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Texas Instruments LP2997MRX/NOPB
- Part No.:
- LP2997MRX/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- Power Management - Specialized
- Package:
- 8-PowerSOIC (0.154", 3.90mm Width)
- Datasheet:
-
LP2997MRX/NOPB.pdf
- Description:
- IC DDR-II TERM REG 8SOPWRPAD
- Quantity:
- Payment:
- Shipping:
Inventory:17,840
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Product details
Overview
LP2997MRX/NOPB from Texas Instruments is a linear DDR-II termination regulator designed specifically for SSTL-18 bus termination. It sources and sinks up to ±500 mA continuous current, regulates VTT to precisely VDDQ/2 (e.g., 0.9 V at VDDQ = 1.8 V), and features integrated VREF buffer and active-low shutdown for Suspend-to-RAM functionality-used in high-speed memory subsystems of desktop, server, and embedded DDR2 platforms.
For engineers reviewing the LP2997MRX/NOPB datasheet, LP2997MRX/NOPB pinout, LP2997MRX/NOPB application, or LP2997MRX/NOPB equivalent, key selection considerations include its dual-rail architecture (AVIN/PVIN separation), remote-sense VSENSE capability, thermal shutdown behavior, SO PowerPAD-8 package thermal performance (θJA = 43°C/W), and JEDEC SSTL-18 compliance.
Technical Context
The LP2997MRX/NOPB implements a linear topology with split analog (AVIN) and power (PVIN) rails to minimize internal dissipation and improve regulation accuracy. Its internal reference derives VREF = VDDQ/2 via matched 50 kΩ resistors, enabling precise tracking independent of PVIN variations.
VTT regulation uses a high-speed op-amp feedback loop referenced to VSENSE, supporting both local and remote sensing configurations. The output stage prevents shoot-through while delivering bidirectional current, and the SD pin enables tri-state VTT with persistent VREF during low-power states.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VTT Output Voltage | 0.908 V (typ) at VDDQ = 1.8 V, IOUT = 0 A - matches JEDEC SSTL-18 termination requirement exactly |
| Output Current Capability | ±500 mA continuous, ±900 mA transient - sufficient for full DDR2 DIMM termination loads |
| VREF Accuracy | ±27 mV over temperature (0.887–0.937 V at VDDQ = 1.8 V) - ensures stable chipset and DIMM reference |
| Quiescent Current | 500 µA (max) at TJ = 125°C - enables low-power operation in active state |
| Shutdown Quiescent Current | 150 µA (max) - reduces system standby power while maintaining VREF |
| Thermal Shutdown Threshold | 165°C with 10°C hysteresis - protects against sustained overload or poor PCB thermal design |
| Package Thermal Resistance | θJA = 43°C/W (SO PowerPAD-8) - enables higher power handling vs. SOIC-8 (151°C/W) |
Pinout & Package
LP2997MRX/NOPB is housed in an 8-pin SO PowerPAD package (TI package code DDA), featuring an exposed thermal pad (EP) that must be soldered to a PCB ground plane for optimal thermal performance. The package supports JEDEC Level-3 moisture sensitivity and 260°C peak reflow.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 GND | Ground reference | Common return for analog and power sections; connects to EP for thermal path |
| 2 SD | Active-low shutdown control | Pulling low disables VTT (tri-state) but keeps VREF active for STR mode |
| 3 VSENSE | Remote feedback sense | Enables improved load regulation by connecting to midpoint of VTT distribution plane |
| 4 VREF | Buffered reference output | Provides stable VDDQ/2 (e.g., 0.9 V) to chipset/DIMM; remains active in shutdown |
| 5 VDDQ | Reference input rail | Direct connection to DDR2 memory VDDQ rail (typically 1.8 V); sets VREF and VTT target |
| 6 AVIN | Analog supply input | Powers internal op-amps and logic (2.2–5.5 V range); isolated from PVIN to reduce noise coupling |
| 7 PVIN | Power supply input | Supplies output stage only (1.8 V or 2.5 V typical); must be ≤ AVIN to prevent damage |
| 8 VTT | Regulated termination output | Bidirectional output (±500 mA) tied to DDR2 termination resistors; regulated to VDDQ/2 |
| EP Exposed Pad | Thermal & electrical ground | Must be soldered to large PCB copper area connected to GND for thermal management and EMI reduction |
Key Features
| Feature | Design Value |
|---|---|
| Source/sink termination regulator | Delivers ±500 mA continuous bidirectional current without external MOSFETs or complex control |
