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Analog Devices Inc. LTC3617EUDD#TRPBF
- Part No.:
- LTC3617EUDD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Special Purpose Regulators
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LTC3617EUDD#TRPBF.pdf
- Description:
- IC REG CONV DDR 1OUT 24QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,473
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Product details
Overview
LTC3617EUDD#TRPBF from Analog Devices (formerly Linear Technology) is a monolithic synchronous step-down DC/DC regulator optimized for DDR memory termination, delivering ±6A bidirectional output current with 0.5 × VDDQIN tracking. It operates from 2.25V to 5.5V input, supports up to 4MHz switching frequency, and integrates VTTR buffering (±10mA) and power-good monitoring. Used in DDR/DDR2/DDR3 memory subsystems requiring precise low-voltage tracking and high-current sink/source capability.
For engineers reviewing the LTC3617EUDD#TRPBF datasheet, LTC3617EUDD#TRPBF pinout, LTC3617EUDD#TRPBF application, or LTC3617EUDD#TRPBF equivalent, key selection criteria include its ±6A bidirectional output, 0.5×VDDQIN VTTR tracking accuracy (±10mV), thermally enhanced 24-pin 3mm × 5mm QFN package, forced continuous mode for noise-sensitive systems, and external synchronization support up to 4MHz.
Technical Context
The LTC3617EUDD#TRPBF employs constant-frequency current-mode control with internal P-channel and N-channel MOSFETs (RDS(ON) = 35mΩ / 25mΩ at 3.3V), enabling high-efficiency regulation down to 0.5V output. Its error amplifier uses VTTR as reference, and ITH pin enables adjustable external compensation for transient optimization across wide load/capacitor ranges.
It features dual protection architecture: input overvoltage lockout (6.5V threshold) and dual current limiting-+10A peak sourcing and –8A peak sinking-with reverse-current detection. The device supports three frequency-setting methods: RT-to-ground resistor, RT tied to SVIN (2.25MHz default), or SYNC pin synchronization (300kHz–4MHz).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | ±6A continuous bidirectional delivery - supports DDR termination with simultaneous sourcing and sinking during memory read/write transitions. |
| Input Voltage Range | 2.25V to 5.5V - enables direct operation from common system rails (e.g., 3.3V, 5V) without pre-regulation. |
| VTTR Accuracy | ±10mV over temperature - ensures tight tracking of half-VDDQIN for DDR compliance (e.g., 0.75V ±10mV when VDDQIN = 1.5V). |
| Switching Frequency | Up to 4MHz programmable - allows use of sub-μH inductors (e.g., 0.15µH–0.33µH) and reduces solution footprint. |
| Shutdown Current | <1µA - minimizes standby power loss in memory subsystems during deep sleep modes. |
| Thermal Package | 24-pin 3mm × 5mm QFN with exposed PGND pad (θJA = 43°C/W) - enables high-power density layout with direct PCB thermal coupling. |
| Power Good Window | ±8% output voltage tolerance with 105µs blanking - provides reliable rail validation for DDR controller sequencing. |
Pinout & Package
Package: 24-pin, 3mm × 5mm, leadless QFN with exposed thermal pad (Pin 25 = PGND). RoHS-compliant, tape-and-reel packaged (LTC3617EUDD#TRPBF).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RT (1) | Oscillator frequency control | Resistor-to-ground sets fSW (300kHz–4MHz); tie to SVIN for 2.25MHz internal clock - critical for EMI tuning and inductor sizing. |
| SGND (2) | Signal ground reference | Reference point for feedback, compensation, and small-signal circuitry - must connect to PGND at single point to avoid noise coupling. |
| VTTR (3) | Voltage tracking buffer output | Provides 0.5 × VDDQIN with ±10mA drive - directly supplies DDR VTTR rail; bypass ≤0.1µF required for stability. |
| PVIN (4,10,11,17) | Power MOSFET source supply | Connects to P-channel switch source - may be same as VIN or lower voltage to reduce conduction loss. |
| SW (5,6,7,8,13,14,15,16) | Switch node | Drain connection of internal MOSFETs - ties to inductor; multiple pins reduce parasitic inductance and improve thermal spreading. |
| RUN (19) | Enable control input | Active-high logic input - drives regulator into <1µA shutdown state when pulled low; supports power sequencing. |
| SYNC (20) | External clock input | Accepts 300kHz–4MHz square wave - synchronizes switching edge to system clock to suppress beat frequencies in noise-critical applications. |
| PGOOD (21) | Open-drain status output | Asserts high when VFB is within ±8% window for >105µs - used for DDR controller reset or power sequencing coordination. |
| VFB (22) | Feedback voltage input | Senses output via resistive divider - regulates to VTTR (0.5 × VDDQIN); accuracy directly determines DDR termination voltage precision. |
