TLC2933

HIGH-PERFORMANCE PHASE-LOCKED LOOP

SLAS136A – APRIL 1996 – REVISED JUNE 1997

2

POST OFFICE BOX 655303

Terminal Functions

TERMINAL

I/O

DESCRIPTION

NAME

NO.

I/O

DESCRIPTION

BIAS

13

I

Bias supply. An external resistor (RBIAS) between VCO VDD and BIAS supplies bias for adjusting the

oscillation frequency range.

FIN – A

4

I

Input reference frequency f(REF IN) is applied to FIN – A.

FIN – B

5

I

Input for VCO external counter output frequency f(FIN – B). FIN – B is nominally provided from the external

counter.

LOGIC GND

7

Ground for the internal logic.

LOGIC VDD

1

Power supply for the internal logic. This power supply should be separate from VCO VDD to reduce

cross-coupling between supplies.

NC

8

No internal connection.

PFD INHIBIT

9

I

PFD inhibit control. When PFD INHIBIT is high, PFD OUT is in the high-impedance state, see Table 2.

PFD OUT

6

O

PFD output. When the PFD INHIBIT is high, PFD OUT is in the high-impedance state.

TEST

2

I

Test terminal. TEST connects to ground for normal operation.

VCO GND

11

Ground for VCO.

VCO IN

12

I

VCO control voltage input. Nominally the external loop filter output connects to VCO IN to control VCO

oscillation frequency.

VCO INHIBIT

10

I

VCO inhibit control. When VCO INHIBIT is high, VCO OUT is low (see Table 1).

VCO OUT

3

O

VCO output. When VCO INHIBIT is high, VCO OUT is low.

VCO VDD

14

Power supply for VCO. This power supply should be separated from LOGIC VDD to reduce cross-coupling

between supplies.

detailed description

VCO oscillation frequency

and the BIAS terminals. The oscillation frequency and range depends on this resistor value. While all resistor

values within the specified range result in excellent low temperature coefficients, the bias resistor value for the

minimum temperature coefficient is nominally 2.2 k

lock frequency range refer to the recommended operating conditions. Figure 1 shows the typical frequency

variation and VCO control voltage.

VCO Oscillation Frequency Range

Bias Resistor (RBIAS)

1/2 VDD

VCO Control Voltage (VCO IN)

Figure 1. VCO Oscillation Frequency