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MAX2387/MAX2388/MAX2389

Detailed Description

The MAX2387/MAX2388/MAX2389 include an LNA

and downconverter mixer. These devices feature a

shutdown mode to power down the IC during the front-

end receiver’s idle periods. Each IC operates from a

+2.7V to +3.3V single supply and is housed in a 12-pin

ultra-small QFN (3mm

3mm) leadless package.

The MAX2387/MAX2388/MAX2389 are fabricated using

an advanced high-frequency silicon germanium

process. The LNA and mixer NF and IIP3 have been

optimized to provide excellent RF performance in the

2110MHz to 2170MHz band, while drawing minimal

current.

For the MAX2387/MAX2388, the mixer’s performance is

optimized for a -10dBm typical drive at the LO buffer

input port. The MAX2389’s mixer performance is opti-

mized for a -4dBm typical drive at the LO input port.

The LO port for all versions can be driven either single-

ended or differentially.

LNA High/Low-Gain Mode

These devices offer two modes of operation for the LNA:

high-gain mode and low-gain mode, selectable with a

GAIN select pin. The MAX2387 has a gain of 15dB in

high-gain mode and -16.6dB in low-gain mode. The

MAX2388/MAX2389 have a gain of 15dB in high-gain

mode and -2.8dB in low-gain mode. Matching LNA in

high-gain mode will ensure matching in low-gain mode.

Downconverter Mixer

The receive mixer is a wideband, single-balanced

design with exceptional noise figure and linearity. The

LO input frequency range is 2330MHz to 2360MHz and

the RF input frequency range is 2110MHz to 2170MHz.

The mixer is internally matched to 50Ω, thus eliminating

any external matching components.

LO Input Buffers

The MAX2387/MAX2388 feature open-collector LO

buffers to increase isolation between the LO and the

rest of the system. The MAX2389 offers a lower current

consumption for applications that do not require an LO

buffer.

RF Inputs

The MIX_IN input is typically connected to the LNA out-

put through an off-chip filter providing image rejection

and out-of-band interferers filtering. The LNA input and

output require an external matching network to 50Ω.

Note that the mixer input is internally matched to 50Ω.

See Figure 1, Typical Application Circuits for 2.14GHz.

LO Inputs

The LO+ and LO- pins are internally terminated with

100Ω resistors. AC-couple the local-oscillator signal to

these pins. If a single-ended LO source is used, con-

nect LO+ to ground using an AC-coupling capacitor.

W-CDMA LNA/Mixer ICs

8 _______________________________________________________________________________________

Pin Description

PIN NAME FUNCTION

1 LNA_OUT RF Output Port for LNA. Requires external matching.

2 GAIN LNA/Mixer Gain Control Input

3 MIX_IN RF Input Port for Mixer. Internally matched to 50Ω.

4 SHDN

Shutdown Input. Drive low to enable shutdown mode. Drive high or connect to V

for normal

operation.

5 LO+

Noninverting LO Input for LO Buffer (MAX2387/MAX2388) or Mixer (MAX2389). Differential input

impedance is 200Ω. AC-couple to GND when the LO is driven single-endedly.

6 LO-

Inverting LO Input for LO Buffer (MAX2387/MAX2388) or Mixer (MAX2389). Differential input

impedance is 200Ω.

7 IF- Inverting Mixer’s IF Open-Collector Output

8 IF+ Noninverting Mixer’s IF Open-Collector Output

Supply Voltage (+2.7V to +3.3V). Capacitively bypass to GND near the IC.

10 LNA_IN RF Input Port for LNA. Requires external matching.

11 GND Ground

12 BIAS LNA/Mixer Bias Pin. For nominal bias, connect 24kΩ ±1% resistor to GND.

1 2 3 4 5 6 7 8 9 10 11

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