| ITH (23) | Error amplifier compensation node | Controls current limit threshold and loop dynamics - external RC/CC network optimizes transient response for specific COUT and load conditions. |
| VDDQIN (24) | Reference input voltage | Sets VTTR and VFB reference - typically DDR QVDD rail (1.5V/1.35V/1.2V); accuracy propagates directly to output tracking. |
| PGND (25, Exposed Pad) | Power ground return | Source connection for N-channel switch - must be soldered to large PCB copper area for thermal and EMI performance. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional ±6A output | Enables true DDR termination with simultaneous sourcing (read) and sinking (write), eliminating need for separate LDO + sink circuit. |
| Integrated VTTR buffer | Delivers 0.5 × VDDQIN with ±10mA and ±10mV accuracy - meets JEDEC DDR2/DDR3 VTTR tolerance requirements without external op-amp. |
| Forced continuous conduction mode | Eliminates discontinuous-mode subharmonics - reduces conducted EMI and improves transient response predictability in memory interfaces. |
| Input overvoltage protection | Shuts down both MOSFETs if PVIN exceeds 6.5V - protects internal switches during hot-swap or supply transients in server/desktop platforms. |
| Adjustable soft-start | Internal 0.85ms typical ramp (VFB 0.075V → 0.675V) - prevents inrush current and ensures controlled DDR rail ramp-up during power-on. |
Applications
| DDR Memory Termination | DDR2/DDR3 VTT Supply |
|---|---|
|
Use Scenario: Providing matched termination voltage (VTT) for DDR SDRAM data/address buses in servers, workstations, and networking equipment. IC Role / Device Role / Timing Role: Regulates VTT to exactly 0.5 × VDDQIN while sourcing/sinking up to ±6A during fast data transitions. Use Value: Maintains signal integrity by minimizing reflections and ensuring stable bus voltage under dynamic load, directly supporting DDR2/DDR3 timing margins. |
Use Scenario: Generating compliant VTTR rail for DDR2/DDR3 memory controllers in FPGA-based accelerators and telecom baseband cards. IC Role / Device Role / Timing Role: Acts as dedicated tracking regulator with integrated buffer, referenced to memory I/O supply (VDDQIN). Use Value: Achieves ±10mV VTTR accuracy over temperature - satisfies JEDEC JESD79-2E/JESD79-3F specification for DDR2/DDR3 VTTR tolerance. |
| Memory Subsystem Tracking | Low-Voltage Bidirectional Rail |
|
Use Scenario: Coordinating VTT and VREF rails in multi-rank DDR modules where VDDQIN varies dynamically with memory speed states. IC Role / Device Role / Timing Role: Tracks real-time VDDQIN changes and updates VTTR proportionally with minimal delay (<100ns propagation). Use Value: Enables adaptive memory power management without compromising signal fidelity during frequency scaling or partial-array activation. |
Use Scenario: Powering high-speed interface termination (e.g., LVDS, SSTL) requiring precise low-voltage (≤1.25V), bidirectional current capability. IC Role / Device Role / Timing Role: Functions as a programmable ±6A current-source/sink with 0.5V minimum output - replaces discrete FET + op-amp solutions. Use Value: Reduces BOM count by 7+ components and board area by >40% versus discrete bidirectional regulator implementations. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar DDR termination regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS51200DRCR | Fixed 0.5×VDDQIN tracking; ±3A output; no SYNC input; 1.5MHz fixed frequency | Limited to ≤3A DDR1/DDR2 applications; lacks programmable frequency and external sync for EMI control | Select when cost sensitivity outweighs need for >3A current or EMI tuning flexibility. |
| ISL95831IRZ | ±6A output; supports DDR3/DDR3L; includes telemetry (I2C); 3mm × 3mm 16-pin QFN | Requires external VTTR buffer; no integrated VTTR output; smaller package limits thermal headroom at full load | Prefer when digital telemetry and compact size are prioritized over integrated VTTR simplicity and thermal robustness. |
Compared with TPS51200DRCR and ISL95831IRZ, the LTC3617EUDD#TRPBF uniquely combines ±6A bidirectional current, integrated ±10mA VTTR buffer, 4MHz programmability, and SYNC capability - making it optimal for high-performance DDR3/DDR4 termination where precision, noise control, and thermal margin are critical.
Availability
LTC3617EUDD#TRPBF is available at Aetrix Electronics and suitable for DDR memory termination, server memory subsystems, and FPGA-based high-speed interface designs requiring stable component supply and long-term industrial availability.
Supply support for LTC3617EUDD#TRPBF 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
Analog Devices (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management ICs, serving industrial, automotive, communications, and computing markets.
