RF2948B Просмотр технического описания (PDF) - RF Micro Devices

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производитель

RF2948B

2.4GHz SPREAD-SPECTRUM TRANSCEIVER

RF Micro Devices 

RF2948B

Pin

13

14

Function

PA IN

VCC5

Description

Input to the power amplifier stage. This is a 50Ω input. Requires DC-

blocking/tuning cap.

Supply for the RF LO buffer, RF upconverter and amplifier.

Interface Schematic

See pin 12.

CBYP

22 nF

From

TX VGA

VCC

CBYP

22 nF

VCC5

VB

VCC

To TX RF

Image Filter

RF OUT

12 mA

15

RF LO

16

RF OUT

17 IF1 OUT-

18 IF1 OUT+

19

TXI BP

20 TXI DATA

21

TXQ BP

22 TXQ DATA

23

VCC4

24

I OUT

25

Q OUT

T 26 VREF1 BUF

O 27

DCFB I

N 28 DCFB Q

29 BW CTRL

30

VCC2

RF LO

From

RF VCO

CBLOCK

22 pF

S Single-ended LO input for the transmit upconverter. External matching See pin 14.

to 50Ω and a DC-block are required.

N Upconverted Transmit signal. This 50Ω output is intended to drive an See pin 14.

RF filter to suppress the undesired sideband, harmonics, and other out-

of-band mixer products.

G The inverting open collector output of the quadrature modulator. This

I pin needs to be externally biased and DC isolated from other parts of

the circuit. This output can drive a Balun with IF1 OUT+, to convert to

S unbalanced to drive a SAW filter. The Balun can be either broadband

(transformer) or narrowband (discrete LC matching). Alternatively, just

E IF1 OUT+ can be used to drive a SAW single-ended with an RF choke

(high Z at IF) from VCC to IF1 OUT-.

IF1 OUT+

D The non-inverting open collector output of the quadrature modulator. See pin 17.

This pin needs to be externally biased and DC isolated from other parts

of the circuit. This output can drive a Balun with IF1 OUT-, to convert to

unbalanced to drive a SAW filter. The Balun can be either broadband

(transformer) or narrowband (discrete LC matching). Alternatively, just

W IF1 OUT+ can be used to drive a SAW single-ended with an RF choke

(high Z at IF) from VCC to IF1 OUT+.

E This is the in-phase modulator bypass pin. A 10nF capacitor to ground

N is recommended.

I input to the baseband 5 pole Bessel LPF for the transmit modulator.

This is the quadrature phase modulator bypass pin. A 10nF capacitor

to ground is recommended.

R Q input to the baseband 5 pole Bessel LPF for the transmit modulator.

Power supply for quadrature modulator.

O Baseband analog signal output for in-phase channel.

F700mVP-P linear output.

Baseband analog signal output for quadrature channel.

700mVP-P linear output.

Buffered version of the VREF1 output. See pin 31.

Sink/Source current <1mA.

DC feedback capacitor for in-phase channel. Requires capacitor to

ground. (22nF recommended)

DC feedback capacitor for quadrature channel. Requires decoupling

capacitor to ground. (22nF recommended)

This pin requires a resistor to ground to set the baseband LPF band-

width of the receiver and transmit GmC filter amps.

Supply for the I and Q baseband and GmC filters. This pin should be

bypassed with a 10nF capacitor.

IF1 OUT-

11-244

Rev A6 040930

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