Abstract: Bench measurement data is provided for the MAX2387 WCDMA low-noise amplifier (LNA) and mixer for a 2140MHz RF and 190MHz IF. The IF output has been re-matched for 190MHz, and the new bill of materials is provided.
The MAX2387, MAX3288, and MAX3289 are members of a family of receive front-end devices designed for WCDMA application. They integrate a low-noise amplifier (LNA) and a high-linearity downconvert mixer in an ultra-small package. The MAX2387 and MAX2388 include a local oscillator (LO) input buffer, whereas the MAX2389 eliminates the LO buffer to provide lower current consumption.
All devices feature a high-gain and low-gain mode of operation, with a 32dB gain step for the MAX2387 and an 18dB gain step for the MAX2388/MAX2389. The ICs also include a shutdown mode for powering-down the IC.
The mixer's 3rd-order nonlinearity performance can be adjusted using an external bias resistor through the BIAS_SET pin to obtain balance between desired linearity and acceptable current consumption. For the MAX2387 and MAX2388, mixer performance is optimized for a -10dBm typical drive at the LO input buffer port. The MAX2389's mixer performance is optimized for a -4dBm typical drive at the LO input port. The LO port for all versions is configurable for either single-ended or differential operation.
Measured Performance
Most of the measurement data shown below were taken on the MAX2388 with 190MHz intermediate frequency (IF) at VCC = 2.8V. The MAX2387 and MAX2389 were verified to have similar performance.
Test Conditions:
VCC = 2.8V
RF input power = -30dBm
RF frequency = 2140MHz; LO frequency = 2330MHz
Two-tone spacing = 1MHz
LO power = -10dBm (-4dBm for MAX2389)
Table 1. LNA Measurements
Parameter
High Gain
Low Gain
Units
Comments
Gain
14.6
-2.8 ( -17 MAX2387)
dB
LNA input loss = 0.2dB and LNA output loss = 0.2dB have been de-embedded
from the measurements.
NF
1.8
7.0
dB
LNA input loss = 0.2dB has been de-embedded from the measurement.
IIP3
3.5
1.0
dBm
Measured with RF = -20dBm at low-gain mode
S11
-10.5
-12.9
dB
10*log10( |S11| )
S22
-13.5
-16.5
dB
10*log10( |S22| )
S12
-25.4
-12.1
dB
10*log10( |S12| )
Icc
9.9
6.8
mA
Table 2. Mixer Measurements
Parameter
High Gain
Low Gain
Units
Comments
Gain
10.5
9.5
dB
Mixer input loss = 0.2 and IF balun insertion loss = 1.0dB have
been de-embedded.
NF
6.8
6.2
dB
Mixer input loss = 0.2dB has been de-embedded from the measurement.
IIP3
10.0
1.8
dBm
IIP2
17.0
16.8
dBm
With single-ended LO drive
IIP2
31.2
30.5
dBm
With differential LO drive
LO Leakage at IF Port
-25.5
-25.5
dBm
LO = -10 dBm @2330MHz MAX2387/88
LO Leakage at RF Port
-45
-45
dBm
LO = -10 dBm @2330MHz MAX2387/88
Table 3. S-Parameters of the LNA at High-Gain Mode
Frequency
S11
S21
S12
S22
(GHz)
Mag(dB)
Phase(Deg)
Mag(dB)
Phase(Deg)
Mag(dB)
Phase(Deg)
Mag(dB)
Phase(Deg)
1.0
-2.1286
-58.278
12.847
133.75
-32.155
74.423
-0.945
-23.033
1.1
-2.3856
-62.382
12.331
131.49
-32.022
80.579
-0.964
-25.008
1.2
-2.6618
-65.862
12.154
128
-31.585
73.547
-1.089
-24.881
1.3
-2.855
69.138
11.703
126.22
-30.677
77.068
-1.285
-25.903
1.4
-3.1572
-72.628
11.296
123.77
-31.095
76.873
-1.325
-26.516
1.5
-3.4104
-75.839
11.253
120.6
-30.572
75.955
-1.467
-26.709
1.6
-3.7441
-78.872
11.206
121.03
-30.134
77.315
-1.625
-27.577
1.7
-4.1285
-82.259
10.622
117.69
-30.08
80.001
-1.798
-28.049
1.8
-4.3986
-85.465
10.986
116.13
-29.453
82.934
-1.925
-29.221
1.9
-4.7755
-89.3
10.436
115.06
-29.922
83.366
-2.098
-29.713
2.0
-5.2184
-92.921
10.444
110.19
-29.151
84.624
-2.267
-30.994
2.1
-5.6356
-96.942
10.353
108.99
-28.898
86.776
-2.345
-32.867
2.2
-6.0176
-101
10.29
105.5
-28.514
87.56
-2.451
-35.262
2.3
-6.4621
-106.27
10.58
104.32
-27.631
89.437
-2.685
-38.079
2.4
-6.9126
-111.35
9.8114
100.88
-27.764
88.93
-2.835
-42.528
2.5
-7.2807
-117.04
10.106
95.216
-27.384
88.897
-3.018
-46.811
2.6
-7.7233
-122.7
9.7148
95.186
-26.945
88.47
-3.077
-51.827
2.7
-7.9908
-130.37
9.0991
88.322
-26.888
93.211
-3.077
-57.443
2.8
-8.2315
-137.57
9.6216
84.239
-26.285
89.688
-3.257
-63.369
2.9
-8.2342
-144.27
9.0162
85.306
-26.094
95.284
-3.305
-69.697
3.0
-8.3826
-151.69
8.5833
77.645
-26.065
91.953
-3.198
-75.708
Mixer OIM3 versus RF Input Power
Test conditions are the same for the gain, IIP3, and NF measurements stated previously.
Figure 1. MAX2388 mixer IIM3 versus pin.
Mixer IIP3 versus VCC
The mixer features very high linearity with low current consumption. Feedback is the novel technique used to improve IIP3 with low current consumption. However, the feedback is optimized at VCC = 2.7V. If VCC deviates from 2.7V, IIP3 does not obtain the optimum value of approximately +12dBm. The following figure shows the IIP3 change versus VCC.
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