Preliminary
4
Typical Applications
• GSM Handsets
• CDMA Handsets
• TDMA Handsets
• IF or RF Buffer Amplifiers
RF2371
3V LOW NOISE AMPLIFIER
• Driver Stage for Power Amplifiers
• Oscillator Loop Amplifiers
Product Description
The RF2371 is a general purpose, low-cost, high perfor-
mance 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 RF2371 is
available in a small industry-standard SOT23-8 surface
mount package, enabling compact designs which con-
serve board space. The design features a highly accurate
PTAT (Proportional To Absolute Temperature) biasing
scheme using bandgap cells.
1.59
1.61
0.365
0.15
0.05
4
GENERAL PURPOSE
AMPLIFIERS
0.127
TEXT*
2.80
3.00
0.650
2.60
3.00
*When Pin 1 is in
upper left, text
reads downward
(as shown).
3°MAX
0°MIN
1.44
1.04
0.35
0.55
Optimum Technology Matching® Applied
Package Style: SOT23-8
ü
Si Bi-CMOS
Si BJT
GaAs HBT
SiGe HBT
GaAs MESFET
Si CMOS
Features
• 700MHz 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
RF IN
1
8
7
6
Bias Circuits
5
RF OUT
ISET
VCC
ENABLE
GND1 2
GND2 3
IPSET 4
Ordering Information
RF2371
RF2371 PCBA
3V Low Noise Amplifier
Fully Assembled Evaluation Board
Functional Block Diagram
RF Micro Devices, Inc.
7625 Thorndike Road
Greensboro, NC 27409, USA
Tel (336) 664 1233
Fax (336) 664 0454
http://www.rfmd.com
Rev A2 010205
4-221
RF2371
Absolute Maximum Ratings
Parameter
Supply Voltage
Supply Current
Operating Ambient Temperature
Storage Temperature
Preliminary
Rating
4.0
20
-40 to +85
-40 to +150
Unit
V
mA
°C
°C
Caution!
ESD sensitive device.
RF Micro Devices believes the furnished information 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).
Parameter
Specification
Min.
Typ.
Max.
Unit
Condition
T=27° C, V
CC
=2.7V, V
ISELECT
=0V,
V
ENABLE
=2.7V
4
GENERAL PURPOSE
AMPLIFIERS
Overall
Frequency Range
700 to 2000
10.5
+4
12.5
1.6
+6
-14
5:1
1.5:1
-5.0
17
1.6
0
CMOS Low
CMOS High
1
CMOS High
CMOS Low
1
2.7 to 3.6
2.9
MHz
LNA Performance
Gain
Noise Figure
Input IP3
Input P1dB
Input VSWR
Output VSWR
Off Mode Gain
Gain
Noise Figure
Input IP3
dB
dB
dBm
dBm
dB
dB
dB
dB
dB
dBm
V
V
µA
V
V
µA
V
mA
µA
Freq=1.95GHz
At 2.9mA
(Noise match)
V
ENABLE
=0V
Freq=836MHz
Current Control
Internal Current Setting “ON”
External Current Setting “ON”
Current into ISELECT
Voltage on ISELECT
Voltage on ISELECT
V
ISELECT
=2.7V
Voltage on ENABLE
Voltage on ENABLE
V
ENABLE
=2.7V
Power Control
Power “ON” Voltage
Power “OFF” Voltage
Current into ENABLE
Power Supply
Operating Voltage
Operating Current
Leakage Current
5
1
V
CC
=2.7V, Internal current setting
V
ENABLE
=0V
4-222
Rev A2 010205
Preliminary
Pin
1
2
3
4
5
6
7
8
Function
RF IN
GND1
GND2
IPSET
ENABLE
VCC
ISET
RF OUT
Description
RF input pin. This pin is not internally DC blocked and requires an
external blocking capacitor.
Ground connection for the LNA. Keep traces physically short and con-
nect immediately to ground plane for best performance.
Ground connection for the bias circuits.
This pin selects the internal current setting when CMOS level “low”, and
the external current setting when this pin is CMOS level “high”.
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.
Power supply for the bias circuits.
This pin sets the current for the device.
RF output pin. Bias for the LNA is provided through this pin, hence it
should be connected to VCC through an inductor.
RF2371
Interface Schematic
4
GENERAL PURPOSE
AMPLIFIERS
Rev A2 010205
4-223
RF2371
Application Information
Preliminary
The RF2371 may be configured to use either the internal current setting or the external current setting. This choice is
made by asserting IPSET, pin 4, to CMOS level “low” for the internal current setting or CMOS level “high” for the external
current setting.
Internal Current Setting
When IPSET is set to CMOS “low”, the internal current settings are chosen. This current draw is typically 2.9mA. In this
mode, the resistorR1 may be removed from the evaluation board schematic and ISET left floating. The condition for opti-
mal IP3 is to use the internal current setting option and leave the ISET pin open (no connect).
4
GENERAL PURPOSE
AMPLIFIERS
External Current Setting
The external current setting is configured by using the series resistor between ISET, pin7, and ground (refer to resistor
R1 in evaluation board schematic). The value of the resistor may be changed to permit various operating currents up to a
maximum allowable current of 20mA. The table below gives approximate minimum R1 values to allow the 20mA maxi-
mum current draw at various operating voltages.
Note: When the internal current setting was selected, the part tested drew 4.4mA, which is higher than typical
(2.9mA). Thus values of R1 given vary from part to part.
V
CC
(V)
Resistor R1 (Ω)
Current Draw (mA)
2.7
2.4k
20.1
3.0
2.7k
20.1
3.3
3.0k
20.0
3.6
3.3k
19.8
4-224
Rev A2 010205
Preliminary
Application Schematic
1.95GHz
V
CC
RF2371
22 nF
RF IN
10 nF
1
2
3
Bias Circuits
IPSET
4
5
8
3.3 nH
1.5 pF
RF OUT
1k
Ω
7
V
CC
6
ENABLE
4
GENERAL PURPOSE
AMPLIFIERS
Application Schematic
836MHz
V
CC
22 nF
RF IN
82 nH
1
2
3
Bias Circuits
IPSET
4
5
8
18 nH
1 pF
RF OUT
1k
Ω
7
V
CC
6
ENABLE
Rev A2 010205
4-225
