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Texas Instruments LP2997MR
- Part No.:
- LP2997MR
- Manufacturer:
- Texas Instruments
- Category:
- Power Management - Specialized
- Package:
- 8-PowerSOIC (0.154", 3.90mm Width)
- Datasheet:
-
LP2997MR.pdf
- Description:
- IC DDR-II TERM REG 8SOPWRPAD
- Quantity:
- Payment:
- Shipping:
Inventory:1,106
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Product details
Overview
LP2997MR from Texas Instruments is a linear DDR-II termination regulator designed specifically for SSTL-18 bus termination, delivering ±500 mA continuous sourcing/sinking current with 0.9 V output (VTT = VDDQ/2), 0.860 V typical VREF, and thermal shutdown protection. It operates with AVIN = 2.2–5.5 V and PVIN = 1.8 V, supporting high-impedance tri-state VTT during Suspend-to-RAM mode.
For engineers reviewing the LP2997MR datasheet, LP2997MR pinout, LP2997MR application, or LP2997MR equivalent, this page delivers verified electrical parameters, SO PowerPAD-8 package layout, DDR-II memory interface design guidance, and validated alternative options for termination voltage regulation in high-speed memory subsystems.
Technical Context
The LP2997MR integrates dual-input power architecture (AVIN for analog control, PVIN for output stage) to minimize internal power dissipation and improve thermal performance. Its VSENSE pin enables remote load regulation across distributed DDR-II termination buses, while VREF provides a buffered, low-impedance (2.5 kΩ) reference at precisely VDDQ/2.
It implements a linear topology with shoot-through prevention, active-low SD pin for STR functionality, and internal 50 kΩ resistor divider for VDDQ-based reference generation. The device maintains stable VTT regulation under ±900 mA transient loads and supports operation from 0°C to +125°C junction temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VTT Output Voltage | 0.908 V (typ) at VDDQ = 1.8 V; tracks VDDQ/2 with ±25 mV offset over full load range. |
| Output Current | ±500 mA continuous; ±900 mA peak transient - sufficient for full DDR-II DIMM termination. |
| VREF Output | 0.910 V (typ) buffered reference; 2.5 kΩ output impedance ensures stable chipset/DIMM reference. |
| Quiescent Current | 500 µA (typ) in active mode; drops to 150 µA in shutdown - critical for low-power STR states. |
| Thermal Shutdown | 165°C trip point with 10°C hysteresis - protects against sustained overload in compact layouts. |
| Package Thermal Resistance | θJA = 43°C/W (SO PowerPAD-8) - enables higher power handling vs. SOIC-8 (151°C/W). |
| Input Voltage Range | AVIN: 2.2–5.5 V; PVIN: ≤ AVIN, typically 1.8 V - allows split-rail optimization for thermal efficiency. |
Pinout & Package
LP2997MR is packaged in SO PowerPAD-8 (Package Code DDA), featuring an exposed thermal pad (EP) connected to GND for enhanced heat dissipation. This package delivers 43°C/W junction-to-ambient thermal resistance - significantly lower than SOIC-8 - making it suitable for high-current DDR-II termination in space-constrained motherboard designs.
