6

Pin Description

PIN

SYMBOL

DESCRIPTION

1

LIM1_BYP+

DC feedback pin for Limiter amplifier 1. Requires good decoupling and minimum wire length to a solid signal

ground.

2

LIM1_In+

Non inverting analog input of Limiter amplifier 1.

3

LIM1_In-

Inverting input of Limiter amplifier 1.

4

LIM1_BYP-

DC feedback pin for Limiter amplifier 1. Requires good decoupling and minimum wire length to a solid signal

ground.

5, 6,

7, 8

GND

Ground. Connect to a solid ground plane.

9

Supply pin for the Low pass filter. Use high quality decoupling capacitors right at the pin.

10

2V REF

Stable 2V reference voltage output for external applications. Loading must be higher than 10k

Ω. A bypass

capacitor of at least 0.1

µF is required.

11

LPF_BYP

0.1

µF decoupling capacitor.

12

LPF_TXI_In

Low pass filter in phase (I) channel transmit input. Conventional or attenuated direct coupling is required for digital

inputs. (Note 7)

13

LPF_TXQ_In

Low pass filter quadrature (Q) channel transmit input. Conventional or attenuated direct coupling is required for

digital inputs. (Note 7)

14

LPF_RXI_Out

Low pass filter in phase (I) channel receive output. Requires AC coupling. (Note 8)

15

LPF_RXQ_Out

Low pass filter quadrature (Q) channel receive output. Requires AC coupling. (Note 8)

16

LPF_Sel1

Digital control input pins. Selects four programed cut off frequencies for both receive and transmit channels. Tuning

speed from one cutoff to another is less than 1

µs.

SEL1

SEL0

Cutoff Frequency

SEL1

SEL0

Cutoff Frequency

LO

LO

2.2MHz

HI

LO

8.8MHz

LO

HI

4.4MHz

HI

HI

17.6MHz

17

LPF_Sel0

18

LPF_Tune1

These two pins are used to fine tune the Low pass filter cutoff frequency. A resistor connected between the two

specifications.

19

LPF_Tune0

20

GND

Ground. Connect to a solid ground plane.

21

LPF_RX_PE

Digital input control pin to enable the LPF receive mode of operation. Enable logic level is High.

22

LPF_TX_PE

Digital input control pin to enable the LPF transmit mode of operation. Enable logic level is High.

23

LPF_TXQ-

Negative output of the transmit Low pass filter, quadrature channel. AC coupling is required. Normally connects to

the inverting input of the quadrature Modulator (Mod_TXQ-), pin 40.

24

LPF_TXQ+

Positive output of the transmit Low pass filter, quadrature channel. AC coupling is required. Normally connects to

the non inverting input of the quadrature Modulator (Mod_TXQ+), pin 39.

25

LPF_TXI-

Negative output of the transmit Low pass filter, in phase channel. AC coupling is required. Normally connects to

the inverting input of the in phase Modulator (Mod_TXI-), pin 38.

26

LPF_TXI+

Positive output of the transmit Low pass filter, in phase channel. AC coupling is required. Normally connects to the

non inverting input of the in phase Modulator (Mod_TXI+), pin 37.

27

LPF_RXQ-

Low pass filter inverting input of the receive quadrature channel. AC coupling is required. This input is normally

coupled to the negative output of the quadrature demodulator (Mod_RXQ-), pin 36.

28

LPF_RXQ+

Low pass filter non inverting input of the receive quadrature channel. AC coupling is required. This input is normally

coupled to the positive output of the quadrature demodulator (Mod_RXQ+), pin 35.

29

LPF_RXI-

Low pass filter inverting input of the receive in phase channel. AC coupling is required. This input is normally

coupled to the negative output of the in phase demodulator (Mod_RXI-), pin 34.

30

LPF_RXI+

Low pass filter non inverting input of the receive in phase channel. AC coupling is required. This input is normally

coupled to the positive output of the in phase demodulator (Mod_RXI-), pin 33.

31, 32

GND

Ground. Connect to a solid ground plane.

HFA3724