TX4915 View Datasheet(PDF) - Unspecified
Part Name
Description
Manufacturer
TX4915 Datasheet PDF : 9 Pages
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the wireless IC company
TX4915
Pin Descriptions
Number Name
Description
1
OSCIN
This pin is connected directly to the base of reference oscillator transistor. The
intended reference oscillator configuration is a modifiled Colpitts.
2
OSCOUT This pin is connected directly to the emitter of reference oscillator transistor.
3
TXEN
Enable control for all circuitry. When this pin is a logic “low” all circuiits are turn
off. When this pin is logic “high”, all circuits are operating normally.
4
VSS
Ground connection for the PAOUT amp.
5
PAOUT
Transmitter output. This pin is an open collector and require a pull-up inductor for
bias/matching and a tapped capacitor for matching.
6
VSS1
Ground connection for the PAOUT buffer amplifier.
7
VCC1
This pin is used to supply bias to the PA buffer amplifier.
8
MODIN
AM analog or ASK digital modulation can be imparted to the carrieer by an input to
this pin. An external resistor is used to bias the output amplifiers through this pin.
9
VCC2
This pin is used to supply DC bias to the VCO, crystal oscillator, prescaler, PFD, and
charge pump.
10 VSS2
Digital PLL ground connection.
11 VREFP Bias voltage reference pin for bypassing the prescaler.
12 RESB
13 RES
The RES pins are used to supply DC voltage to the VCO, as well as to tune the cen-
ter frequency of the VCO.
see pin 12
14 DO
Output of the charge pump. An RC network from this pin to ground is used to estab-
lish the PLL bandwidth.
15 LD
This pin is used to set the threshold of the lock detect circuit. A shunt capacitor
should be used to set an RC time constant with the on-chip series 1kΩ resistor.This
signal is used to clamp (enable or disable) the MODIN circuitry. The time constant
should be approximately 15 times the reference period.
16 SW
Logic “High” input selects divide-by-64 prescaler. Logic “Low” input selects divide-
by-128 prescsaler.
Page 2
March 2000
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