Datasheet ADL5331 (Analog Devices) - 9

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Data Sheet ADL5331 APPLICATIONS INFORMATION VPOS VPOS C1 C3 0.1µF 0.1µF GAIN C2 C4 100pF 100pF VPOS C15 C16 L1 0.1µF 100pF IN L 0.68µH L2 GA ENB VPS2 VPS2 VPS2 VPS2 0.68µH VPS1 VPS2 C13 C5 COM1 COM2 10nF 10nF INHI RFIN ADL5331 OPHI RFOUT INLO OPLO C14 COM1 C6 COM2 10nF 10nF VPOS VPS1 2 2 2VPS2 M M M C12 C11 PBS C7 NC IPBS O CO CO CO 0.1µF 100pF 100pF C10 C9 C8 10nF 10nF 0.1µF
017
VPOS
07593- Figure 15. Basic Connections
BASIC CONNECTIONS
To enable the ADL5331, the ENBL pin must be pul ed high. Figure 15 shows the basic connections for operating the Taking ENBL low puts the ADL5331 in sleep mode, reducing ADL5331. There are two positive supplies, VPS1 and VPS2, current consumption to 250 µA at an ambient temperature. which must be connected to the same potential. Connect COM1 The voltage on ENBL must be greater than 1.7 V to enable the and COM2 (common pins) to a low impedance ground plane. device. When enabled, the device draws 100 mA at low gain to 215 mA at maximum gain. Apply a power supply voltage between 4.75 V and 5.25 V to VPS1 and VPS2. Connect decoupling capacitors with 100 pF The ADL5331 is primarily designed for differential signals; and 0.1 µF power supplies close to each power supply pin. The however, there are several configurations that can be imple- VPS2 pins (Pins 13 and Pin 18 through Pin 22) can share a pair mented to interface the ADL5331 to single-ended applications. of decoupling capacitors because of their proximity to each other. Figure 16 and Figure 17 show options for differential-to-single- ended interfaces. Both configurations use ac-coupling capacitors The outputs of the ADL5331, OPHI and OPLO, are open at the input/output and RF chokes at the output. collectors that need to be pulled up to the positive supply
+5V
with 120 nH RF chokes. The ac-coupling capacitors and the RF chokes are the principle limitations for operation at
120nH
low frequencies. For example, to operate down to 1 MHz, use 0.1 µF ac coupling capacitors and 1.5 µH RF chokes. Note
120nH
that in some circumstances, the use of substantially larger
ADL5331
inductor values results in oscillations.
10nF RF VGA 10nF RFIN INHI OPHI RFOUT
Because the differential outputs are biased to the positive
INLO OPLO
supply, ac-coupling capacitors (preferably 100 pF) are needed
10nF 10nF
018 between the ADL5331 outputs and the next stage in the system.
ETC1-1-13 ETC1-1-13
07593- Similarly, the INHI and INLO input pins are at bias voltages of Figure 16. Differential Operation with Balun Transformers about 3.3 V above ground. Figure 16 illustrates differential balance at the input and output The nominal input and output impedance looking into each using a transformer balun. Input and output baluns are recom- individual RF input/output pin is 25 Ω. Consequently, the mended for optimal performance. Much of the characterization differential impedance is 50 Ω. for the ADL5331 was completed using 1:1 baluns at the input and output for a single-ended 50 Ω match. Operation using M/A-COM ETC1-1-13 transmission line transformer baluns is recommended for a broadband interface; however, narrow- band baluns can be used for applications requiring lower insertion loss over smaller bandwidths. Rev. A | Page 9 of 15 Document Outline FEATURES APPLICATIONS FUNCTIONAL BLOCK DIAGRAM GENERAL DESCRIPTION REVISION HISTORY SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION APPLICATIONS INFORMATION BASIC CONNECTIONS GAIN CONTROL INPUT CMTS TRANSMIT APPLICATION Interfacing to AD9789 INTERFACING TO AN IQ MODULATOR SOLDERING INFORMATION EVALUATION BOARD SCHEMATIC OUTLINE DIMENSIONS ORDERING GUIDE