Datasheet

MAX2031
Detailed Description
The MAX2031 can operate either as a downconverter or
an upconverter mixer that provides approximately 7dB of
conversion loss with a typical 7dB noise figure. IIP3 is
+36dBm for both upconversion and downconversion
modes. The integrated baluns and matching circuitry
allow for 50Ω single-ended interfaces to the RF port and
the two LO ports. The RF port can be used as an input
for downconversion or an output for upconversion. A sin-
gle-pole, double-throw (SPDT) switch provides 50ns
switching time between the two LO inputs with 49dB of
LO-to-LO isolation. Furthermore, the integrated LO buffer
provides a high drive level to the mixer core, reducing
the LO drive required at the MAX2031’s inputs to a
-3dBm to +3dBm range. The IF port incorporates a dif-
ferential output for downconversion, which is ideal for
providing enhanced IIP2 performance. For upconver-
sion, the IF port is a differential input.
Specifications are guaranteed over broad frequency
ranges to allow for use in cellular band WCDMA,
cdmaOne™, cdma2000, and GSM 850/GSM 900 2.5G
EDGE base stations. The MAX2031 is specified to oper-
ate over a 650MHz to 1000MHz RF frequency range, a
650MHz to 1250MHz LO frequency range, and a DC to
250MHz IF frequency range. Operation beyond these
ranges is possible; see the
Typical Operating
Characteristics
for additional details.
The MAX2031 is optimized for high-side LO injection
architectures. However, the device can operate in low-
side LO injection applications with an extended LO
range, but performance degrades as f
LO
decreases. See
the
Typical Operating Characteristics for measurements
taken with f
LO
below 960MHz. For a pin-compatible
device that has been optimized for LO frequencies below
960MHz, refer to the MAX2029.
RF Port and Balun
For using the MAX2031 as a downconverter, the RF
input is internally matched to 50Ω, requiring no external
matching components. A DC-blocking capacitor is
required because the input is internally DC shorted to
ground through the on-chip balun. For upconverter
operation, the RF port is a single-ended output similarly
matched to 50Ω.
LO Inputs, Buffer, and Balun
The MAX2031 is optimized for high-side LO injection
architectures with a 650MHz to 1250MHz LO frequency
range. For a device with a 570MHz to 900MHz LO fre-
quency range, refer to the MAX2029. As an added fea-
ture, the MAX2031 includes an internal LO SPDT switch
that can be used for frequency-hopping applications.
The switch selects one of the two single-ended LO
ports, allowing the external oscillator to settle on a par-
ticular frequency before it is switched in. LO switching
time is typically less than 50ns, which is more than ade-
quate for nearly all GSM applications. If frequency hop-
ping is not employed, set the switch to either of the LO
inputs. The switch is controlled by a digital input
(LOSEL): logic-high selects LO2, logic-low selects LO1.
High-Linearity, 650MHz to 1000MHz Upconversion/
Downconversion Mixer with LO Buffer/Switch
16 ______________________________________________________________________________________
Pin Description
PIN NAME FUNCTION
1, 6, 8, 14 V
CC
Power-Supply Connection. Bypass each V
CC
pin to GND with capacitors as shown in the Typical
Application Circuit.
2RFS i ng l e- E nd ed 50Ω RF Inp ut/O utp ut. Thi s p or t i s i nter nal l y m atched and D C shor ted to G N D thr oug h a b al un.
3 TAP Center Tap of the Internal RF Balun. Connect to ground.
4, 5, 10, 12,
13, 16, 17, 20
GND Ground
7 LOBIAS Bias Resistor for Internal LO Buffer. Connect a 523Ω ±1% resistor from LOBIAS to the power supply.
9 LOSEL Local Oscillator Select. Logic-control input for selecting LO1 or LO2.
11 LO1 Local Oscillator Input 1. Drive LOSEL low to select LO1.
15 LO2 Local Oscillator Input 2. Drive LOSEL high to select LO2.
18, 19 IF-, IF+ Differential IF Input/Outputs
—EP
Exposed Pad. Internally connected to GND. Solder this exposed pad to a PCB pad that uses multiple
ground vias to provide heat transfer out of the device into the PCB ground planes. These multiple ground
vias are also required to achieve the noted RF performance.
cdmaOne is a trademark of CDMA Development Group.