| VDDQ/2 reference generation | Internal precision resistor divider eliminates need for external resistors or trimming |
| VSENSE remote sensing | Compensates for IR drop across long VTT planes, improving voltage uniformity across DDR2 bus |
| Suspend-to-RAM (STR) support | SD pin asserts tri-state VTT while preserving VREF - enables low-power memory retention |
| Split-rail architecture | Separate AVIN (analog) and PVIN (power) inputs reduce thermal stress and improve PSRR |
| Thermal shutdown with hysteresis | 165°C trip with 10°C hysteresis prevents oscillation during thermal overload recovery |
Applications
| DDR2 Memory Termination | SSTL-18 Bus Regulation |
|---|---|
|
Use Scenario: Termination of address/control/data buses on DDR2 SDRAM modules in desktop motherboards. IC Role / Device Role / Timing Role: Provides dynamically regulated VTT = VDDQ/2 to match JEDEC SSTL-18 specifications, sourcing/sinking transient currents during bus switching. Use Value: Eliminates need for discrete resistor networks and external regulators, reducing BOM count and layout complexity while ensuring signal integrity at 400–800 MT/s data rates. |
Use Scenario: Termination of high-speed parallel buses in networking switches using DDR2-based packet buffers. IC Role / Device Role / Timing Role: Acts as a precision, low-noise VTT source synchronized to VDDQ, with VSENSE connected at bus midpoint for uniform voltage distribution. Use Value: Maintains <±25 mV VTT offset under ±500 mA load steps, preventing timing skew and signal reflection across multi-drop topologies. |
| Server Memory Subsystem | Embedded DDR2 Controller Interface |
|
Use Scenario: Termination for registered DDR2 DIMMs in 1U rack servers with constrained thermal budgets. IC Role / Device Role / Timing Role: Delivers high-current VTT with SO PowerPAD-8 thermal performance (θJA = 43°C/W), enabling reliable operation at 125°C junction temperature. Use Value: Supports continuous 500 mA sourcing/sinking without derating in dense layouts, reducing need for heatsinks or airflow augmentation. |
Use Scenario: Termination for DDR2 interfaces in industrial PLCs with Suspend-to-RAM power management. IC Role / Device Role / Timing Role: Uses SD pin to tri-state VTT during low-power sleep while maintaining active VREF for fast wake-up and memory retention. Use Value: Achieves <150 µA shutdown current, extending battery-backed operation time without compromising memory state integrity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar DDR-II termination regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS51100PWR | Switching architecture; higher efficiency but requires external inductor/filter; no integrated VREF buffer | Preferred where >85% efficiency is critical and board space allows inductor placement | Choose TPS51100PWR when thermal limits prevent linear regulator use; accept added component count and noise filtering requirements |
| LP2998MRX/NOPB | Same SO PowerPAD-8 package; adds enable-controlled VREF shutdown and tighter VTT accuracy (±15 mV) | Used in next-gen DDR2 designs requiring lower VTT tolerance and coordinated power sequencing | Choose LP2998MRX/NOPB when VTT stability below ±20 mV is required or when VREF gating improves system-level power management |
Compared with LP2997MRX/NOPB, TPS51100PWR reduces thermal load but increases design complexity and EMI risk, while LP2998MRX/NOPB offers enhanced precision and control at marginally higher cost-neither is pin-compatible, requiring layout revision.
Availability
LP2997MRX/NOPB is available at Aetrix Electronics and suitable for DDR2 memory termination, SSTL-18 bus regulation, and embedded Suspend-to-RAM systems requiring stable component supply, JEDEC-compliant performance, and SO PowerPAD thermal reliability.
Supply support for LP2997MRX/NOPB includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and digital signal technologies, with decades of expertise in power management ICs for memory and computing systems.
The LP2997MRX/NOPB belongs to TI's DDR termination regulator product line, engineered specifically to meet JEDEC SSTL-18 requirements for DDR2 SDRAM systems-emphasizing precision, bidirectional current capability, and low-power STR functionality.
