Advanced Power
Electronics Corp.
2A SINK/SOURCE BUS TERMINATION REGULATOR
FEATURE
DESCRIPTIOON
Ideal for DDR-I, DDR-II and DDR-III VTT Applications
Sink and Source 2A Continuous Current
Integrated Power MOSFETs
Generates Termination Voltage for SSTL_2, SSTL_18,
HSTL, SCSI-2 and SCSI-3 Interfaces.
High Accuracy Output Voltage at Full-Load
Output Adjustment by Two External Resistors
Low External Component Count
Shutdown for Suspend to RAM (STR) Functionality
with High-Impedance Output
Current Limiting Protection
On-Chip Thermal Protection
Available in ESOP-8 (Exposed Pad) & SO-8 Packages
VIN and VCNTL No Power Sequence Issue
RoHS Compliant and 100% Lead (Pb)-Free
APPLICATIO
Desktop PCs, Notebooks, and Workstations
Graphics Card Memory Termination
Set Top Boxes, Digital TVs, Printers
Embedded Systems
Active Termination Buses
DDR-I, DDR-II and DDR-III Memory Systems
Data and specifications subject to change without notice
201003052
AP1280
TYPICAL APPLICATION
1
The AP1280 is a simple, cost-effective and high-
speed linear regulator designed to generate termination
voltage in double data rate (DDR) memory system to
comply with the JEDEC SSTL_2 and SSTL_18 or other
specific interfaces such as HSTL, SCSI-2 and SCSI-3
etc. devices requirements. The regulator is capable of
actively sinking or sourcing up to 2A while regulating an
output voltage to within 40mV. The output termination
voltage cab be tightly regulated to track 1/2VDDQ by two
external voltage divider resistors or the desired output
voltage can be pro-grammed by externally forcing the
REFEN pin voltage.
The AP1280 also incorporates a high-speed
differential amplifier to provide ultra-fast response in
line/load transient. Other features include extremely low
initial offset voltage, excellent load regulation, current
limiting in bi-directions and on-chip thermal shut-down
protection.
The AP1280 are available in the ESOP-8
(Exposed Pad) & SO-8 surface mount packages.
VIN VCNTL
REFEN VOUT
GND
RTT
EN
VIN=2.5V/1.8V/1.5V
VCNTL=3.3V
R1
R2CSS
CIN
COUT
CCNTL
2N7002 AP1280
RDUMMY
R1 = R2 = 100KΩ, RTT = 50Ω / 33Ω / 25Ω
COUT,min = 10uF (Ceramic) + 100uF under the worst case testing condition
CSS = 1µF, CIN = 470µF(Low ESR), CCNTL = 47µF