CM3107
2 Amp Source/ Sink Bus Termination Regulator
for DDR Memory and Front Side Bus Applications
Features
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Ideal for Intel 865 Front Side Bus V
TT
and DDR
V
TT
applications
Sinks and sources 2 Amps
Over current protection
Over temperature protection
Integrated power MOSFETs
Excellent accuracy (0.5% load regulation)
Selectable output (1.225V/1.45V or V
DDQ
/2)
8-lead SOIC and PSOP packages
Lead-free versions available
Product Description
The CM3107 is a sinking and sourcing regulator specif-
ically designed for series-parallel bus termination for
high-speed chip set busses as well as DDR memory
systems. It can source and sink current up to 2.0A with
a load regulation of 0.5%. The V
TT
output voltage is
selectable by V
DDQ
SEL and FSBSEL pins. The
V
DDQ
SEL pin controls whether the CM3107 is in DDR
memory mode with V
TT
=V
DDQ
/2, or in FSB mode. In
FSB mode, FSBSEL controls whether V
TT
is 1.225V or
1.45V. This allows the same chip to be used in two dif-
ferent circuits on an Intel 865-based motherboard.
The CM3107 provides over current and over tempera-
ture protection, which protect the chip from excessive
heating due to high current and high temperature. A
shutdown capability using an external transistor
reduces power consumption and provides a high
impedance output.
The CM3107 is housed in 8-lead SOIC and PSOP
packages and is available with optional lead-free finish-
ing.
Applications
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Intel 865/845 Front Side Bus termination
Single and dual DDR memory termination
Active termination buses
Graphics card DDR memory termination
Simplified Electrical Schematic
V
CC
V
DDQ
SEL FSBSEL
V
DDQ
50K
Over Temp
Over Current
Reference
Output
Select
Driver
V
REF
OUT
IN
V
TT
50K
Buffer
V
SENSE
GND
© 2004 California Micro Devices Corp. All rights reserved.
02/02/04
430 N. McCarthy Blvd., Milpitas, CA 95035-5112
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Tel: 408.263.3214
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Fax: 408.263.7846
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www.calmicro.com
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CALMIRCO [ CALIFORNIA MICRO DEVICES CORP ]
