2-3

27

SYN_VCC2

Synthesizer Positive Power Supply.

29

CP_VCC2

Synthesizer Charge Pump Positive Power Supply.

30

CP_DO

Synthesizer Charge Pump Output, feeds the PLL loop filter.

32

LD

Synthesizer Lock Detect Output.

33

TX_MX_VCC1

Transmit Mixer Positive Power Supply.

34

TX_MX_OUT

Transmit Mixer RF output, internal AC coupled and internally matched to 50

Ω.

35

TX_MX_VCC1

Transmit Mixer Positive Power Supply.

36

TX_MX_VCC1

Transmit Mixer Positive Power Supply.

37

TX_MX_VCC1

Transmit Mixer Positive Power Supply.

38

TX_LO_Driver_

VCC1

Transmit LO Driver Positive Power Supply.

40

LO_IN+

Local Oscillator Positive Input, internally AC coupled, internally matched to 50

Ω when the LO is driven single ended

and the LO_IN- is grounded.

41

LO_IN-

Local Oscillator Negative Input, internally AC coupled, differential or single ended capability, ground externally for single

ended operation.

43

LO_VCC1

LO Buffer Positive Power Supply.

45

RX_LO_DRIVER

_VCC1

Receiver LO Driver Positive Power Supply.

47

TX_MX_IN-

Transmit Mixer Negative Input, internally DC coupled, high impedance input. Designed to share a common IF matching

network/IF SAW filter with the receive mixer. Care should be exercised regarding the PC board layout to avoid

interference and noise pickup. Layout symmetry and management of PC board parasitics is also critical for maximizing

the bandwidth of the IF matching network.

48

RX_MX_OUT-

Receive Mixer Negative Output, open collector, high impedance output. Designed to share a common IF matching

network/IF SAW filter with the transmit mixer. Care should be exercised regarding the PC board layout to avoid

interference and noise pickup. Layout symmetry and management of PC board parasitics is also critical for maximizing

the bandwidth of the IF matching network.

49

RX_MX_OUT+

Receive Mixer Positive Output, open collector, high impedance output. Designed to share a common IF matching

network/IF SAW filter with the transmit mixer. Care should be exercised regarding the PC board layout to avoid

interference and noise pickup. Layout symmetry and management of PC board parasitics is also critical for maximizing

the bandwidth of the IF matching network.

50

TX_MX_IN+

Transmit Mixer Positive Input, internally DC coupled, high impedance input. Designed to share a common IF matching

network/IF SAW filter with the receive mixer. Care should be exercised regarding the PC board layout to avoid

interference and noise pickup. Layout symmetry and management of PC board parasitics is also critical for maximizing

the bandwidth of the IF matching network.

52

RX_MX_IN

Receive Mixer RF Input, internally DC coupled and requires external AC coupling as well as RF matching. The

recommend network consists of a 3.3pF series capacitor followed by a small series inductance of 1.4nH and then a

1.2nH shunt inductor. The series inductance is best implemented on the PC board using a narrow transmission line

inductor.

54

PRE_VCC1

PLL Prescaler Positive Power Supply.

56

ITAT_RES1

Connection to external resistor sets the receive and transmit mixers tail currents, independent of Absolute Temperature.

57

PTAT_RES

Connection to external resistor sets the receive and transmit mixers tail currents, proportional to Absolute Temperature.

58

BIAS2_VCC1

Bias Positive Power Supply for the receive and transmit mixers.

59

ITAT_RES2

Connection to external resistor sets the LNA and Preamplifier bias currents, independent of Absolute Temperature.

61

RF_OUT

Low Noise Amplifier RF Output, internally AC coupled and internally matched to 50

Ω.

63

COL_OUT

LNA Collector Output, requires a bypass capacitance which is resonant with the PC board parasitics. A small resistance

(20

Ω) in series with the main PC board VCC buss is recommended to provide isolation from other VCC bypass

capacitors. This ensures the image rejection performance of the LNA is maintained.

All

Others

GND

Circuit Ground Pins (Quantity 23 each).

PIN

NAME

DESCRIPTION

HFA3683A