CALIFORNIA MICRO DEVICES
PRN102/112
DUAL THÉVENIN TERMINATION NETWORK
Features
• Stable resistor network
• 18 terminating lines/package
• Saves board space and reduces assembly cost
Applications
• SCSI termination
• Thévenin termination
Product Description
Peripheral devices like disk drives, printers, and CD
ROMs are connected to host through a special bus
called SCSI (Small Computer System Interface). The fast
edge rated signals that are transmitted through the SCSI
cable generate ringing on the bus. This will slow down
communication between host and peripherals. The SCSI
standard recommends proper resistor (Thévenin)
termination at host and peripheral locations to eliminate
transmission line effects.
CAMDs PRN102/112 Dual Thévenin Termination
Networks offer high integration and performance in a
miniature QSOP or SOIC package, which saves critical
board area and provides manufacturing cost and
reliability efficiencies.
Why thin film resistor networks? A terminating resistor is
used to reduce or eliminate unwanted reflections on a
transmission line. It can perform this function only when
its resistance value matches the characteristic imped-
ance of the transmission line. The resistors used for
terminating the transmission lines should be noiseless,
stable and functional at high frequencies. Unlike thin
film-based resistor networks, conventional thick film
resistors used for terminating transmission lines are not
stable over temperature and time and impose system
performance limitations at very high frequencies.
SCHEMATIC CONFIGURATION
20
19
18
17
16
15
14
13
12
11
1
2
3
4
5
6
7
8
9
10
S TA N D A R D S P E C I F I C AT I O N S
TCR
Operating Temperature Range
Power Rating/Resistor
Storage Temperature
Package Power Rating
±250ppm
0°C to 70°C
100mW
–65°C to +150°C
1W, max.
S TA N D A R D VA L U E S
R1 (
Ω
)
220
R2 (
Ω
)
330
Code
221/331
N O N - S TA N D A R D VA L U E S
Resistance Range
Resistance Range
R1
R2
170
Ω
to 660
Ω
110
Ω
to 440
Ω
N O N - S TA N D A R D S P E C I F I C AT I O N S
Absolute Tolerance (R)
±2%
±1%
© 2000 California Micro Devices Corp. All rights reserved.
7/14/2000
C1120600
215 Topaz Street, Milpitas, California 95035
Tel: (408) 263-3214
Fax: (408) 263-7846
www.calmicro.com
1
CALMIRCO [ CALIFORNIA MICRO DEVICES CORP ]
