TLC2933A_16 Datasheet, PDF (2/24 Pages) Texas Instruments – HIGH PERFORMANCE PHASE LOCKED LOOP

TLC2933A
HIGH PERFORMANCE PHASE LOCKED LOOP
SLES149 − OCTOBER 2005
functional block diagram
FIN−A
FIN−B
PFD INHIBIT
4
5
Phase
Frequency
6
9 ^Detector
PFD OUT
VCO IN
BIAS
VCO INHIBIT
SELECT
12
13 _Voltage
3
10
Controlled
Oscillator
2
VCO OUT
TERMINAL
NAME
NO.
LOGIC VDD
1
SELECT
2
VCO OUT
3
FIN−A
4
FIN−B
5
PFD OUT
6
LOGIC GND
7
TEST
8
PFD INHIBIT
9
VCO INHIBIT 10
VCO GND
11
VCO IN
12
RBIAS
13
VCO VDD
14
Terminal Functions
I/O
DESCRIPTION
Power supply for the internal logic. This power supply should be separated from VCO VDD to reduce
cross-coupling between supplies.
I
VCO output frequency select. When SELECT is high, the VCO output frequency is ×1/2 and when
low. The output frequency is ×1.
O VCO output. When the VCO INHIBIT is high, VCO output is low.
I
Input reference frequency f(REF _IN) is applied to FIN−A.
I
Input for VCO external counter output frequency f(FIN−B). FIN−B is nominally provided from the
external counter.
O PFD output. When the PFD INHIBIT is high, PFD output is in the high-impedance state.
GND for the internal logic.
Connect to GND.
I
PFD inhibit control. When PFD INHIBIT is high, PFD output is in the high-impedance state.
I
VCO inhibit control. When VCO INHIBIT is high, VCO output is low.
GND for VCO.
I
VCO control voltage input. Nominally the external loop filter output connects to VCO IN to control
VCO oscillation frequency.
I
Bias supply. An external resistor (RBIAS) between VCO VDD and RBIAS supplies bias for adjusting the
oscillation frequency range.
Power supply for VCO. This power supply should be separated from LOGIC VDD to reduce
cross-coupling between supplies.
2
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