Page 1
ü
4-43
4
GENERAL PURPOSE
AMPLIFIERS
Preliminary
Product Description
Ordering Information
Typical Applications
Features
Functional Block Diagram
RF Micro Devices, Inc.
7628 Thorndike Road
Greensboro, NC 27409, USA
Tel (336) 664 1233
Fax (336) 664 0454
http://www.rfmd.com
Optimum Technology Matching® Applied
Si BJT GaAs MESFETGaAs HBT
Si Bi-CMOS
SiGe HBT
Si CMOS
RF OUT
NC
GC
VCC1
VCC2
VREG
RF IN
NC
PD
GND
GND
GND
101112
1
3
2
654
9
8
7
RF2681
W-CDMA LINEAR VARIABLE GAIN
DRIVER AMPLIFIER
• PA Driver Amplifier for W-CDMA Handsets • General Purpose Driver Amplifier
The RF2681 is a linear variable gain amplifier specifically
designed for PA driver applications in W-CDMA handsets.
The device maintains excellent linearity over a 30 dB gain
control range, while providing a maximum of 26dB gain.
The IC is manufactured on an advanced Gallium Arsenide Heterojunction Bipolar Transistor Process and is
provided in an extremely small 3mmx3mm, 12-pin, leadless chip carrier.
• 30dB Linear Gain Control Range
•26dBMaximumGain
• Single 2.7V to 3.3V Supply
• High Linearity Over Entire Gain Control
Range
• 9dBm Output Drive Available
RF2681 W-CDMA Linear Variable Gain Driver Amplifier
RF2681 PCBA Fully Assembled EvaluationBoard
4
Rev A1 010824
Dimensions in mm.
12°
max
1.00
0.85
3.00
sq.
1.25
0.95
sq.
2
0.30
0.18
0.50
0.23
0.13
4PLCS
0.80
0.65
NOTES:
Shaded Pin is Lead 1.
1
Dimension applies to plated terminal and ismeasured between 0.02 mm and
0.25 m m from terminal end.
2
5 Die thickness allowable: 0.305 m m max.
Package Warpage: 0.05 mm max.
4
Pin 1 identifier must exist on top surfaceof package by identification mark or
feature on the package body. Exact shape andsizeis optional.
3
0.65
0.30
4PLCS
0.60
0.24 typ
0.75
0.50
0.05
0.01
Package Style: LCC, 12-Pin, 3x3
Page 2
Preliminary
4-44
RF2681
Rev A1 010824
4
GENERAL PURPOSE
AMPLIFIERS
Absolute Maximum Ratings
Parameter Rating Unit
Supply Voltage -0.5 to +3.6 V
DC
Operating Ambient Temperature -40 to +85 °C
Storage Temperature -40 to +150 °C
Parameter
Specification
Unit Condition
Min. Typ. Max.
Overall
Usable Frequency Range 1800 to 2100 MHz
Linear Gain Control Range 30 dB
Gain Control Slope 40 dB/V
W-CDMA
Operating Frequency 1920 to 1980 MHz
Small Signal Gain 24 26 29 dB V
GC
=2.4V (Maximum Gain)
-7 -5 -3 V
GC
=0V (Minimum Gain)
Output IP3 +22.0 +24.0 +26.0 dBm V
GC
=2.4V (Maximum Gain)
Noise Figure 3 dB Small signal
Input VSWR 1.4:1 2:1 Over entire gain control range
Output VSWR 1.8:1 2:1
Maximum Linear Output Power 8 9 dBm W-CDMA ACPR<-43dBc
ACPR1 (5MHz Offset) -48 dBc Over entire gain contro l range. P
IN
such that
P
OUT
=9dBm at maximumgain setting.
W-CDMA reverse link m odulation.
ACPR2 (10MHz Offset) -62 dBc
Power Supply
Supply Voltage 2.7 3.3 V Operating range
Gain Control Voltage 0 to 2.4 V Useful range
Supply Current 38 mA V
CC
=2.7V
V
GC
Current 220 µAVGC=2.4V (Maximum Gain)
1.7 mA V
GC
=0.2V
Caution! ESD sensit ive device.
RF Micro Devices believesthe furnishedinformation is correct and accurate
at the time of this printing. However, RF Micro Devices reserves the right to
make changes to its products without notice. RF Micro Devices does not
assume responsibility for the use of the described product(s).
Page 3
Preliminary
4-45
RF2681
Rev A1 010824
4
GENERAL PURPOSE
AMPLIFIERS
Pin Function Description Interface Schematic
1VCC1
DC supply for internal bias circuitry.This pin should be tied to VCC, and
must be bypassed with an RF capac itor. The trace length between the
pin and the bypass capacitor should be minimized. The ground side of
the capacitor should connect immediately to the ground plane.
2VREG
DC supply for internal bias circuitry. This pin should be tied to a 2.7V
supply for proper operation. Increasing this voltage above 2.7V will
result in increased current drain and is not recommended.
3VCC2
Same as pin 1.
4PD
Powerdown pin. This pin should be brought below 1V for proper operation. The device is turned off when the voltage on this pin increases
above 2V.
