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Rev.1.2 Sep.23, 2019

AX1255

2A Sink/Source Bus Termination Regulator

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GENERAL DESCRIPTION

The AX1255 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 programmed by externally forcing the REFEN pin voltage.

The AX1255 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 AX1255 are available in the SOP-8L-EP (Exposed Pad) surface mount

packages.

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FEATURES

- Ideal for DDR-I, DDR-II, DDR-III and DDR-IV 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 Voltage traces REFEN Pin Voltage.

- Low External Component Count

- Shutdown for Suspend to RAM (STR) Functionality with High-Impedance Output

- Current Limiting Protection

- Thermal Shutdown Protection

- SOP-8L with exposed pad Pb-Free Package.

- RoHS and Halogen free compliance