TLC2932

HIGH-PERFORMANCE PHASE-LOCKED LOOP

SLAS097E – SEPTEMBER 1994 – REVISED MAY 1997

2

POST OFFICE BOX 655303

Terminal Functions

TERMINAL

I/O

DESCRIPTION

NAME

NO.

I/O

DESCRIPTION

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

GND 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 output is in the high-impedance state, see Table 3.

PFD OUT

6

O

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

BIAS

13

I

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

oscillation frequency range.

SELECT

2

I

VCO output frequency select. When SELECT is high, the VCO output frequency is

×1/2 and when low, the

output frequency is

×1, see Table 1.

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 2).

VCO GND

11

GND for VCO.

VCO OUT

3

O

VCO output. When the VCO INHIBIT is high, VCO output 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. The bias resistor

value for the minimum temperature coefficient is nominally 3.3 k

nominally 2.2 k

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