buffers can be tristated by this function including

buffers that normally do not tristate. This test func-

tion also turns off all pull up or down devices and

shuts down all differential receivers and converts

them into standard CMOS receivers. Inside the

predriver is a section of specialized transistors used

to create the receiver functions. This section in-

cludes specialized non salicide protection resistor

diodes to further protect the gates of the receiver

devices from ESD and latch up. Also present in this

section are devices that can be utilized to form

various parameteriseable pull up, pull down and

buskeeper functions. A full set of standard receivers

with pull up and pull down devices is present in the

library. The technologies supported match the out-

put buffer capabilities and include, LVCMOS,

LVTTL, GTL, CTL, Differential, etc. and a five volt

interface capability. The last section of devices that

make up the I/O ring is a set of custom designed

(for compactness) scan latches and supporting cir-

cuits that can be utilized to form various types of

scan circuits conforming to the standard that the

customer is utilizing in his systems. These circuits

can be combined with internal transistors ifneeded.

Programmable

Pitch Bond

Pad

Input &

Control

SlewRate

Tristate

Buskeeper

Level Shifter

JTAG

Guardring

Die Core

Edge of Die

4mA

selected

Segmented

Output

River of Drive

Transistors

ISB35_PB

Figure 3. ISB35000 I/O Technology

ISB35000 SERIES

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