5NC
This pin is not internally connected, but should be grounded, if possible, to improve RF isolation. Please refer to the evaluation board layout.
6RFIN
RF input pin. This pin requires external matching components, and is
DC-coupled. Please refer to the applications schematic for recommended matching components.
7GND
Ground
8GND
Ground
9GND
Ground
10 RF OUT
RF output pin. This pin requires an external matching network. VCC is
provided through an inductor of that network. Please refer to the applications schematic for recommended matching components.
11 NC
Same as pin 5.
12 GC
Gain control pin. This pin allows the gain of the amplifier to be varied in
a continuous “analog” fashion. With an applied voltage of 0.2V or less,
the amplifier exhibits the minimum gain. In the region between 0.2V
and 2.25V, the amplifier g ain in dB depends on the voltage in a roughly
linear manner. Above 2.25V, the amplifier gain is set for maximum.
Pkg
Gnd
GND
Ground connection for the device “die fla g ”. The backside of the package should be soldered to a top side ground pad which is connected to
the PC board ground plane through multiple vias.
Page 4
Preliminary
4-46
RF2681
Rev A1 010824
4
GENERAL PURPOSE
AMPLIFIERS
Applicatio n Schematic
W-CDMA
101112
1
3
2
654
9
8
7
47 nF
VREG
47 nF
1nF
47 nF
VENABLE
3.6 nH
3pF
2nH
3pF
10 nH
47 nF
VGC
47 nF
OUT
IN
V
CC
V
CC
V
CC
51 Ω
2.2 nH
Page 5
Preliminary
4-47
RF2681
Rev A1 010824
4
GENERAL PURPOSE
AMPLIFIERS
Evaluation Board Schematic
(Download Bill of Materials from www.rfmd.com.)
101112
1
3
2
654
9
8
7
VCC
C2
47 nF
VREG
C3
47 nF
C4
1nF
VCC
C5
47 nF
VENABLE
L1
3.6 nH
C6
3pF
50 Ωµstrip
J1
RF IN
L3
2nH
C9
3pF
L2
10 nH
C8
47 nF
VCC
VGC
C1
47 nF
J2
OUT
50 Ωµstrip
R1
51 Ω
L4
2.2 nH
P1
1
2
3
CON3
GND
P1-1 VCC
C10
1uF
+
GND
P2
1
2
3
4
CON4
GND
P2-2 VCC ZLO
P2-1 VGC
P2-4 VCC
C11
1uF
+
C12
1uF
+
P3
1
2
3
CON3
GND
C13
1uF
+
C14
1uF
+
P3-1 VCC ZHI
P3-3 VENABLE
Page 6
Preliminary
4-48
RF2681
Rev A1 010824
4
GENERAL PURPOSE
AMPLIFIERS
Evaluation Board Layout
Board Size 2.0” x 2.0”
Board Thickness 0.031”, Board Material FR-4
Page 7
Preliminary
4-49
RF2681
Rev A1 010824
4
GENERAL PURPOSE
AMPLIFIERS
Input SWR versus V
GC
1.20
1.25
1.30
1.35
1.40
1.45
1.50
0.00 0.50 1.00 1.50 2.00 2. 50
VGC(V)
SWR
SWR, -40º
SWR, 25º
SWR, 85º
Output SWR versus V
GC
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2.0
0.0 0.5 1.0 1.5 2.0 2.5
VGC(V)
SWR
SWR,-40º
SWR,25º
SWR,85º
Gain versus V
GC
VCC= 2.7 V,Freq = 1950 MHz
-10.0
-5.0
0.0
5.0
10.0
15.0
20.0
25.0
30.0
0.0 0.5 1.0 1.5 2.0 2.5
VGC(V)
Gain (dB)
Gain, -40º
Gain, 25º
Gain, 85º
ACPR versus V
GC
MaximumOutputPower: VCC= 2.7 V,Freq = 1950 MHz
-70.0
-66.0
-62.0
-58.0
-54.0
-50.0
-46.0
-42.0
-38.0
-34.0
-30.0
0.0 0.5 1.0 1.5 2.0 2.5
VGC(V)
ACPR (dBc)
ACPR, -40º
ACPR, 25º
ACPR, 85º
OIP3 versus V
GC
MaximumOutputPower: VCC= 2.7 V,Freq = 1950 MHz
-5.0
0.0
5.0
10.0
15.0
20.0
25.0
30.0
0.0 0.5 1.0 1.5 2.0 2.5
VGC(V)
OIP3 (dBm)
OIP3,-40º
OIP3,25º
OIP3,85º
ICCversus V
GC
VCC= 2.7 V,Freq = 1950 MHz
35.0
36.0
37.0
38.0
39.0
40.0
0.0 0.5 1.0 1.5 2.0 2.5
VGC(V)
I
CC
(mA)
Icc, -40º
Icc, 25º
Icc, 85º
Page 8
Preliminary
4-50
RF2681
Rev A1 010824
4
GENERAL PURPOSE
AMPLIFIERS
Loading...