No. 6251-3/14

LC897127K

SCSI Pin Input Characteristics

Parameter

Symbol

Conditions

Ratings

Unit

min

typ

max

Input threshold voltage

1.60

2.00

V

0.80

1.10

V

Hysteresis width

0.41

0.5

V

Active Low Output Characteristics

Parameter

Symbol

Conditions

Ratings

Unit

min

typ

max

Output high-level voltage

2.5

V

Output low-level voltage

0.4

V

Note: Only applies to the active-low output pins DB0 to DB7, REQ, and DBPB

Rise Time Test Circuit

SCSI

Driver

TP

47

Ω±5%

15pF

±5%

2.5V

+

–

A12548

Recommended Oscillator and PLL Circuits

LC897127

R1

R2

C2

C1

XTALCK0

PN27

XTAL0

PN28

PN69

PN70

PN71

A12549

LC897127

PLL

R5

R4

C3

R3

A12550

R1 = 120 k

Ω, R2 = 47 Ω, C1 = 30 pF

Crystal element oscillator frequency XTALCK0 = 16.9344 MHz

R3 = 7.5 k

Ω, R4 = 200 Ω, R5 = 10k Ω, C3 = 0.1 µF

Note: The values listed above for R3, R4, R5, and C3 also apply when the XTALKC0 frequency is 33.8688 MHz.

logic system power supply and is not affected by the logic system power supply in any way.

Since the exact values of these components will vary depending on characteristics of the printed circuit board used and

other factors, consult the manufacturer of the crystal element when designing the oscillator circuit.