adl5373 Analog Devices, Inc., adl5373 Datasheet - Page 12

• Manufacturer Part Number: adl5373
• Description: 2300 Mhz To 3000 Mhz Quadrature Modulator
• Manufacturer: Analog Devices, Inc.

ADL5373
BASIC CONNECTIONS
Figure 25 shows the basic connections for the ADL5373.
Power Supply and Grounding
All the VPS pins must be connected to the same 5 V source.
Adjacent pins of the same name can be tied together and decoupled
with a 0.1 μF capacitor. These capacitors should be located as
close as possible to the device. The power supply can range
between 4.75 V and 5.25 V.
The COM1, COM2, COM3, and COM4 pins should be tied to
the same ground plane through low impedance paths. The exposed
COM1
COM1
VPS1
VPS1
VPS1
VPS1
C12
0.1µF
QBBP
1
2
3
4
5
6
GND
RLOP
OPEN
Figure 25. Basic Connections for the ADL5373
100pF
CLOP
NC
TECHNOLOGY
2450BL15B050
JOHANSON
EXPOSED PADDLE
4
5
6
QBBN
T1
F-MOD
Z1
CLON
100pF
3
2
1
IBBN
LO
RLON
OPEN
IBBP
18
17
16
15
14
13
100pF
COUT
VPS5
VPS4
VPS3
VPS2
VPS2
VOUT
0.1µF
C13
C16
0.1µF
C15
0.1µF
C14
0.1µF
OPEN
C11
VPOS
VOUT
Rev. 0 | Page 12 of 20
paddle on the underside of the package should also be soldered
to a low thermal and electrical impedance ground plane. If the
ground plane spans multiple layers on the circuit board, they
should be stitched together with nine vias under the exposed
paddle. The Application Note
and electrical grounding of the LFCSP in detail.
Baseband Inputs
The baseband inputs QBBP, QBBN, IBBP, and IBBN must be
driven from a differential source. The nominal drive level of
1.4 V p-p differential (700 mV p-p on each pin) should be
biased to a common-mode level of 500 mV dc.
The dc common-mode bias level for the baseband inputs can
range from 400 mV to 600 mV. This results in a reduction in
the usable input ac swing range. The nominal dc bias of 500 mV
allows for the largest ac swing, limited on the bottom end by the
ADL5373 input range and on the top end by the output compliance
range on most DACs from Analog Devices.
LO Input
The LO input should be driven differentially. The recommended
balun for the ADL5373 is the Johanson Technology model
2450BM15B050. The LO pins should be ac-coupled to the balun.
The nominal LO drive of 0 dBm can be increased to up to 6 dBm
to realize an improvement in the noise performance of the
modulator. If the LO source cannot provide the 0 dBm level,
then operation at a reduced power below 0 dBm is acceptable.
Reduced LO drive results in slightly increased modulator noise.
The effect of LO power on sideband suppression and carrier
feedthrough is shown in Figure 20 and Figure 21.
RF Output
The RF output is available at the VOUT pin (Pin 13). The
VOUT pin connects to an internal balun, which is capable of
driving a 50 Ω load. For applications requiring 50 Ω output
impedance, external matching is needed (see Figure 8 for S22
performance). The internal balun provides a low dc path to
ground. In most situations, the VOUT pin should be ac-coupled
to the load.
AN-772
discusses the thermal