Philips Semiconductors
Product specification
2 GHz image rejecting front-end
FEATURES
•
Low-noise, wide dynamic range amplifier
•
Very low noise figure
•
Dual balanced mixer for over 25 dB on-chip image
rejection
•
IF I/Q combiner at 188 MHz
•
On-chip quadrature network
•
Down-conversion mixer for closed-loop transmitters
•
Independent TX/RX fast ON/OFF power-down modes
•
Very small outline packaging
•
Very small application (no image filter).
APPLICATIONS
•
1800 MHz front-end for DCS1800 hand-portable
equipment
•
Compact digital mobile communication equipment
•
TDMA receivers e.g. PCS and RF-LANS.
GENERAL DESCRIPTION
UAA2077BM contains both a receiver front-end and a high
frequency transmit mixer intended to be used in mobile
telephones. Designed in an advanced BiCMOS process it
combines high performance with low power consumption
and a high degree of integration, thus reducing external
component costs and total front-end size.
The main advantage of the UAA2077BM is its ability to
provide over 25 dB of image rejection. Consequently, the
image filter between the LNA and the mixer is suppressed.
QUICK REFERENCE DATA
SYMBOL
V
CC
I
CC(RX)
I
CC(TX)
I
CC(PD)
T
amb
supply voltage
receive supply current
transmit supply current
supply current in power-down
operating ambient temperature
PARAMETER
MIN.
3.6
21.5
10.5
−
−30
4.0
26.5
13.5
−
+25
TYP.
UAA2077BM
Image rejection is achieved in the internal architecture by
two RF mixers in quadrature and two all-pass filters in
I and Q IF channels that phase shift the IF by 45° and 135°
respectively. The two phase shifted IFs are recombined
and buffered to furnish the IF output signal.
For instance, signals presented at the RF input at the
LO + IF frequency are rejected through this signal
processing while signals at the LO
−
IF frequency can form
the IF signal. An internal switch enables the upper or lower
image frequency to be rejected.
The receiver section consists of a low-noise amplifier that
drives a quadrature mixer pair. The IF amplifier has
on-chip 45° and 135° phase shifting and a combining
network for image rejection. The IF driver has differential
open-collector type outputs.
The LO part consists of an internal all-pass type phase
shifter to provide quadrature LO signals to the receive
mixers. The centre frequency of the phase shifter is
adjustable for maximum image rejection in a given band.
The all-pass filters outputs are buffered before being fed to
the receive mixers.
The transmit section consists of a low-noise amplifier and
a down-conversion mixer. In the transmit mode an internal
LO buffer is used to drive the transmit IF down-conversion
mixer.
All RF and IF inputs or outputs are balanced.
Pins RXON, TXON and SXON enable a selection to be
made of whether to reject the upper or lower image
frequency and control of the different power-down modes.
Special care has been taken for fast power-up switching.
MAX.
5.3
33.5
18
50
+85
V
UNIT
mA
mA
µA
°C
ORDERING INFORMATION
TYPE
NUMBER
UAA2077BM
PACKAGE
NAME
SSOP20
DESCRIPTION
plastic shrink small outline package; 20 leads; body width 4.4 mm
VERSION
SOT266-1
1995 Dec 13
2
Philips Semiconductors
Product specification
2 GHz image rejecting front-end
PINNING
SYMBOL
TXINA
TXINB
V
CCLNA
n.c.
RFINA
RFINB
n.c.
LNAGND
SXON
V
QUADLO
TXON
RXON
LOINB
LOINA
V
CCLO
LOGND
IFA
IFB
TXOA
TXOB
PIN
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
DESCRIPTION
transmit mixer input A (balanced)
transmit mixer input B (balanced)
supply voltage for LNA, IF parts
and TX mixer
not connected
RF input A (balanced)
RF input B (balanced)
not connected
ground for LNA, IF parts and TX
mixer
SX mode enable (see Table 1)
input voltage for LO quadrature
trimming
TX mode enable (see Table 1)
RX mode enable (see Table 1)
LO input B (balanced)
LO input A (balanced)
supply voltage for LO parts
ground for LO parts
IF output A (balanced)
IF output B (balanced)
transmit mixer IF output A
(balanced)
transmit mixer IF output B
(balanced)
handbook, halfpage
UAA2077BM
TXINA
TXINB
VCCLNA
n.c.
RFINA
RFINB
n.c.
LNAGND
SXON
1
2
3
4
5
20 TXOB
19 TXOA
18 IFB
17 IFA
16 LOGND
UAA2077BM
6
7
8
9
15 VCCLO
14 LOINA
13 LOINB
12 RXON
11 TXON
MGD155
VQUADLO 10
Fig.2 Pin configuration.
1995 Dec 13
4
Philips Semiconductors
Product specification
2 GHz image rejecting front-end
FUNCTIONAL DESCRIPTION
Receive section
The circuit contains a low-noise amplifier followed by two
high dynamic range mixers. These mixers are of the
Gilbert-cell type, the whole internal architecture is fully
differential.
The local oscillator, shifted in phase to 45° and 135°,
mixes the amplified RF to create I and Q channels.
The two I and Q channels are buffered, phase shifted by
45° and 135° respectively, amplified and recombined
internally to realize the image rejection.
Balanced signal interfaces are used for minimizing
crosstalk due to package parasitics.
UAA2077BM
The IF output is differential and of the open-collector type.
Typical application will load the output with a differential
1 kΩ load; for example, a 1 kΩ resistor load at each IF
output, plus a differential 2 kΩ load consisting of the input
impedance of the IF filter or the input impedance of the
matching network for the IF filter. The power gain refers to
the available power on this 2 kΩ load. The path to V
CC
for
the DC current should be achieved via tuning inductors.
The output voltage is limited to V
CC
+ 3V
be
or 3 diode
forward voltage drops.
Fast switching, ON/OFF, of the receive section is
controlled by the hardware input RXON.
handbook, full pagewidth
VCCLNA
MIXER
IF
amplifier
+45
o
IFA
RFINA
RFINB
LNA
LNAGND
IF
amplifier
+135
o
MGD157
MIXER
IF
COMBINER
IFB
LOIN
RXON
Fig.3 Block diagram, receive section.
1995 Dec 13
5
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