The LTC3617EUDD#TRPBF belongs to Linear's high-current monolithic DC/DC regulator product line, designed specifically for DDR memory power delivery with integrated tracking, bidirectional current, and robust protection - targeting enterprise and infrastructure applications demanding reliability and JEDEC compliance.
FAQ
What is the primary function of the LTC3617EUDD#TRPBF in DDR memory systems?
The LTC3617EUDD#TRPBF serves as a monolithic ±6A bidirectional synchronous buck regulator that generates and regulates the VTTR termination voltage equal to 0.5 × VDDQIN for DDR, DDR2, and DDR3 memory interfaces. Its integrated VTTR buffer, ±10mV accuracy, and ability to source/sink current simultaneously ensure JEDEC-compliant signal integrity during high-speed data transitions. The LTC3617EUDD#TRPBF eliminates discrete solutions while maintaining tight tracking under dynamic load conditions.
How does the LTC3617EUDD#TRPBF achieve ±6A bidirectional current capability?
The LTC3617EUDD#TRPBF achieves ±6A bidirectional operation using internal synchronous P-channel (top) and N-channel (bottom) MOSFETs with RDS(ON) of 35mΩ and 25mΩ respectively. During sourcing, the top switch delivers current to the load; during sinking, the bottom switch conducts current from the load to ground. Peak current limits are set at +10A (sourcing) and –8A (sinking), enabling sustained ±6A delivery with thermal management via its exposed-pad QFN package. The LTC3617EUDD#TRPBF maintains regulation through current-mode control and VTTR-referenced feedback.
Can the LTC3617EUDD#TRPBF be synchronized to an external clock, and what is the supported range?
Yes, the LTC3617EUDD#TRPBF supports external synchronization via its SYNC pin, accepting square-wave clock signals from 300kHz to 4MHz. This feature allows alignment of switching edges with system clocks to suppress beat frequencies and reduce EMI in noise-sensitive applications like high-speed memory channels. When synchronized, the top switch turn-on is locked to the falling edge of the external clock. The LTC3617EUDD#TRPBF maintains full regulation and protection functionality during synchronization, and the internal oscillator automatically adjusts when SYNC is enabled or disabled.
What is the role of the VDDQIN pin on the LTC3617EUDD#TRPBF, and how does it affect output voltage?
The VDDQIN pin on the LTC3617EUDD#TRPBF provides the reference voltage for both the VTTR buffer and the feedback loop. The LTC3617EUDD#TRPBF internally generates VTTR = 0.5 × VDDQIN and regulates VOUT to match VTTR, resulting in VOUT = 0.5 × VDDQIN. This direct proportional relationship ensures automatic tracking as VDDQIN changes (e.g., during DDR speed-state transitions). For example, if VDDQIN = 1.5V, both VTTR and VOUT settle at 0.75V ±10mV. The LTC3617EUDD#TRPBF requires VDDQIN to be stable and within 2.25V–5.5V for proper operation.
Does the LTC3617EUDD#TRPBF include overvoltage protection, and how does it behave?
Yes, the LTC3617EUDD#TRPBF includes input overvoltage protection that monitors PVIN and SVIN. If either exceeds 6.5V, the device suspends switching by turning off both internal MOSFETs to prevent damage. After the overvoltage condition clears, the LTC3617EUDD#TRPBF executes its internal soft-start sequence before resuming regulation. This protection operates independently of RUN pin state and remains active in all operating modes. The LTC3617EUDD#TRPBF also features undervoltage lockout (1.7V/2.2V thresholds) and thermal shutdown to ensure robust operation in demanding environments.
LTC3617EUDD#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 24-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Applications:
- Converter, DDR
- Voltage - Input:
- 2.25V ~ 5.5V
- Number of Outputs:
- 1
- Voltage - Output:
- Adj to 0.5V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-QFN (3x5)
LTC3617EUDD#TRPBF FAQ
1.How can I place an order for LTC3617EUDD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3617EUDD#TRPBF 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 LTC3617EUDD#TRPBF reliable?
The price and inventory of LTC3617EUDD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3617EUDD#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3617EUDD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3617EUDD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3617EUDD#TRPBF?
LTC3617EUDD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3617EUDD#TRPBF 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 LTC3617EUDD#TRPBF?
For technical support, including LTC3617EUDD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3617EUDD#TRPBF requirements.
6.How does Aetrix verify that LTC3617EUDD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3617EUDD#TRPBF 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 LTC3617EUDD#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3617EUDD#TRPBF?
All LTC3617EUDD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3617EUDD#TRPBF, 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 LTC3617EUDD#TRPBF part is unused and in its original packaging.
Return procedure for LTC3617EUDD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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