1/8
PRELIMINARY DATA
August 2004
STB7720L
2.4-2.5 GHz Silicon Linear Power Amplifier IC
REV. 1
Table 1. Order Codes
Table 2. Absolute Maximum Ratings (Tamb = 25 oC)
Table 3. Thermal Data
Order Codes Marking Package Packaging
STB7720 7720 QFN16L (3x3) Tape & Reel
Symbol Parameter Value Unit
Vcc Supply voltage 5.5 V
Tstb Storage temperature -55 to + 150 oC
TaOperating Ambient Temperature -30 + 85 oC
Pin Input Power 10 dBm
Rth(j-case) Thermal Re sis tance Junc tio n-C as e TBD oC/W
FEATURES SUMMARY
•EXCELLENT LINEARITY EVM 2% @ 19dBm (WITH
802.11g OFDM 54Mb/s MODULATION)
•VERY LOW QUIESCENT CURRENT (60mA)
•INTEGRATED LINEAR ANALOG CONTRO L FOR
DC CURRENT AND OUTPUT MANAGEMENT
•INTEGRATED AVERAGE CHANNEL POWER
DETECTOR
•LEADLESS PACKAGE (3mmx3mm LEAD FREE)
APPLICATIONS
•OPTIMIZED FOR USE IN 802.11 b/g
QFN16L (3x3)
DESCRIPTION
The STB7720L, manufactured in the third generation of ST proprietary pure Si bipolar process, is a
three-stage linear power amplifier (PA) optimized for 802.11b/g wireless LAN (WLAN) applications in the
2.4GHz ISM band. It features 32dB of power gain and delivers 19dBm of linear output power with an EVM
degradation of only 2% under 802.11g Modulation (54Mbps).
The curr ent cons umpti on is as low as 12 5mA a t 19dB m mak e the STB772 0L a g ood s olutio n for mo bile
applications. It achieves less than -40dBc firstside lobe suppression and less than -52dBc secondside
lobe suppression under 802.11b modulation (11Mbps).
The device embeds a Linear Analog Control for DC current and outpu t management an d a Proprietary
Average Channel Power Detec tor solutio n. This power det ector has 20dB dynamic range with 1 voltage
range and ±0.3dB accuracy under 2:1 load mismat ch. It provides a buffered DC voltage propo rtional to
the average channel output power. Thanks to this solution we save cost and space by removing a coupler,
an op amp (usually required in a power down func tion) and also an integrator.
The SBT7720 is housed in QFN 3mmx3mm Leadless package.
Figure 1. Package
STB7720L
2/8
Table 4. Pin Description
PIN Symbol Function
1nc -
2 RFin RF input
3 Vcnt Power Control Voltage
4 Epd Enable Power Detector
5 Vcc Supply Voltage
6 VDET Pow er De tec tor Voltage
7nc -
8nc -
9nc -
10 RFout RF output
11 RFout RF output
12 nc -
13 nc -
14 Vcc Supply Voltage
15 nc -
16 Vcc Supply Voltage
EP GND Ground
Figure 2. Functional Block Diagram
Interstage
Matching
Interstage
Matching
Inpu t pr e
Matching Output
Matching
Bias
Network
Quiescent Current Regulation
IN
Power
Detector
Detected Power
V Supply
OUT
Interstage
Matching
Interstage
Matching
Inpu t pr e
Matching Output
Matching
Bias
Network
Quiescent Current Regulation
IN
Power
Detector
Detected Power
V Supply
OUT
16 15 14 13
12
11
10
9
8765
4
3
2
1
EP (17)
TOP VIEW
Figure 3. Pin Connection
3/8
STB7720L
Table 5. Electrical Characteristics (Tamd = 25 oC, Vcc=3.3V, f=2.45GHz, Vcnt = 2.9V)
