AK2401 Datasheet, PDF (31/103 Pages) Asahi Kasei Microsystems – Direct Conversion Transceiver

[AK2401]
LG
LD
C1
Diode
Limiter
28. LNAIN
C2
VBIAS1
LS
29. LNACONT
Figure 16. Equivalent Circuit for LNA Input Block
An equivalent circuit at the LNA output is shown in Figure 17. The LNAOUT pin is an open drain pin.
Connect the LNAOUT pin to VDD1 via an L1 inductor to supply DC voltage. A load resistance RL should
also be connected to the LNAOUT pin in parallel with the L1. The load resistance value can be changed if
necessary. Normally, electric characteristics of the AK2401 are assuming to connect a 200Ω load
resistance. The C4 is an AC coupling capacitor. The L1 and C4 also work as matching elements for
impedance conversion.
VBIAS2
L1
RL
25. LNAOUT
C4
Figure 17. Equivalent Circuit for LNA Output Block
An external filter can be connected between the LNA and MIXER pins according to a desired image
rejection characteristic.
017003093-E-00
31
2017/3