PCI1211 datasheet(21/130 Pages) TI

21 / 130 page

PCI1211 GGU/PGE

PC CARD CONTROLLERS

SCPS033A – OCTOBER 1998

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

power supply sequencing

The PCI1211 contains 3.3-V I/O buffers with 5-V tolerance requiring a core power supply and clamp voltage.

The core power supply is always 3.3 V. The clamp voltage can be either 3.3 V or 5 V, depending on the interface.

The following power-up and power-down sequences are recommended.

The power-up sequence is:

Apply 3.3-V power to the core.

Assert PRST to the device to disable the outputs during power up. Output drivers must be powered up in

the high-impedance state to prevent high current levels through the clamp diodes to the 5-V supply.

Apply the clamp voltage.

The power-down sequence is:

Use PRST to switch outputs to a high-impedance state.

Remove the clamp voltage.

Remove the 3.3-V power from the core.

I/O characteristics

Figure 1 shows a 3-state bidirectional buffer. The

recommended operating conditions table, on page 119,

provides the electrical characteristics of the inputs and outputs.

NOTE:

The PCI1211 meets the ac specifications of the

1997 PC Card Standard and PCI Local Bus

Specification Revision 2.2.

Tied for Open Drain

Pad

VCCP

Figure 1. 3-State Bidirectional Buffer

NOTE:

Unused pins (input or I/O) must be held high or low to prevent them from floating.

clamping voltages

The clamping voltages are set to match whatever external environment the PCI1211 will be working with: 3.3 V

or 5 V. The I/O sites can be pulled through a clamping diode to a voltage that protects the core from external

signals. The core power supply is always 3.3 V and is independent of the clamping voltages. For example, PCI

signaling can be either 3.3 V or 5 V, and the PCI1211 must reliably accommodate both voltage levels. This is

accomplished by using a 3.3-V I/O buffer that is 5-V tolerant, with the applicable clamping voltage applied. If

a system designer desires a 5-V PCI bus, VCCP can be connected to a 5-V power supply.

The PCI1211 requires three separate clamping voltages because it supports a wide range of features. The three

voltages are listed and defined in the

recommended operating conditions, on page 119.

PCI1211 датащи(PDF) 21 Page - Texas Instruments

PCI1211 датащи(HTML) 21 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

датащи скачать

ссылки URL