| 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 | Tri-states VTT while keeping VREF active for Suspend-to-RAM; VIH ≥ 1.9 V, VIL ≤ 0.8 V. |
| 3 (VSENSE) | Remote feedback sense | Enables precise VTT regulation at bus midpoint; must connect to VTT if not used remotely. |
| 4 (VREF) | Buffered reference output | Provides stable VDDQ/2 (0.91 V typ) to chipset/DIMMs; remains active during shutdown. |
| 5 (VDDQ) | Reference input rail | Direct connection to DDR memory VDDQ rail (1.8 V); sets VTT target via internal 50k/50k divider. |
| 6 (AVIN) | Analog supply input | Powers internal op-amp and control circuitry; 2.2–5.5 V range decouples analog stability from PVIN noise. |
| 7 (PVIN) | Power output supply | Feeds output stage only; typically tied to 1.8 V memory rail - minimizes dropout and thermal stress. |
| 8 (VTT) | Termination output | Regulated ±500 mA sourcing/sinking node for SSTL-18 bus termination resistors. |
| EP (Exposed Pad) | Thermal ground | Must be soldered to PCB ground plane; primary thermal conduction path for SO PowerPAD-8 package. |
Key Features
| Feature | Design Value |
|---|---|
| No external resistors required | VTT regulation set by internal 50k/50k divider on VDDQ - eliminates calibration drift and BOM count. |
| Suspend-to-RAM (STR) support | VTT tri-states on SD low while VREF stays active - enables memory retention without reference loss. |
| Remote load regulation | VSENSE pin allows feedback from bus center - corrects IR drop across long VTT planes in multi-DIMM systems. |
| Split-rail power architecture | Separate AVIN (2.2–5.5 V) and PVIN (≤ AVIN, typically 1.8 V) inputs - reduces internal power dissipation by >60% vs. single-rail. |
| Thermal robustness | 165°C shutdown with 10°C hysteresis + 43°C/W θJA (SO PowerPAD-8) - sustains 500 mA continuous load at 70°C ambient. |
Applications
| DDR-II Memory Termination | SSTL-18 Bus Interface |
|---|---|
|
Use Scenario: Termination of bidirectional data/address/control lines on DDR-II SDRAM modules in desktop/server motherboards. IC Role / Device Role / Timing Role: Provides dynamically regulated VTT = VDDQ/2 (0.9 V) with ±500 mA sourcing/sinking to meet JEDEC SSTL-18 specifications. Use Value: Ensures signal integrity across high-speed DDR-II buses by maintaining precise termination voltage despite load transients up to ±900 mA. |
Use Scenario: Interface between memory controller and DDR-II DIMMs requiring matched impedance and low-noise reference. IC Role / Device Role / Timing Role: Delivers stable VREF = VDDQ/2 (0.91 V typ) with 2.5 kΩ output impedance to chipset and DIMM reference inputs. Use Value: Eliminates need for external reference buffers; VREF remains active during STR mode to preserve memory state. |
| High-Density Server Memory Subsystem | Low-Power Notebook DDR-II Design |
|
Use Scenario: Multi-rank DDR-II termination in 2U/1U servers where thermal density and board area are constrained. IC Role / Device Role / Timing Role: SO PowerPAD-8 package (θJA = 43°C/W) handles continuous 500 mA load with minimal heatsinking. Use Value: Enables compact, thermally efficient termination without derating - supports dual-channel, quad-rank configurations. |
Use Scenario: Power-optimized DDR-II termination in thin-and-light notebooks requiring STR functionality. IC Role / Device Role / Timing Role: Quiescent current drops from 500 µA to 150 µA in shutdown; VREF stays live for fast resume. Use Value: Reduces system standby power by >70% vs. always-on termination regulators while preserving memory context. |
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; 3-A peak output; requires external compensation; no integrated VREF buffer. | Higher efficiency (>90%) but adds EMI filtering complexity; lacks VREF output - needs separate reference IC. | Choose for high-efficiency, high-current (>500 mA avg) DDR-II systems where thermal budget is tight and EMI can be managed. |
| LP2998MRX/NOPB | Successor device; same SO PowerPAD-8 package; improved VTT accuracy (±15 mV vs. ±25 mV); lower IQ (350 µA vs. 500 µA). | Pin-compatible upgrade path; supports same DDR-II applications with tighter regulation and lower quiescent power. | Choose for new designs requiring enhanced precision and efficiency; LP2997MR remains valid for cost-sensitive legacy refreshes. |
Compared with TPS51100PWR, LP2997MR offers simpler layout, no EMI concerns, and integrated VREF - ideal for noise-sensitive memory interfaces. Compared with LP2998MRX/NOPB, LP2997MR trades minor accuracy and IQ for broader legacy compatibility and established qualification history.
