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1997 Apr 03
5
Philips Semiconductors
Preliminary specification
DCS/PCS 2 W power amplifier
CGY2021G
FUNCTIONAL DESCRIPTION
Operating conditions
The CGY2021G is designed to meet the European
Telecommunications Standards Institute (ETSI) DCS
documents, the ETS 300 577 specification, which are
defined as follows:
t
on
= 542.8
μ
s
T = 4.3 ms
Duty cycle = 1/8.
This amplifier is specifically designed for pulse operation
allowing the use of a LQFP48 plastic package.
Power amplifier
The Power Amplifier (PA) consists of four cascaded gain
stages with an open-drain configuration. Each drain has to
be loaded externally by an adequate reactive circuit which
also has to be a DC path to the supply.
The amplifier bias is set by using a negative voltage
applied at pins V
GG1
and V
GG2
. This negative voltage must
be present before the supply voltage is applied to the
drains to avoid current overstress of the amplifier.
Power sensor driver
The power sensor driver is a buffer amplifier that delivers
an output signal at the DETO pin which is proportional to
the amplifier power. This signal can be detected by
external diodes for power control purpose. As the sensor
signal is taken from the input of the last stage of the PA,
it is isolated from disturbances at the output by the reverse
isolation of the PA output stage. An impedance mismatch
at the PA output therefore does not significantly influence
the signal delivered by the power sensor as this normally
occurs when power sense is made using a directional
coupler. Consequently, the cost and space of using a
directional coupler are saved.
LIMITING VALUES
In accordance with the Absolute Maximum Rating System (IEC 134); general operating conditions applied.
THERMAL CHARACTERISTICS
General operating conditions applied.
Note
1.
This thermal resistance is a typical value and is measured under DCS/PCS pulse conditions.
SYMBOL
PARAMETER
MIN.
MAX.
UNIT
V
DD
V
GG
T
j(max)
T
stg
P
tot
positive supply voltage
negative supply voltage
maximum operating junction temperature
IC storage temperature
total power dissipation
7
10
150
150
1.3
V
V
°
C
°
C
W
SYMBOL
PARAMETER
VALUE
UNIT
R
th j-c
thermal resistance from junction to case; note 1
45
K/W