CALIFORNIA MICRO DEVICES
PACDT
P/Active 1%Tolerance DualThéveninTermination Network
Features
Applications
•
•
•
•
Minimal ground bounce, crosstalk
•
HSTL termination
• Thévenin termination
ECL, TTL termination
Stable 1% absolute tolerance elements
16 terminating lines per QSOP package
Saves board space and reduces assembly cost
•
Product Description
resistance (R1 in parallel with R2) should match the
impedance of the trace. Ground-bounce and crosstalk
are virtually eliminated using a proprietary lead-frame
which includes four direct ground connections to the die
substrate, as well as four double-bonded connections to
VCC, for a total of 8 commons. In addition, the resistors
are trimmed to a tight absolute tolerance of 1% which
provides tight impedance-matching and results in greatly
reduced reflections. This unique proprietary design
provides optimal signal integrity.
High speed logic devices like HSTL (High Speed
Transceiver Logic) demand unique, high speed bus
terminations. The dual Thévenin termination network
provides 16 terminating channels per package, and
optimizes signal integrity by reducing reflections and
ringing. The terminations are available in a range of
standard values and are ideal for use in HSTL busses.
As seen in the schematic, R1 is typically tied to VCC and
serves as a pull-up resistor, while R2 functions as a pull-
down resistor and is tied to ground (or the most negative
supply voltage). In addition, the equivalent Thévenin
BUS IMPEDANCE (Ω) R1(Ω) R2 (Ω) CODE
STANDARD VALUES
47
50
56
68
94
94
001
002
003
004
Absolute Tolerance (R1 & R2)
1%
100
112
136
100
112
136
TCR
100ppm
0 C to 70 C
Operating Temperature Range
Power Rating/Resistor
Crosstalk (see Test Circuit)
Package
˚
˚
100mW
30mV TYP
24 Pin QSOP
SCHEMATIC CONFIGURATION
21
17
24
23
22 20
19
18 16
15
14
13
VCC
GND
1
2
3
4
5
6
7
8
9
10
11
12
STANDARD PART ORDERING INFORMATION
Package
Pin
Ordering Part Number
R Code
001
Style
QSOP
QSOP
QSOP
QSOP
Tubes
Tape & Reel
Part Marking
PAC001DTFQ
PAC002DTFQ
PAC003DTFQ
PAC004DTFQ
24
24
24
24
PAC001DTFQ/T
PAC002DTFQ/T
PAC003DTFQ/T
PAC004DTFQ/T
PAC001DTFQ/R
PAC002DTFQ/R
PAC003DTFQ/R
PAC004DTFQ/R
002
003
004
© 2000 California Micro Devices Corp. All rights reserved.
C1611100
215 Topaz Street, Milpitas, California 95035
Tel: (408) 263-3214
Fax: (408) 263-7846
www.calmicro.com
11/19/2000
1