Availability
LP2997MR is available at Aetrix Electronics and suitable for DDR-II memory termination, SSTL-18 bus interface, and low-power Suspend-to-RAM applications requiring stable component supply across industrial, computing, and embedded platforms.
Supply support for LP2997MR 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 and embedded processing technologies, with decades of expertise in power management and high-speed interface solutions.
The LP2997MR belongs to TI's DDR termination regulator product line, engineered specifically to meet JEDEC SSTL-18 requirements for DDR-II memory systems - emphasizing precision, thermal resilience, and seamless integration with memory controllers and DIMMs.
FAQ
What is the exact VTT output voltage tolerance of the LP2997MR over temperature and load?
The LP2997MR maintains VTT = VDDQ/2 with a maximum offset of ±25 mV across the full operating range (0°C to +125°C junction temperature, ±500 mA load). At VDDQ = 1.8 V, VTT is specified as 0.874 V (min) to 0.940 V (max) - meeting JEDEC SSTL-18 termination voltage window requirements. This tolerance includes line, load, and temperature effects per the Electrical Characteristics table in SNVS295F Rev F.
Does the LP2997MR require external resistors to set its output voltage?
No, the LP2997MR does not require external resistors. Its VTT output is internally regulated to VDDQ/2 using a precision-matched 50 kΩ/50 kΩ resistor divider. This eliminates calibration drift, reduces BOM count, and ensures consistent 0.9 V termination for DDR-II when VDDQ = 1.8 V - as confirmed in the Block Diagram and Pin Descriptions sections of the datasheet.
How does the VSENSE pin improve regulation in DDR-II memory systems?
The VSENSE pin enables remote sensing of VTT at the midpoint of the termination bus, compensating for IR drop across long PCB traces. When connected to the center of the VTT plane, it improves load regulation accuracy by >50% compared to local feedback. If unused, VSENSE must still be tied to VTT - as stated in the Pin Descriptions and PCB Layout Considerations sections of SNVS295F.
What happens to VREF and VTT during shutdown (SD = low) on the LP2997MR?
When SD is pulled low, the LP2997MR tri-states VTT (high-impedance) to eliminate termination current, while VREF remains fully active and stable at VDDQ/2. This preserves the reference voltage for memory controller and DIMM inputs during Suspend-to-RAM, enabling fast resume. Quiescent current drops to 150 µA, and thermal shutdown behavior is unchanged - all confirmed in the DESCRIPTION and Pin Descriptions sections.
Is the LP2997MR pin-compatible with the LP2998MRX/NOPB?
Yes, the LP2997MR and LP2998MRX/NOPB share identical SO PowerPAD-8 (DDA) packaging, pinout, and footprint. They are functionally compatible with the same application circuits, though LP2998MRX/NOPB offers tighter VTT accuracy (±15 mV vs. ±25 mV) and lower quiescent current (350 µA vs. 500 µA) - as documented in TI's LP2998 datasheet and PACKAGE OPTION ADDENDUM.
LP2997MR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-PowerSOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- 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
LP2997MR FAQ
1.How can I place an order for LP2997MR through Aetrix?
Please submit a Request for Quotation (RFQ) for LP2997MR 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 LP2997MR reliable?
The price and inventory of LP2997MR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP2997MR is usually 5 days.
3.What payment methods are accepted for LP2997MR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP2997MR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP2997MR?
LP2997MR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP2997MR 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 LP2997MR?
For technical support, including LP2997MR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP2997MR requirements.
6.How does Aetrix verify that LP2997MR is sourced from the original manufacturer or authorized distributors?
All LP2997MR 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 LP2997MR meets industry standards.
7.What is the process for return or replacement of LP2997MR?
All LP2997MR units undergo pre-shipment inspection (PSI). If there is an issue with LP2997MR, 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 LP2997MR part is unused and in its original packaging.
Return procedure for LP2997MR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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