Datasheet RF2681, RF2681PCBA Datasheet (RF Micro Devices)

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 [phone]

Fax [phone]

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

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).

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.

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

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

Preliminary

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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

Preliminary

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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

Preliminary

4-50

RF2681

Rev A1 010824

4

GENERAL PURPOSE

AMPLIFIERS