FAQ
What is the primary function of LP2997MRX/NOPB in a DDR2 memory system?
The LP2997MRX/NOPB serves as a linear termination regulator that generates and maintains the VTT voltage at exactly VDDQ/2 (e.g., 0.9 V when VDDQ = 1.8 V) for DDR2 SSTL-18 buses. It actively sources and sinks up to ±500 mA to compensate for dynamic bus switching, ensuring signal integrity and compliance with JEDEC specifications. Its integrated VREF buffer and VSENSE remote sensing further enhance accuracy and distribution uniformity across the memory interface.
How does the VSENSE pin improve performance in LP2997MRX/NOPB applications?
The VSENSE pin on the LP2997MRX/NOPB enables remote feedback sensing, allowing regulation to occur at the point of load rather than at the regulator output. When connected to the midpoint of the VTT distribution plane-such as on a motherboard with long trace runs-it compensates for IR drop, ensuring consistent termination voltage across all DDR2 devices. This directly improves signal eye margin and reduces timing skew, especially critical in high-density, high-speed memory layouts.
Can LP2997MRX/NOPB be used with DDR3 or DDR4 memory interfaces?
No, the LP2997MRX/NOPB is specifically designed and characterized for DDR2/SSTL-18 compliance, targeting a VTT = VDDQ/2 = 0.9 V nominal. DDR3 uses SSTL-15 (0.75 V) and DDR4 uses POD-12 (0.6 V), requiring different reference ratios and current capabilities. TI offers dedicated regulators like LP2996 (DDR3) and TPS51200 (DDR3/DDR4) for those standards; substituting LP2997MRX/NOPB would violate JEDEC voltage tolerances and load regulation requirements.
What is the role of the SD (shutdown) pin in LP2997MRX/NOPB, and how does it behave during assertion?
The SD pin on the LP2997MRX/NOPB is an active-low control that places the VTT output in high-impedance (tri-state) mode while keeping VREF fully active-enabling Suspend-to-RAM functionality. When SD is pulled low, quiescent current drops to ≤150 µA, eliminating VTT load current and reducing system standby power. Critically, VREF remains stable to preserve memory reference integrity, allowing rapid wake-up without recalibration. The SD pin includes an internal pull-up, so it may be left floating to maintain normal operation.
Why does LP2997MRX/NOPB use separate AVIN and PVIN supply pins?
LP2997MRX/NOPB separates AVIN (analog supply) and PVIN (power supply) to isolate noise-sensitive control circuitry from high-current output switching. AVIN powers the error amplifier, reference, and logic (2.2–5.5 V), while PVIN supplies only the output stage (1.8 V or 2.5 V). This split-rail architecture minimizes PSRR degradation, reduces thermal coupling between analog and power sections, and allows optimized PCB routing-resulting in tighter VTT regulation, lower output noise, and improved thermal headroom compared to single-supply alternatives.
LP2997MRX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-PowerSOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Last Time Buy
- Applications:
- DDR-II Terminator
- Current - Supply:
- 320µA
- Voltage - Supply:
- 2.2V ~ 5.5V
- Operating Temperature:
- 0°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO PowerPad
LP2997MRX/NOPB FAQ
1.How can I place an order for LP2997MRX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LP2997MRX/NOPB on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LP2997MRX/NOPB reliable?
The price and inventory of LP2997MRX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP2997MRX/NOPB is usually 5 days.
3.What payment methods are accepted for LP2997MRX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP2997MRX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP2997MRX/NOPB?
LP2997MRX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP2997MRX/NOPB order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LP2997MRX/NOPB?
For technical support, including LP2997MRX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP2997MRX/NOPB requirements.
6.How does Aetrix verify that LP2997MRX/NOPB is sourced from the original manufacturer or authorized distributors?
All LP2997MRX/NOPB products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LP2997MRX/NOPB meets industry standards.
7.What is the process for return or replacement of LP2997MRX/NOPB?
All LP2997MRX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LP2997MRX/NOPB, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LP2997MRX/NOPB part is unused and in its original packaging.
Return procedure for LP2997MRX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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