1995 Dec 13
2
Philips Semiconductors
Product specification
2 GHz image rejecting front-end
UAA2077BM
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.
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.
QUICK REFERENCE DATA
ORDERING INFORMATION
SYMBOL
PARAMETER
MIN.
TYP.
MAX.
UNIT
V
CC
supply voltage
3.6
4.0
5.3
V
I
CC(RX)
receive supply current
21.5
26.5
33.5
mA
I
CC(TX)
transmit supply current
10.5
13.5
18
mA
I
CC(PD)
supply current in power-down
-
-
50
A
T
amb
operating ambient temperature
-
30
+25
+85
C
TYPE
NUMBER
PACKAGE
NAME
DESCRIPTION
VERSION
UAA2077BM
SSOP20
plastic shrink small outline package; 20 leads; body width 4.4 mm
SOT266-1
1995 Dec 13
4
Philips Semiconductors
Product specification
2 GHz image rejecting front-end
UAA2077BM
PINNING
SYMBOL
PIN
DESCRIPTION
TXINA
1
transmit mixer input A (balanced)
TXINB
2
transmit mixer input B (balanced)
V
CCLNA
3
supply voltage for LNA, IF parts
and TX mixer
n.c.
4
not connected
RFINA
5
RF input A (balanced)
RFINB
6
RF input B (balanced)
n.c.
7
not connected
LNAGND
8
ground for LNA, IF parts and TX
mixer
SXON
9
SX mode enable (see Table 1)
V
QUADLO
10
input voltage for LO quadrature
trimming
TXON
11
TX mode enable (see Table 1)
RXON
12
RX mode enable (see Table 1)
LOINB
13
LO input B (balanced)
LOINA
14
LO input A (balanced)
V
CCLO
15
supply voltage for LO parts
LOGND
16
ground for LO parts
IFA
17
IF output A (balanced)
IFB
18
IF output B (balanced)
TXOA
19
transmit mixer IF output A
(balanced)
TXOB
20
transmit mixer IF output B
(balanced)
Fig.2 Pin configuration.
handbook, halfpage
UAA2077BM
MGD155
1
2
3
4
5
6
7
8
9
10
TXINA
TXINB
VCCLNA
VQUADLO
n.c.
RFINA
RFINB
n.c.
LNAGND
SXON
TXOB
TXOA
IFB
TXON
IFA
LOGND
VCCLO
LOINA
LOINB
RXON
20
19
18
17
16
15
14
13
12
11
1995 Dec 13
5
Philips Semiconductors
Product specification
2 GHz image rejecting front-end
UAA2077BM
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.
The IF output is differential and of the open-collector type.
Typical application will load the output with a differential
1 k
load; for example, a 1 k
resistor load at each IF
output, plus a differential 2 k
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 k
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.
Fig.3 Block diagram, receive section.
handbook, full pagewidth
MGD157
LNA
IF
COMBINER
IF
amplifier
IF
amplifier
MIXER
MIXER
RXON
LOIN
IFA
IFB
RFINA
RFINB
LNAGND
VCCLNA
+
45
o
+
135
o
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