA
Power dissipation
V
s
= 13.5 V
Pin 14
P
750
mW
Junction temperature
T
j
+125
C
Storage temperature
T
stg
25 to +125
C
U4459B
TELEFUNKEN Semiconductors
Rev. A1, 15-Jul-96
3 (7)
Operating Range
Parameters
Symbol
Value
Unit
Supply voltage range
Pin 14
V
s
6.8 to 13.5
V
Ambient temperature
T
amb
10 to +80
C
Thermal Resistance
Parameters
Symbol
Value
Unit
Junction ambient when soldered to PCB
R
thJA
60
K/W
Electrical Characteristics
V
s
= +8 V, T
amb
= +25
C; reference point Pin 4, unless otherwise specified
Parameters
Test Conditions / Pins
Symbol
Min.
Typ.
Max.
Unit
DC supply
Pin 14
Supply voltage
V
S
6.8
8.0
13.5
V
Supply current
I
S
45
55
mA
IF1 input, 1st IF
Pin 116
Input sensitivity
(RMS value)
Output voltage 2 V
pp
V
IF1
80
120
V
RMS
IF1 input frequency range *)
f
in
30
50
MHz
Input impedance
R
in
1.2
k
W
Input capacitance
C
in
2
pF
IF gain control input
Pin 5
IF gain control range
Output voltage 2 V
pp
G
v
60
66
dB
Local oscillator input
Pin 89
Input voltage (RMS value)
v
LO
100
mV
RMS
Input frequency range *)
f
LO
30
50
MHz
IF2 output, 2nd IF
Pin 6
DC output voltage
V
5
= 3 V
V
DC
3.1
V
Upper limiting level
V
lim
4.5
V
Lower limiting level
V
lim
1.7
V
IF2 signal bandwidth
( 3 dB) *)
Output voltage 2 V
pp
B
12
MHz
Residual carrier,
fundamental wave
v
res
20
mV
Output current
source
sink
I
out
1.5
5.0
2.5
mA
Tuner-AGC
Available AGC current
I
tun
2.0
4.0
6.0
mA
*)
Not measured during production
U4459B
TELEFUNKEN Semiconductors
Rev. A1, 15-Jul-96
4 (7)
16
15
14
13
1
2
3
4
U4459B
12
11
10
5
6
7
9
8
10 nF
10
mF
22
mH
4.7
mF
+V
S
200
W
10 nF
2:1
LO
input
Tuner AGC
IF2 out
IF gain
control
Tuner AGC
take over
10 k
W
10 nF
1:2
200
W
IF1
input
95 9637
10 nF
10 nF
*)
*) depends on application
1
mF to 10 mF
95 9637
Figure 3. Test circuit
16
15
14
13
1
2
3
4
U4459B
12
11
10
5
6
7
9
8
10 nF
10
mF
22
mH
+V
S
200
W
10 nF
2:1
LO
input
Tuner AGC
IF2 out
IF gain
control
Tuner AGC
take over
10 k
W
95 9638
SAW filter
IF1
in
10 nF
10 nF
*)
*) depends on application
1
mF to 10 mF
Figure 4. Basic application circuit
U4459B
TELEFUNKEN Semiconductors
Rev. A1, 15-Jul-96
5 (7)
Internal Pin Configuration
1.2 k
W
1.2 k
W
1
16
3 k
W
3 k
W
94 9227
Figure 5. IF1 input
8
5.6 k
W
94 9243
5.6 k
W
9
Figure 6. Local oscillator input
94 9242
6
Figure 7. IF2 output
94 9230
50
W
5
Figure 8. IF gain control input
2
94 9228
3 k
W
2 k
W
Figure 9. Tuner-AGC take over point
3
94 9229
Figure 10. Tuner-AGC output
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