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GND

GNDA

TESTEN

TD0-TD9

REFCLK

PRBSEN

17

22

16

SYNCEN

24

SYNC/PASS

47

10

10

RD0-RD9

2

RBC0-RBC1

ENABLE

28

TCK

49

JTMS

55

JTDI

48

JTRSTN

56

JTDO

27

LOS

26

RBCMODE

32

LOOPEN

19

MODESEL

15

Host

Protocol

Device

JTAG

Controller

VDD VDDA

2.5 V

VDDPLL

GNDPLL

5

Ω at 100 MHz

2.5 V

64

18

62

Controlled Impedance

Transmission Line

TXP

61

Controlled Impedance

Transmission Line

TXN

54

Controlled Impedance

Transmission Line

RXP

52

Controlled Impedance

Transmission Line

RXN

50

Ω

50

Ω

TLK1201AI

TLK1201AII

0.01

µF

DESIGNING WITH PowerPAD

TLK1201ARCP, TLK1201AIRCP

ETHERNET TRANSCEIVERS

SLLS580A – FEBRUARY 2004 – REVISED JUNE 2004

APPLICATION INFORMATION (continued)

Figure 12. Typical Application Circuit (AC mode)

The TLK1201A/TLK1201AI is housed in a high-performance, thermally enhanced, 64-pin VQFP (RCP64)

PowerPAD package. Use of the PowerPAD package does not require any special considerations except to note

that the PowerPAD, which is an exposed die pad on the bottom of the device, is a metallic thermal and electrical

conductor. Therefore, if not implementing PowerPAD PCB features, the use of solder masks (or other assembly

techniques) may be required to prevent any inadvertent shorting by the exposed PowerPAD of connection etches

or vias under the package. It is strongly recommended that the PowerPAD be soldered to the thermal land. The

recommended convention, however, is to not run any etches or signal vias under the device, but to have only a

grounded thermal land as explained below. Although the actual size of the exposed die pad may vary, the

minimum size required for the keepout area for the 64-pin PFP PowerPAD package is 8 mm

× 8 mm.

It is recommended that there be a thermal land, which is an area of solder-tinned-copper, underneath the

PowerPAD package. The thermal land varies in size depending on the PowerPAD package being used, the PCB

construction, and the amount of heat that needs to be removed. In addition, the thermal land may or may not

contain numerous thermal vias depending on PCB construction.

16