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STPAC01F1
January 2003 - Ed: 1
Flip-Chip package
Gnd1
RFin
Gnd1
Gnd1
Gnd2
Bias
DC
out
V
Temp
3
2
1
A
B
C
PIN CONFIGURATION (ball side)
s
The use of IPAD technology allows the RF
front-end designer to save PCB area and to
drastically suppress parasitic inductances.
BENEFITS
RF DETECTOR FOR
POWER AMPLIFIER CONTROL
IPAD
TM
The STPAC01F1 has two outputs, one for the
signal
detection
and
another
one
for
the
temperature compensation:
s
V
DCout
= 0.88 V at 0.85 GHz at 10 dBm
s
V
DCout
= 1.07 V at 1.85 GHz at 10 dBm
s
Vsupply = 5 V max.
MAIN PRODUCT CHARACTERISTICS
The STPAC01 is an integrated RF detector for the
power control stage. It converts RF signal coming
from the coupler into a DC signal usable by the
digital stage. It is based on the use of two similar
diodes, one providing the signal detection while
the second one is used to provide a temperature
information to thermal compensation stage. A
biasing stage suppresses the detection diode drop
voltage effect.
Target applications are cellular phones and PDA
using GSM, DCS, PCS, AMPS, TDMA , CDMA
and 800MHz to 1900MHz frequency ranges
DESCRIPTION
TM : IPAD is a trademark of STMicroelectronics.
Coupler
GND2
GND1
V
DCOut
STPAC01F1
RF input
V
BIAS
V
temp
Thermal
compensation
Low pass
filter
RF detector
FUNCTIONAL DIAGRAM
STPAC01F1
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Symbol
Parameter and test conditions
Value
Unit
V
BIAS
Bias voltage
5
V
P
RF
RF power at the RF input
20
dBm
F
OP
Operating frequency range
0.8 to 2
GHz
V
PP
ESD level as per MIL-STD 883E method 3015.7 notice 8 (HBM)
100
V
T
OP
Operating temperature range
-30 to +85
C
T
STG
Storage temperature range
-55 to 150
C
ABSOLUTE RATINGS (Tamb = 25C)
Symbol
Parameter
Test conditions
Min.
Typ.
Max.
Unit
V
BIAS
Operating bias voltage
2.2
3.2
V
I
BIAS
Bias current
V
BIAS
= 3.2 V
0.5
mA
ELECTRICAL CHARACTERISTICS (Tamb = 25C)
PARAMETERS RELATED TO BIAS VOLTAGE
Symbol
Parameter
Test conditions
Min.
Typ.
Max.
Unit
V
Temp
Temperature output
voltage (see fig. 6)
I
DC
= 50A
1.83
1.93
2.03
V
V
Temp
Temperature output
voltage variation
(see fig. 6)
I
DC
= 50A, 0 < T
amb
< 70 C
0.09
V
I
DC
= 50A, 2.2 < V
BIAS
< 3.2 V
0.44
PARAMETERS RELATED TO TEMPERATURE FUNCTION
Symbol
Parameter
Test conditions
Min.
Typ.
Max.
Unit
V
DCout
DC output voltage
(see fig. 1, I
DC
= 50A)
F = 1.85 GHz, P
RF
= 10 dBm
0.97
1.07
1.17
V
F = 1.85 GHz, P
RF
= -20 dBm
1.83
1.93
2.03
F = 0.85 GHz, P
RF
= 10 dBm
0.78
0.88
0.98
F = 0.85 GHz, P
RF
= -20 dBm
1.83
1.93
2.03
V
DCout
DC output voltage variation
(see fig. 5, I
DC
= 50A)
0 < T
amb
< 70C,
F = 1.85 GHz, P
RF
= 10 dBm
0.09
V
2.2 < V
BIAS
< 3.2 V,
F = 1.85 GHz, P
RF
= 10 dBm
0.44
PARAMETERS RELATED TO DETECTION FUNCTION (V
BIAS
= 2.7 V, DC output load = 100 k
)
STPAC01F1
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Coupler
GND2
Out
GND1
V
DCOut
I
DC
= 50A
I
DC
= 50A
STPAC01F1
RF input
V
BIAS
V
temp
Thermal
compensation
Low pass
filter
RF detector
-
+
APPLICATION DIAGRAM
The STPAC01 is the first part of the power amplifier stage and provides both RF power and die
temperature measurements. The above figure gives the basic circuit of RF detector.
A coupler located on the line between RF amplifier output and the antenna takes a part of the available
power and applies it to STPAC01 RF input.
The RF detector and the low pass filter provide a DC voltage depending on the input power. Thermal
compensation provides a DC voltage depending on the ambient temperature. As the detection system and
the thermal compensation are based on the same topology, VDCout will have the same temperature
variation as Vtemp. Connected to a differential amplifier, the output will be a voltage directly linked to the
RF input power. VDCout and Vtemp must be bias with 50A DC current.
This topology offers the most accurate output value as it is 100% compensated.
V
DCOut
I
DC
RF in
V
BIAS
DC output
voltage
RF generator
Power
supply
Current
generator
STPAC
test board
Multimeter
Fig. 1: V
DCout
measurement circuit.
0.8
1
1.2
1.4
1.6
1.8
2
-20
-15
-10
-5
0
5
10
Pin (dBm)
VDCout
850MHz
1850MHz
Tamb = 25C
Ibias = 50A
Vbias = 2.7V
Fig. 2: V
DCout
versus RF input power.
STPAC01F1
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0.9
0.95
1
1.05
800
825
850
875
900
Frequency in MHz
V
DCout
(Freq.) / V
DCOut
(850MHz)
Fig. 3: Relative variation of V
DCout
versus
frequency (from 800 to 900 MHz).
V
DCout
(Freq.) / V
DCOut
(850MHz)
0.9
0.95
1
1.05
1800
1825
1850
1875
1900
Frequency in MHz
Fig. 4: Relative variation of V
DCout
versus
frequency (from 1800 to 1900 MHz).
V
DCOut
I
DC
RF in
V
BIAS
DC output
voltage
RF generator
Power
supply
Current
generator
STPAC
test board
Multimeter
Climatic
chamber
Fig. 5: Temperature effect measurement circuit on
V
DCout
.
V
temp
I
DC
V
BIAS
Temp.
voltage
Power
supply
Current
generator
STPAC
test board
Multimeter
Climatic
chamber
Fig. 6: V
temp
measurement circuit.
1.88
1.9
1.92
1.94
1.96
1.98
0
10
20
30
40
50
60
70
Tamb (C)
Vtemp
Ibias = 50A
Fig. 7: V
temp
output voltage versus ambient
temperature.
STPAC01F1
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1.57mm 50m
1.57mm 50m
315m 50
500m 50
500m 50
650m 65
PACKAGE MECHANICAL DATA
365
365
240
40
220
x
y
x
w
x
w
Dot, ST logo
xxx = marking
yww = datecode
(y = year
ww = week)
All dimensions in m
MARKING
Copper pad Diameter :
250m recommended , 300m max
Solder stencil opening : 330m
Solder mask opening recommendation :
340m min for 300m copper pad diameter
FOOT PRINT RECOMMENDATIONS
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