RT9089AGQW(2)

RT9089A is a sink/source tracking termination regulator designed for low-cost systems with minimal external component count. It features a high-speed op-amp for fast load transient response, requiring only a minimum 10μF ceramic output capacitor. The regulator supports remote sensing and incorporates all features required to power DDRI/DDRII/DDRIII/DDRIV/LPDDRII/LPDDRIII VTT bus termination, compliant with JEDEC specifications. The RT9089A is housed in a thermally efficient WDFN-10L 2x2 package. It is a linear sink/source DDR termination regulator with a current capability of up to 2A. It integrates a high-side N-MOSFET for sourcing current and a low-side N-MOSFET for sinking current. All control circuitry is powered by the VCNTL supply. During normal operation, the error amplifier OP adjusts the gate drive voltage of the power MOSFETs so that the SENSE voltage accurately tracks the VDDQSNS/2 voltage. Both source and sink currents are monitored via internal sense resistors; when an overload occurs, the overcurrent protection (OCP) function activates to limit the current to its designed value. Additionally, if VOUT exceeds the normal operating window, the current folds back to half. This function provides a REFOUT output level equal to VDDQSNS/2 with 10mA source/sink current capability. The device includes VCNTL undervoltage lockout (UVLO), VDDQSNS undervoltage lockout, and enable/disable functions, providing logic control for the entire chip. When the junction temperature exceeds a typical value of 160°C, both the high-side and low-side power MOSFETs are shut down; normal operation resumes when the junction temperature drops below a typical value of 120°C. The RT9089A input pins S3 and S5 allow simple control of power states. Table 1 describes the S3/S5 terminal logic states and the corresponding states of the REFOUT/VOUT outputs. In the S3 state, VOUT is turned off and discharged to ground. When both the S5 and S3 pins are low, the power state is set to S4/S5. In the S4/S5 state, all outputs are turned off and discharged to ground.

Applications

• Notebook/Desktop/Server
• Telecom/Datacom, GSM base stations, LCD/Plasma TV, Copier/Printer, Set-top box

Key features

• Input voltage range VIN: 1.1V ~ 3.5V
• Input voltage range VCNTL: 2.9V ~ 5.5V
• Ceramic capacitor compatible
• 10mA source/sink reference output
• Compliant with DDRI, DDRII JEDEC specifications
• Supports DDRIII, DDRIV, LPDDRII, and LPDDRIII applications
• Soft-start function
• UVLO and OCP
• Thermal shutdown