CM3109
2A Sink/Source Regulator for Front Side Bus and
DDR Memory Bus Termination
Features
•
•
•
•
•
•
•
•
•
•
Ideal for both PC Front Side Bus and DDR memory
V
TT
applications
Sinks and sources 2A
Over current protection
Over temperature protection
Shutdown function
Integrated power MOSFETs
Excellent accuracy (0.5% of load regulation)
Minimum external components
8 pin PSOP package
Lead-free version available
Product Description
The CM3109 is a sinking and sourcing regulator specif-
ically designed for series-parallel bus termination for
high speed chip set buses as well as DDR memory
systems. It can source and sink current up to 2A with
high accuracy 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 CM3109 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 PC motherboards that support both
Northwood and Prescott processors.
The CM3109 requires no external components to use
the GMCH Enable signal in Intel chipset or correspond-
ing signals for other chip sets when powering up the
PC. For the boards which support Suspend to RAM
(STR) functionality, CM3109 provides a shutdown (SD)
pin. When SD is set low, V
TT
will be in tri-state mode,
causing the output to go high impedance. In this mode,
CM3109 power is saved by significantly reducing the
quiescent current.
The CM3109 provides over current and over tempera-
ture protection. These features protect the chip from
excessive heating due to high current and high temper-
ature. The CM3109 is housed in an 8-pin PSOP pack-
age and is available with optional lead-free finishing.
Applications
•
•
•
•
PC Front Side Bus termination regulator
DDR Memory termination regulator
Active termination buses
Graphics card DDR memory termination
Simplified Electrical
Schematic
V
CC
V
DDQ
SEL FSBSEL
V
DDQ
50K
Output
Select
SD
Over Temp
Over Current
Reference
Driver
V
TT
50K
V
SENSE
GND
©
2004 California Micro Devices Corp. All rights reserved.
01/15/04
430 N. McCarthy Blvd., Milpitas, CA 95035-5112
▲
Tel: 408.263.3214
▲
Fax: 408.263.7846
▲
www.calmicro.com
1
CM3109
PACKAGE / PINOUT DIAGRAM
TOP VIEW
V
DDQ
V
TT
SD
V
SENSE
1
2
3
4
8
7
6
5
GND
V
CC
V
DDQ
SEL
GND
FSBSEL
8-lead PSOP
Note: This drawing is not to scale.
PIN DESCRIPTIONS
LEAD(S)
1
2
3
4
5
6
7
8
NAME
V
DDQ
V
TT
SD
V
SENSE
FSBSEL
GND
V
DDQ
SEL
V
CC
DESCRIPTION
Input Voltage V
DDQ
Outputs either 1.225V/1.45V FSB or V
DDQ
/2 DDR (See note 1)
Shutdown input
Feedback voltage input
Select input for FSB output. Selects either V
TT
=1.225V or 1.45V.
GROUND
Select input for DDR/FSB Output
Power for control blocks
Note 1: Assumes V
DDQ
and V
DDQ
SEL are tied together in DDR application.
Ordering Information
PART NUMBERING INFORMATION
Standard Finish
Leads
8
Package
PSOP-8
Ordering Part
Number
1
CM3109-00SB
Part Marking
CM3109-00SB
Lead-free Finish
Ordering Part
Number
1
CM3109-00SH
Part Marking
CM3109-00SH
Note 1: Parts are shipped in Tape & Reel form unless otherwise specified.
©
2004 California Micro Devices Corp. All rights reserved.
2
430 N. McCarthy Blvd., Milpitas, CA 95035-5112
▲
Tel: 408.263.3214
▲
Fax: 408.263.7846
▲
www.calmicro.com
01/15/04
CM3109
Specifications
ABSOLUTE MAXIMUM RATINGS
PARAMETER
V
CC
Operating Supply Voltage
V
DDQ
Input Voltage
Pin Voltages
V
TT
Output
Any other pins
Storage Temperature Range
Operating Temperature Range
Ambient
Junction
Power Dissipation (See note 1)
RATING
7
7
7
7
-40 to +150
-45 to +85
-45 to +150
Internally Limited
UNITS
V
V
V
V
°C
°C
°C
W
Note 1: These devices must be derated based on thermal resistance at elevated temperatures. The CM3109-xxSB/ must be der-
ated at
θ
JA
= 40
°C/W
. Please consult with factory for thermal evaluation assistance.
STANDARD OPERATING CONDITIONS
PARAMETER
V
DDQ
, V
DDQ
Ambient Operating Temperature
C
OUT
VALUE
2.5
25
220
±20%
UNITS
V
°C
μF
©
2004 California Micro Devices Corp. All rights reserved.
01/15/04
430 N. McCarthy Blvd., Milpitas, CA 95035-5112
▲
Tel: 408.263.3214
▲
Fax: 408.263.7846
▲
www.calmicro.com
3
CM3109
Performance Information
Typical DC Characteristics (nominal conditions unless otherwise specified)
Figure 1. Output Voltage with
V
CC
Supply (V
DDQ
=2.5V)
Figure 3. Reference Voltage with
V
CC
Supply (V
DDQ
=2.5V)
Figure 2. Load Regulation (Sink)
Figure 4. Load Regulation (Source)
©
2004 California Micro Devices Corp. All rights reserved.
01/15/04
430 N. McCarthy Blvd., Milpitas, CA 95035-5112
▲
Tel: 408.263.3214
▲
Fax: 408.263.7846
▲
www.calmicro.com
5
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