Notes:
(1) Parameter measured with RF modula tion based on IEEE 802.11g standard (OFDM 54Mbps)
(2) Parameter measured with RF modula tion based on IEEE 802. 11b standard (CCK 11Mbps)
(3) Load VSWR is set to 10:1 and the angle is varied 360 degrees. Pout = -30 dBm to P1dB
(4) Measured from Device On signal turn on to the point where RF Pout stabilizes to 0.5 dB
Symbol Parame te r Test Co nd itio ns Min. Typ. Max. Unit
f Frequency 2.4 2.45 2.5 GHz
Vcc Supply Voltage 3.0 3.3 3.6 V
Icc(1) Current Consumption Pout = 19 dBm 125 mA
Gp Power Gain 32 dB
P1dB P1dB Compression 25 dBm
Gain variation over
Frequency -/+ 0.5 dB
Gain variation over
Temperature -/+ 0.5 dB
Quiesce nt Cu rre nt 60 mA
EVM(1) Error Vector Magnitude Pout = 19 dBm 2%
ACPR(2) Adiacent Channel
Power Ratio Pout = 19dBm, 1st Side Lobe
Pout = 19dBm, 2nd Side Lobe -40
-52 dBc
dBc
Vdet Output Detector V oltage
Range 1V
Output Detector V oltage
Response Time 4µs
2nd to 5th Harm on ics -40 dBc
Spurious (stability)(3) Load VSWR 10:1 -65 dBc
Turn On Time(4) 0.5 µs
STB7720L
4/8
Figure 4. Supply Current Vs Output Power
0
25
50
75
100
125
150
175
200
225
250
275
0 5 10 15 20 25
Pout (dBm)
Ic (mA)
Tc = +25 °C
TYPICAL PERFORMANCE Figure 5. EVM Vs Output Power
0
1
2
3
4
5
6
7
8
3 5 7 9 11 13 15 17 19 21
Pout (dBm)
EVM (%
)
Figure 6. Power Gain Vs Output Power
20
22
24
26
28
30
32
34
36
38
40
0 5 10 15 20 25 30
Pout (dBm)
Gain (dB)
Tc = -30 °C
Tc =+85 °C
Tc =+25 °C
Temp. depend.
Figure 7. Power Gain Vs Frequency
30
31
32
33
34
2400 2420 2440 2460 2480 2500
f (MHz)
Gain (d B )
Tc = -30 ° C Tc =+25 °C
Tc =+85 °C
Temp. depend.
Figure 8. Power Detector Voltage Vs Pout
400
600
800
1000
1200
1400
1600
0 5 10 15 20 25
Pout (dBm)
Vd
e
t
(
m
V)
Tc = -30 °C
Tc = +85 °C
Tc = +25 °C
Temp. dep en d.
Figu re 9. Power Detector Voltage Vs Pout
400
600
800
1000
1200
1400
1600
0 5 10 15 20 25
Pout (d Bm)
Vdet (mV)
@ 3V, 3.3V, 3.6V
Vcc. depend.
5/8
STB7720L
S1SMA
S2 SMA
RF OUT
C4
10pF
C10
100nF
C12
8pF
RF IN
Vcc (3.3V)
C14 1pF
C9
10pF
C8
100nF
C3
100nF
C11
10pF
C7
1uF
C5
1nF
C6
1nF
R1
10KOhm
C13
1.5pF
C2
1.5p
Vcc (3.3V) Vcc (3.3V)
Vcc (3.3V)
Vcnt (2.9V)
VEpd
λ
/4 @ 3° Harmonic
λ
/4 @ 4° Harmonic
L2
INDUCTOR
NC
1
RFIN
2
Vcnt
3
Epd
4
Vcc
5
Vdet
6
NC
7
NC
8
NC 9
RFout 10
RFout 11
NC 12
NC 13
Vcc 14
NC 15
Vcc 16
L1
ELISA01
TP1
Vcc (3.3V)
+C1
10uF
Vcnt (2.9V)
1
2
3
4
5
Cn1
CON5
VEpd
Figure 10. Circuit Schematic
STB7720L
6/8
Table 6. Mechanical Data - Leadless PACKAGE Exposed Pad (3mm x 3mm)
mm
MIN. TYP. MAX
A 0.80 0.90 1.00
A1 0 0.02 0.05
A3 0.20 REF
b 0.18 0.23 0.30
D3.00 BSC
D2 1.30 1.45 1.55
E3.00 BSC
E2 1.30 1.45 1.55
e0.50 BSC
L 0.30 0.40 0.50
N16
ND 4
NE 4
DIM.
Figure 11. Package Dimensions
PACKAGE MECHANICAL
7/8
STB7720L
REVISION HISTORY
Table 7. Revision History
Date Revision Description of Changes
2 August 2004 1 First Release
STB7720L
8/8
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