TELEFUNKEN Semiconductors
U2794B
1000 MHz Quadrature Demodulator
Description
U2794B silicon monolithic integrated circuit is a quadra-
ture demodulator that is manufactured using
TELEFUNKEN’s advanced UHF technology. This
demodulator features a frequency range from
70 – 1000 MHz, low current consumption, selectable
gain, power down mode and is adjustment free. The IC is
suitable for direct conversion and image rejection
applications in digital radio systems up to 1 GHz such as
cellular radio, cordless telephone, cable TV and satellite
TV systems.
Features
D
Supply voltage 5 V (typ.)
D
Very low power consumption 125 mW (typ.)
D
Very good image rejection by means of phase control
loop for precise 90° phase shifting
D
Low LO input level –10 dBm (typ.)
D
LO – frequency from 70 MHz to 1 GHz
D
Power down mode
D
25 dB gain control
D
Very low I/Q output dc offset voltage typ. < 5 mV
D
Duty cycle regeneration for single ended LO input
signal
Block Diagram
V
S
5,6
Power
down
PD
14
IIX
4
II
3
1 IX
OUTPUT
2 I
7
RFin
8
90°Control
loop
0°
90°
Frequency
doubler
Duty cycle
regenerator
15
17 LO
13 PC
12 PCX
Q
19
OUTPUT
20 QX
11
GC
16,18
GND
10
QQX
9
QQ
95 9778
Ordering Information
Extended Type Number
U2794B-AFS
U2794B-AFSG3
Package
SSO 20
SSO 20
Remarks
Rail, MOQ 830 pcs.
Tape and reel, MOQ 4000 pcs.
Rev. A3: 23.08.1995
1 (11)
U2794B
Pin Description
IX
I
II
IIX
V
S
V
S
RF
in
RFX
in
QQ
QQX
1
2
3
4
5
6
7
8
9
10
95 10711
TELEFUNKEN Semiconductors
20 QX
19 Q
18
17
GND
LO
in
16 GND
15 LOX
in
14 PD
13
PC
12 PCX
11 GC
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Symbol
IX
I
II
IIX
V
S
V
S
RF
in
RFX
in
QQ
QQX
GC
PCX
PC
PD
LOX
in
GND
LO
in
GND
Q
QX
Function
IX output
I output
II low pass filter I
IIX low pass filter I
Supply voltage
Supply voltage
RF input
RFX input
QQ low pass filter Q
QQX low pass filter Q
GC gain control
PCX phase control
PC phase control
PD power down
LOX input
Ground
LO input
Ground
Q output
QX output
Electrostatic sensitive device, observe precautions for handling!
Absolute Maximum Ratings
Supply voltage
Input voltage
Junction temperature
Storage temperature range
Parameters
Pins 5 and 6
Pins 7, 8 and 17
Symbol
V
S
V
i
T
j
T
stg
Value
6
0 to V
S
125
–40 to 125
Unit
V
V
°C
°C
Operating Range
Parameters
Supply voltage range
Pins 5 and 6
Ambient temperature range
Symbol
V
S
T
amb
Value
4.75 to 5.25
–40 to 85
Unit
V
°C
Thermal Resistance
Junction ambient
Parameters
SSO 20
Symbol
R
thJA
Value
140
Unit
K/W
2 (11)
Rev. A3: 23.08.1995
TELEFUNKEN Semiconductors
U2794B
Electrical Characteristics
Test conditions (unless otherwise specified); V
S
= 5 V, T
amb
= 25°C, referred to test circuit
System impedance Z
O
= 50
W
, fiLO = 950 MHz, PiLO = –10 dBm
Parameters
Supply voltage range
Supply current
Power down mode, PD
“OFF”mode supply
current
Switch voltage
“Power ON”
“Power DOWN”
LO input, LO
in
Frequency range
Input level
Input impedance
Voltage standing wave
ratio
Duty cycle range
RF input, RF
in
Noise figure (DSB)
symmetrical output
Frequency range
–1 dB input
compression point
Second order IIP
Third order IIP
Test Conditions / Pins
Pins 5 and 6
Pins 5 and 6
V
PD
≤
0.5 V
V
PD
= 1.0 V
Note 1
Pins 5 and 6
Pin 14
Pin 14
VPON
VPOFF
Pin 17
Note 2
See figure 6
See figure 2
fiLO
PiLO
ZiLO
VSWRLO
LODCR
@ 950 MHz Note 3
@ 100 MHz
Pins 7 and 8
Pins 7 and 8
Pins 7 and 8
High gain
Low gain
Note 4
High gain
Low gain
LO leakage
Pins 7 and 8
Symmetric input
Asymmetric input
Pins 7 and 8
see figure 6
NF
70
–12
–10
50
1.2
0.4
12
10
>fiLO
–8
+3.5
35
+3
+13
≤
–60
≤
–55
500
W
ø
0.8pF
dBm
dBm
dBm
1000
–5
MHz
dBm
4
1
V
V
Symbol
V
S
I
S
IsPD
Min.
