SN54ALS526, SN54ALS527, SN54ALS528

SN74ALS526, SN74ALS527, SN74ALS528

FUSE-PROGRAMMABLE IDENTITY COMPARATORS

SDAS051A – JUNE 1984–REVISED MAY 1986

POST OFFICE BOX 655303

6

programing parameters

PARAMETER

MIN

MAX

UNIT

VIH

High-level input voltage

2

5.5

V

VIL

Low-level input voltage

0.8

V

VIHH

Program-pulse input voltage

11.5

12.5

V

VCC

Supply voltage

6.5

7.5

V

IIHH

Program pulse input current

Pin (G low)

10

mA

IIHH

Program-pulse input current

G

1.24

mA

’ALS526

31

ICCHH

Supply current with VIHH applied

’ALS527

29

mA

’ALS528

26

tW

Pulse duration, program

10

50

µs

tr

Rise time, program voltage

10

µs

Test

Test

Test

Blow Fuse

Verify

Verify

Verify

VIH

VIL

VIHH

VIH

VIL

VIHH

VIL

VIH

VIL

90%

10%

90%

tw

tr

P

Inputs

Pn

G

P=Q

Don’t Care

Illustrated above is the following sequence:

NOTES: A. It is desired to program a particular input to recognize a high level input. With G low and all P inputs† at VIL, the output is low if no

fuses are blown.

B. With G low and all P inputs† at VIH, the output is high unless all fuses are blown.

C. When the desired input is taken to VIHH, the output goes low if the fuse is intact.

D. G is pulsed to VIHH blowing the desired fuse.

E. After G is low, output will be high indicating that the fuse is blown.

F. The programmed input returns to VIH, the output is high unless all fuses have been blown.

G. All P inputs† are taken to VIL, the output is high if a fuse has been blown.

† For the ’ALS527, P8 through P11 inputs must match the Q8 through Q11 inputs.

Figure 1. Programming Waveforms