1997 Jan 17 3
Philips Semiconductors Product specification
DECT 500 mW power amplifier CGY2030M
PINNING
SYMBOL PIN DESCRIPTION
V
GG2
1 fourth stage negative gate
supply voltage
GND 2 to 4 ground
V
DD2
5 second stage supply voltage
GND 6 and 7 ground
V
DD1
8 first stage supply voltage
RFI 9 PA input
V
GG1
10 first second and third stages
negative gate supply voltage
GND 11 and 12 ground
V
DD3
13 third stage supply voltage
GND 14 and 15 ground
RFO/V
DD4
16 PA output and fourth stage
supply voltage
Fig.2 Pin configuration.
handbook, halfpage
CGY2030M
MBG630
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
GG2
GND
GND
GND
GND
GND
GND
RFO/V
DD4
V
DD3
V
GG1
RFI
GND
GND
GND
V
DD1
V
DD2
FUNCTIONAL DESCRIPTION
Amplifier
The CGY2030M is a 4-stage GaAs MESFET power
amplifier capable of delivering 500 mW (typ.) at 1.9 GHz
into a 50 Ω load. Each amplifier stage has an open-drain
configuration. The drains have to be loaded externally by
adequate reactive circuits which must also provide a DC
path to the supply.
The amplifier can be switched off by means of an external
PNP series switch connected between the battery and the
amplifier drains. This switch can also be used to vary the
actual supply voltage applied to the amplifier and hence,
control the output power.
This device is specifically designed to work with a
maximum duty factor of 25%.
Biasing
Two modes of operation are possible:
• Mode 1
• Mode 2.
MODE 1
In the first mode, the pins V
GG1
and V
GG2
are simply
connected together to the ground via resistors (10 kΩ in
the evaluation board; see Fig.4). The amplifier biases itself
internally to a negative voltage by action of the incoming
RF signal. In this mode, power control cannot be achieved
by varying the amplifier supply voltage; therefore it is
suitable only for applications where power control is not
required such as DECT.
M
ODE 2
If a negative bias is available, a second mode of operation
is possible, in which the amplifier is biased by providing
adequate negative voltages at pins V
GG1
and V
GG2
. In this
mode, the amplifier internal bias does not depend on the
incoming RF level, nor on the drain voltage, so that power
control is possible by variation of the supply voltage.