Datasheet RF2451, RF2451PCBA Datasheet (RF Micro Devices)

NOT FOR NEW DESIGNS

4-247

4

GENERAL PURPOSE

AMPLIFIERS

Product Description

Ordering Information

Typical Applications

Features

Functional Block Diagram

RF Micro Devices, Inc.
7625 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

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RF2

37

1

SiGe HBT

Si CMOS

8

7

6

5

RF IN

GND1

GND2

IPSET

1

2

3

4

RF OUT

ISET

VCC

ENABLE

Bias Circuits

RF2451

3V LOW NOISE AMPLIFIER

• GSM Handsets

• CDMA Handsets

• TDMA Handsets

• IF or RF Buffer Amp lifiers

• Driver Stage for Power Amplifiers

• Oscillator Loop Amplifiers

The RF2451 is a general purpose, low-cost, high perfor­mance low noise amplifier designed for operation from a

2.7V to 4V supply with low current consumption. The
attenuation of the device is controlled when in power
down mode, providing a known gain step. The RF2451 is
available in a small industry-standard MSOP-8 surface
mount package, enabling compact designs which con­serve board space. The design features accurate PTAT
(Proportional To Absolute Temperature) biasing scheme
using band gap cells.

• 700 MHz to 2000MHz Operation

• 2.7V to 3.6V Single Supply

• +5dBm Input IP

3

at 3.0mA

• 12dB Gain at 1950MHz

• 1.8dB Noise Figure at 1950MHz

• 17dB Gain Step

RF2451 3V Low Noise Amplifier
RF2451 PCBA Fully Assembled Evaluation Board

4

Rev A8 000822

.026

.120

.116

10°MAX

0°MIN

.009
.005

.120
.116

.196

.190

1

.016
.010

.036
.032

.006
.002

.027
.017

Package Style: MSOP-8

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RF2451

Rev A8 000822

4

GENERAL PURPOSE

AMPLIFIERS

NOT FOR NEW DESIGNS

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Absolute Maximum Ratings

Parameter Rating Unit

Supply Voltage 4.0 V
Supply Current 20 mA
Operating Ambient Temperature -40 to +85 °C
Storage Temperature -40 to +150 °C

Parameter

Specification

Unit Condition

Min. Typ. Max.

Overall

T=27°C, VCC=2.7V, V

IPSET

=0V,

V

ENABLE

=2.7V

Frequency Range 700 to 2000 MHz

LNA Performance

Freq=1.95 GHz

Gain 10.5 12.5 dB
Noise Figure 1.6 dB
Input IP3 +4.5 +8 dBm At 2.9mA
Input VSWR 5:1 dB (Noise match)
Output VSWR 1.5:1 dB
Off Mode Gain -5.0 dB V

ENABLE

=0V

Gain 17 dB Freq=836MHz
Noise Figure 1.6 dB
Input IP3 0 dBm
Off Mode Gain -8 dB V

ENABLE

=0V

Current Control

Internal current setting “ON” CMOS Low V Voltage on IPSET
External current setting “ON” CMOS High V Voltage on IPSET
Current into ISELECT 1 µAV

ISELECT

=2.7V

Power Control

Power “ON” Voltage CMOS High V Voltage on ENABLE
Power “OFF” Voltage CMOS Low V Voltage on ENABLE
Current into ENABLE 1 µAV

ENABLE

=2.7V

Power Supply

Operating Voltage 2.7 to 3.6 V
Operating Current 2.9 5 mA V

CC

=2.7V, Internal current setting

Leakage Current 1 µAV

ENABLE

=0 V

Caution! ESD sensitive device.

RF Micro Devices believes the furnished information is correct and accurate
at the time of this printi ng. However, RF Micro Devices reserves the ri ght to
make changes to its products without notice. RF Micro Devices does not
assume responsibility for the use of the described product(s).

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RF2451

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GENERAL PURPOSE

AMPLIFIERS

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Pin Function Description Interface Schematic

1RF OUT

RF output pin. Bias for the LNA is provided through this pin, hence it
should be connected to VCC through an inductor.

2 ISET

This pin sets the current for the device. A resistor to ground of 1kΩ pro­vides a current of 17.5mA. The condition for optimal IP3 is to use the
internal current setting option and leave this pin open (no connect).

3VCC

Power supply for the bias circuits.

4 ENABLE

Power down control. This is a CMOS input. When this pin is CMOS
“high” the device is enabled. When the level is CMOS “low” the device
is shut off and a controlled attenuator is turned on.

5 IPSET

This pin selects the internal current setting when CMOS level “low”, and
the external current setting when this pin is CMOS level “high”. The cur­rent is set to 2.8mA using the internal current setting, and can be up to
20mA using the external current setting.

6GND2

Ground connection for the bias circuits.

7GND1

Ground connection for the LNA. Keep traces physically short and con­nect immediately to ground plane for best performance.

8RF IN

RF input pin. This pin is not internally DC blocked and requires an
external blocking capacitor.

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Applicatio n Schematic

1.95GHz

Applicatio n Schematic

836MHz

IPSET

22 nF

RF IN

10 nF

ENABLE

V

CC

1 k

Ω

3.3 nH

1.5 pF

V

CC

RF OUT

8

7

6

5

1

2

3

4

Bias Circuits

IPSET

22 nF

RF IN

82 nH

ENABLE

V

CC

1 k

Ω

18 nH

1 pF

V

CC

RF OUT

8

7

6

5

1

2

3

4

Bias Circuits

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GENERAL PURPOSE

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Evaluation Board Schematic

(Download Bill of Materials from www.rfmd.com.)

IPSET

C1

22 nF

L2

10 nH

ENABLE

V

CC

R1

1 k

Ω

L1

3.3 nH

C2

1.5 pF

V

CC

J2

LNA INPUT

J1

LNA OUTPUT

GND

IPSET

ENABLE

VCC

P1

1
2
3
4

CON4

C5

22 nF

C3

1 nF

C4

1 uF

+

VCC

2.7 V

-

+

VCC

ENVCC

2.6 V

-

+

ENABLE

IPSET

2451400A

8

7

6

5

1

2

3

4

Bias Circuits

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AMPLIFIERS

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Evaluation Board Layout

Board Size 1” x 1”

Board Thickness 0.031”, Board Material FR-4