4.75
Typ.
30
≤
1
20
Max.
5.25
Unit
V
mA
mA
W
2
0.6
dB
fiRF
ICPHG
ICPLG
IIP2HG
IIP3HG
IIP3LG
LOL
Pins 7 and 8
Pins 7 and 8
dBm
Input impedance
ZiRF
Note 1: During power down status a load circuitry with dc-isolation to GND is assumed otherwise a current of
I (V
S
–0.8 V) /RI has to be added to the above power down current for each output I, IX, Q, QX.
Note 2: The required LO-Level is a function of the LO-frequency (see figure 3).
Note 3: Measured with input matching. For 950 MHz the optional transmission line T3 at the RF input may be used
for this purpose. Noise figure measurements without using the differential output signal result in a worse noise
figure.
Note 4: Using Pins 7 and 8 as a symmetric RF input, the second order IIP can be improved.
Rev. A3: 23.08.1995
3 (11)
U2794B
Electrical Characteristics
TELEFUNKEN Semiconductors
Test conditions (unless otherwise specified); V
S
= 5 V, T
amb
= 25°C, referred to test circuit
System impedance Z
O
= 50
W
, fiLO = 950 MHz, PiLO = –10 dBm
Parameters
I/O outputs
Test Conditions / Pins
Emitter follower
I = 0.6 mA
Note 5
Pins 1, 2, 19 and 20
Symbol
I, IX / Q,
QX
BWI/Q
AII/Q
QEI/Q
Max I/Q
VOUT
VOFSI/Q
I/IX
Q/QX
Zout
Min.
Typ.
Max.
Unit
3 dB-bandwidth
w/o external C
I/Q amplitude
Pins 1, 2, 19 and 20
imbalance
I/Q quadrature error
Pins 1, 2, 19 and 20
I/Q maximum output
Pins 1, 2, 19 and 20
swing
Symm. output R
L
> 5 k
W
DC output voltage
Pins 1, 2, 19 and 20
DC output offset voltage Note 6
Pins 1, 2, 19 and 20
Output impedance
Gain control, GC
Control range power
gain, gain high/gain low
Switch voltage
“Gain high”
“Gain low”
Settling time, ST
Power “OFF ” – “ON ”
Power “ON ” – “OFF ”
Pins 1, 2, 19 and 20
see figure 6
Pin 11
Note 7
Pin 11
Pin 11
≥
30
≤ ±0.2
≤ ±1.5
2
2.8
<5
MHz
dB
Deg
V
PP
V
mV
50
W
dB
GCR
PGH/GGL
GCVHigh
GCVLow
STON
STOFF
25
23/–2
1
Note 8
V
V
<4
<4
m
s
m
s
Note 5: Due to test board parasitics this bandwidth is reduced and not equal for I, IX, Q, QX.
If symmetry and full bandwidth is required the lowpass Pins 3, 4 and 9, 10 should be isolated from the board.
The bandwidth of the I/Q outputs can be increased further by using a resistor between the Pins 3, 4, 9 and 10.
This resistors shunt the internal loads of RI 5.4 k
W
The decrease in gain here has to be considered.
Note 6: Output emitter follower internal acurrent I = 0.6 mA allows only small voltage swing with a 50
W
load.
For low signal distortion the load impedance should be RI
≥
5 k
W
Note 7: Referred to the level of the output vector I
2
Q
2
.
Note 8: The low gain status is achieved with an open or high ohmic Pin 11. A recommended application circuit for
switching between high and low gain status is shown in figure 1.
)
4 (11)
Rev. A3: 23.08.1995
TELEFUNKEN Semiconductors
U2794B
95 9842
Test Circuit
1n
*
optional for single ended tests (notice 3 dB bandwidth of AD620)
T1, T2 = transmission line Z
O
= 50
W
.
If no GC function is required, connect pin 11 to GND.
For high and low gain status GC’ is to be switched to GND respectively to V
S
.
Figure 1.
Rev. A3: 23.08.1995
5 (11)
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