2004 Fairchild Semiconductor Corporation
June 2004
RMWB04001 Rev. C
RMWB04001
RMWB04001
4 GHz Buffer Amplifier MMIC
General Description
The RMWB04001 is a 2-stage GaAs MMIC amplifier
designed as a 3.5 to 4 GHz Buffer Amplifier for use in point
to point and point to multi-point radios, and various
communications applications. In conjunction with other
amplifiers, multipliers and mixers it forms part of a complete
23 and 26 GHz transmit/receive chipset. The RMWB04001
utilizes our 0.25m power PHEMT process and can be
used in a variety of applications requiring a high gain
medium power amplifier.
Features
4 mil substrate
Small-signal gain 27dB (typ.)
Saturated Power Out 20dBm (typ.)
Voltage Detector Included to Monitor Pout
Chip size 2.4mm x 1.3mm x 100m
Absolute Ratings
Symbol
Parameter
Ratings
Units
Vd
Positive DC Voltage (+4V Typical)
+6
V
Vg
Negative DC Voltage
-2
V
Vdg
Simultaneous (VdVg)
8
V
I
D
Positive DC Current
168
mA
P
IN
RF Input Power (from 50
source)
+7
dBm
T
C
Operating Baseplate Temperature
-30 to +85
C
T
STG
Storage Temperature Range
-55 to +125
C
R
JC
Thermal Resistance (Channel to Backside)
140
C/W
Device
2004 Fairchild Semiconductor Corporation
RMWB04001 Rev. C
RMWB04001
Electrical Characteristics
(At 25C), 50
system, Vd = +4V, Quiescent Current (Idq) = 36mA
Note:
1:
Typical range of gate voltage is -1 to -0.4V to set typical Idq of 36mA.
Functional Block Diagram
1
Note:
1:
Detector delivers > 0.1V DC into 3k
load resistor for > 20dBm output power. If output power level detection is not desired, do not make connection to detector
bond pad.
Parameter
Min
Typ
Max
Units
Frequency Range
3.5
4.0
GHz
Gate Supply Voltage
1
(Vg)
-0.7
V
Gain (Small Signal at Pin = -12dBm)
24
27
dB
Gain Variation vs. Frequency
0.5
dB
Power Output Saturated: (Pin = -2dBm)
18
20
dBm
Input Return Loss (Pin = -12dBm)
14
dB
Output Return Loss (Pin = -12dBm)
12
dB
DC Detector Voltage at Pout = 20dBm
0.5
V
RF IN
RF OUT
GROUND
(Back of Chip)
DRAIN
SUPPLY
Vd1
DRAIN
SUPPLY
Vd2
MMIC CHIP
OUTPUT POWER
DETECTOR VOLTAGE
Vdet
GATE SUPPLY
Vg
2004 Fairchild Semiconductor Corporation
RMWB04001 Rev. C
RMWB04001
Application Information
CAUTION: THIS IS AN ESD SENSITIVE DEVICE.
Chip carrier material should be selected to have GaAs compatible thermal coefficient of expansion and high thermal
conductivity such as copper molybdenum or copper tungsten. The chip carrier should be machined, finished flat, plated with
gold over nickel and should be capable of withstanding 325C for 15 minutes.
Die attachment for power devices should utilize Gold/Tin (80/20) eutectic alloy solder and should avoid hydrogen
environment for PHEMT devices. Note that the backside of the chip is gold plated and is used as RF and DC ground.
These GaAs devices should be handled with care and stored in dry nitrogen environment to prevent contamination of
bonding surfaces. These are ESD sensitive devices and should be handled with appropriate precaution including the use of
wrist grounding straps. All die attach and wire/ribbon bond equipment must be well grounded to prevent static discharges
through the device.
Recommended wire bonding uses 3mils wide and 0.5mil thick gold ribbon with lengths as short as practical allowing for
appropriate stress relief. The RF input and output bonds should be typically 12 mils long corresponding to a typical 2 mil gap
between the chip and the substrate material.
Figure 1. Chip Layout and Bond Pad Locations
Chip Size is 2.40mm x 1.3mm X 100m. Back of chip is RF and DC Ground.
0.00
Dimensions in mm
1.14
0.11
2.28
2.40
0.00
1.19
1.30
0.00
0.57
1.32
2.28
2.40
0.00
0.57
1.19
0.57
0.11
0.11
1.30
2.08
2004 Fairchild Semiconductor Corporation
RMWB04001 Rev. C
RMWB04001
Figure 2. Recommended Application Schematic Circuit Diagram
Figure 3. Recommended Assembly Diagram
MMIC CHIP
RF IN
Gate Supply V
g
Ground
(Back of Chip)
L = Bond Wires
L
L
L
L
L
100 pF
100 pF
10,000
pF
10,000 pF
Drain Supply
V
d
=4 V
100 pF
RF OUT
100 pF
3 k
Output Power
Detector Voltage
V
det
Note:
Detector delivers > 0.1V DC into 3k
load resistor for >20 dBm output power. If output power level
detection is not desired, do not connect to detector bond pad.
L
L
Note: Use 0.003" by 0.0005" Gold Ribbon for bonding. RF input and output bonds should be less than 0.015" long with
stress relief.
RF
Input
RF
Output
5mil Thick
Alumina
50-Ohm
5 mil Thick
Alumina
50-Ohm
2 mil Gap
Die-Attach
80Au/20Sn
Drain Supply
V
d
= 4
Output Power
Detector Voltage
V
det
100pF
100pF
3k
10,000pF
Gate Supply V
g
100pF
10,000pF
L< 0.015"
(2 Places)
100pF
2004 Fairchild Semiconductor Corporation
RMWB04001 Rev. C
RMWB04001
Recommended Procedure for Biasing and Operation
CAUTION: LOSS OF GATE VOLTAGE (Vg) WHILE
DRAIN VOLTAGE (Vd) IS PRESENT MAY DAMAGE THE
AMPLIFIER CHIP.
The following sequence of steps must be followed to
properly test the amplifier:
Step 1:
Turn off RF input power.
Step 2:
Connect the DC supply grounds to the ground of
the chip carrier. Slowly apply negative gate bias
supply voltage of -1.5V to Vg.
Step 3:
Slowly apply positive drain bias supply voltage of
+4V to Vd.
Step 4:
Adjust gate bias voltage to set the quiescent
current of Idq = 36mA.
Step 5:
After the bias condition is established, the RF input
signal may now be applied at the appropriate
frequency band.
Step 6:
Follow turn-off sequence of:
(i) Turn off RF input power,
(ii) Turn down and off drain voltage (Vd),
(iii) Turn down and off gate bias voltage (Vg).
PDF 
ZIP