TABLE 8. Byte 2 of Receive Gain Instruction

Bit Number

0 dBm0 Test Level (Vrms)

76543210

at VF

00000000

No Output (Low Z to GND)

00000001

0.105

00000010

0.107

——

11111110

1.941

11111111

1.964

Applications Information

Figure 2 shows a typical ISDN phone application of the

TP3076 together with a TP3420 ISDN Transceiver “S” Inter-

face Device and HPC16400 High-Performance Microcontrol-

ler with HDLC Controller. The TP3076 device is programmed

over

its

serial

control

interface

via

the

HPC16400

POWER SUPPLIES

While the pins of the TP3076 COMBO II device are well pro-

tected against electrical misuse, it is recommended that the

standard CMOS practice of applying GND to the device be-

fore any other connections are made should always be fol-

lowed. In applications where the printed circuit card may be

plugged into a hot socket with power and clocks already

present, an extra long ground pin on the connector should be

used and a Schottky diode connected between V

GND.

To minimize noise sources all ground connections to each

device should meet at a common point as close as possible

to the GND pin in order to prevent the interaction of ground

return currents flowing through a common bus impedance.

Power supply decoupling capacitors of 0.1 µF should be

connected from this common point to V

to the device pins as possible.

Further guidelines on PCB layout techniques are provided in

CODEC/Filter Family Application Guide”.

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