MAX2685EEE Maxim Integrated Products, MAX2685EEE Datasheet - Page 7
MAX2685EEE
Manufacturer Part Number
MAX2685EEE
Description
RF Amplifier Low-Cost 900MHz Low- Noise Amplifier and
Manufacturer
Maxim Integrated Products
Type
General Purpose Amplifierr
Datasheet
1.MAX2685EEE.pdf
(10 pages)
Specifications of MAX2685EEE
Operating Frequency
1000 MHz
Noise Figure
1.4 dB at 880 MHz
Operating Supply Voltage
3 V, 5 V
Supply Current
8.5 mA
Maximum Power Dissipation
667 mW
Maximum Operating Temperature
+ 85 C
Mounting Style
SMD/SMT
Package / Case
QSOP-16
Minimum Operating Temperature
- 40 C
Number Of Channels
1 Channel
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
MAX2685EEE
Manufacturer:
MAXIM/美信
Quantity:
20 000
Company:
Part Number:
MAX2685EEE+T
Manufacturer:
MAXIM
Quantity:
7
The MAX2685 consists of five major components: a
low-noise amplifier (LNA), an LNA bypass switch, a
downconverter mixer, a local-oscillator (LO) buffer, and
a power-management block.
The LNA is a wideband, single-ended cascode amplifi-
er that operates over a wide range of frequencies. The
input of the LNA (LNAIN) requires an appropriate
matching network and a DC-blocking capacitor. The
typical operating circuit shown in Figure 1 is optimized
for frequencies around 880MHz, requiring only a 0.1µF
capacitor in series with a 12nH inductor. See Table 1
for the LNA “S” parameters for matching to other fre-
quencies.
The output of the LNA (LNAOUT) is internally biased to
V
an internal DC-blocking capacitor.
Table 1. LNA Typical S-Parameters (V
High-Gain Mode (GAIN = V CC )
Low-Gain Mode (GAIN = GND)
CC
FREQUENCY
. It is internally matched to 50Ω and incorporates
(MHz)
1000
1000
800
840
880
920
960
800
840
880
920
960
_______________________________________________________________________________________
Low-Cost, 900MHz, Low-Noise Amplifier
|
0.761
0.753
0.747
0.733
0.719
0.693
0.625
0.621
0.619
0.611
0.608
0.607
MAG
S11
Low-Noise Amplifier (LNA)
Detailed Description
|
(degrees)
PHASE
-64.5
-68.6
-73.2
-78.0
-82.8
-87.5
-45.6
-48.1
-50.9
-53.3
-55.5
-57.5
S11
|
0.188
0.195
0.199
0.200
0.200
0.200
MAG
4.98
5.06
5.07
4.91
4.68
4.40
S21
|
CC
and Downconverter Mixer
= +3V, T
(degrees)
PHASE
177.9
167.2
156.6
146.6
137.7
130.3
73.0
65.5
58.1
51.6
46.1
41.2
S21
When a large input signal is present, enable the LNA
bypass function to increase linearity and reduce supply
current. Set GAIN low to enable the LNA bypass func-
tion.
The downconverter mixer is a wideband, single-bal-
anced design with a low noise figure and high linearity.
The RF signal at the MIXIN port is mixed with the signal
at the LO port, and is downconverted to an IF frequen-
cy at the differential IF port.
The MIXIN input requires a simple external matching
network and a series DC-blocking capacitor. See
Figure 1 for a matching network example, optimized for
880MHz operation. Table 2 lists mixer “S” parameters
for matching to other frequencies.
A
= +25°C)
|
0.018
0.022
0.026
0.030
0.035
0.039
0.191
0.198
0.201
0.202
0.201
0.200
MAG
S12
|
(degrees)
PHASE
-163.7
-167.1
-171.3
-175.7
178.0
171.0
71.9
64.2
56.7
50.3
44.7
40.0
S12
LNA Bypass Switch
and Gain Control
|
0.376
0.264
0.172
0.149
0.200
0.263
0.483
0.423
0.370
0.337
0.322
0.317
MAG
S22
Receive Mixer
|
(degrees)
RF Input
PHASE
-107.3
-107.0
-94.6
-62.9
-42.4
-38.8
-91.3
-91.3
-89.9
-86.1
-80.9
-76.7
S22
7