LX5501A
P
RODUCTION
D
ATA
S
HEET
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 4
Copyright © 2004
Rev. 1.1, 2005-07-14
WWW.Microsemi .COM
InGAP HBT Gain Block
TM
®
APPLICATION NOTE
D
ESIGN
C
ONSIDERATIONS
The gain block is self-biased by the voltage that is present
on pin 5 (V
BIAS
). Chart 1 shows the quiescent current vs. bias
voltage characteristic. Chart 2 shows device characteristics
when operated with a 5v supply and with different values of
external resistor. Using Chart 2 it is possible to trade-off Gain
and P1dB compression point for supply current.
Supply voltages other than 5v may be accommodated by
adjusting the value of the external resistor to produce the
same quiescent current as the 5v case. To calculate the
resistor required for a different supply voltage use the
following formula:
EXT EXT BIAS BIAS
R (V1)=R (5V)• (V1-V ) (5-V )
Where V
BIAS
is the Pin 5 bias voltage obtained from
Chart 1and V1 is the desired supply voltage.
TYPCAL QUIESCENT CURRENT VS. PIN 5
BIAS VOLTAGE @ 25° C
TYPCAL P1DB, GAIN AND IC VS. R
EXT
@ 25° C
0
10
20
30
40
50
60
70
3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9
Pin 5 Bias Voltage - Volts
Icq, Quiescent Current - mA
Ic q
0
2
4
6
8
10
12
14
25 75 125 175
Rext - ohms
Gain, P1dB - dB/dBm
0
5
10
15
20
25
30
35
Ic, Supply Current - mA
Gain
Ic
P1dB
Frequency = 5.8GHz, V
CC
= 5V
TYPCAL S-PARAMETRS @ 25° C TYPCAL 2.4 GHZ CHARACTERISTICS @ 25° C
S21
S11
S12
S22
0
2
4
6
8
10
12
14
16
18
23456
Frequency - GHz
S21 - dB
-30
-25
-20
-15
-10
-5
0
S11, S12, S22 - dB
V
CC
= 5V, R
EXT
= 50Ω
P1dB = 12.0
dBm
-10
-5
0
5
10
15
20
-25 -20 -15 -10 -5 0 5
Pin - dBm
Pout, Gain - dBm/dB
0
5
10
15
20
25
30
35
40
45
50
Ic, Supply Current - mA
P1dB
Pout
Gain
Ic
V
CC
= 5V, R
EXT
= 50Ω
A
A
P
P
P
P
L
L
I
I
C
C
A
A
T
T
I
I
O
O
N
N
S
S
