MAX2027 Maxim Integrated Products, MAX2027 Datasheet - Page 9

• Manufacturer Part Number: MAX2027
• Description: MAX2027 if Digitally Controlled Variable-gain Amplifier
• Manufacturer: Maxim Integrated Products

Figure 1. Typical Application Circuit
The MAX2027 integrates a fixed-gain amplifier in a neg-
ative feedback topology. This fixed-gain amplifier is
optimized for a frequency range of operation from
50MHz to 400MHz with a high-output third-order inter-
cept point (OIP3). The bias current is chosen to opti-
mize the IP
current consumption is 60mA while exhibiting a typical
40dBm output IP
The fixed-gain amplifier output port requires an external
pullup choke inductor to V
bias inductor of 330nH from AMP
(pin 14). At the output, connect a 680nH choke inductor
from RF_OUT (pin 12) to V
current to the amplifier.
A properly designed PC board is an essential part of
any RF/microwave circuit. Keep RF signal lines as short
as possible to reduce losses, radiation, and induc-
IF Digitally Controlled Variable-Gain Amplifier
*FOR EXTERNAL MATCHING
RF IN
3
C
of the amplifier. When R
1
C
3
8
*
_______________________________________________________________________________________
CONTROL
at 50MHz.
INPUTS
V
CC
Layout Considerations
CC
CC
Fixed-Gain Amplifier
. At the input, connect a
R
(pin 11) to provide bias
6
L
V
3
R
CC
IN
Choke Inductor
*
5
(pin 15) to I
C
R
7
4
1
is 825Ω, the
R
3
R
2
C
2
BIAS
B4
B3
B2
B1
B0
10
1
2
3
4
5
6
7
8
9
ATTENUATION
tance. For the best performance, route the ground pin
traces directly to the exposed pad under the package.
Solder the exposed pad on the bottom of the device
package evenly to the board ground plane to provide a
heat transfer path along with RF grounding.
Proper voltage-supply bypassing is essential for high-
frequency circuit stability. Bypass each V
1000pF and 100pF capacitor. Connect the 100pF
capacitor as close to V
The exposed paddle (EP) of the MAX2027’s 20-pin
TSSOP-EP package provides a low thermal-resistance
path to the die. It is important that the PC board on
which the MAX2027 is mounted be designed to con-
duct heat from the EP. In addition, provide the EP with
a low-inductance path to electrical ground. The EP
should be soldered to a ground plane on the PC board,
either directly or through an array of plated via holes.
CONTROL
LOGIC
Exposed Pad RF/Thermal Considerations
MAX2027
AMP
BIAS
20
19
18
17
16
15
14
13
12
11
ATTN
AMP
I
I
BIAS
SET
IN
OUT
CC
Power-Supply Bypassing
R
1
L
4
pins as possible.
*
C
C
5
3
L
L
2
1
C
9
C
*
4
C
6
CC
C
10
RF OUT
V
CC
pin with a
9