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Analog Devices Inc. LTC3617IUDD#TRPBF
- Part No.:
- LTC3617IUDD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Special Purpose Regulators
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LTC3617IUDD#TRPBF.pdf
- Description:
- IC REG CONV DDR 1OUT 24QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,390
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Product details
Overview
LTC3617IUDD#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 with ±10mA sourcing/sinking capability for DDR1/2/3 compliance.
For engineers reviewing the LTC3617IUDD#TRPBF datasheet, LTC3617IUDD#TRPBF pinout, LTC3617IUDD#TRPBF application, or LTC3617IUDD#TRPBF equivalent, key selection criteria include bidirectional current capability, VDDQIN-tracking accuracy (±10mV), forced continuous mode for noise-sensitive systems, external frequency programming via RT pin, and thermal performance in the 3mm × 5mm QFN-24 package with exposed PGND pad.
Technical Context
The LTC3617IUDD#TRPBF employs constant-frequency current-mode control with integrated P-channel high-side and N-channel low-side MOSFETs (RDS(ON) = 35mΩ / 25mΩ at 3.3V). Its error amplifier uses VTTR - derived from VDDQIN × 0.5 - as reference, enabling precise tracking of DDR supply rails while supporting ±6A load current with ±10mA VTTR buffer current.
It features dual protection architecture: input overvoltage lockout at 6.5V and short-circuit protection with asymmetric peak current limits (+10A sourcing / –8A sinking). The ITH pin enables adjustable compensation, and synchronization via SYNC pin supports external clock locking from 300kHz to 4MHz without phase shift.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | ±6A continuous sourcing/sinking - enables active DDR termination with dynamic voltage tracking |
| Input Voltage Range | 2.25V to 5.5V - supports wide-range DDR memory supply inputs including 2.5V, 3.3V, and 5V rails |
| Output Voltage Accuracy | ±10mV - ensures tight VTTR regulation critical for DDR signal integrity and JEDEC compliance |
| Switching Frequency | Up to 4MHz programmable - allows use of sub-μH inductors (e.g., 0.15μH) to minimize board area |
| Efficiency | 90% at 6A, VIN=3.3V, VOUT=1.25V - achieved via synchronous rectification eliminating external catch diode |
| Shutdown Current | <1µA - enables ultra-low-power system standby states without compromising fast wake-up |
| Thermal Resistance θJA | 43°C/W - validated in 3mm × 5mm QFN-24 with soldered exposed PGND pad for high-power density designs |
Pinout & Package
Package: 24-pin 3mm × 5mm thermally enhanced QFN with exposed PGND pad (Pin 25), rated for –40°C to +125°C junction temperature.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RT (Pin 1) | Oscillator frequency control | Resistor-to-ground sets fSW from 300kHz–4MHz; tie to SVIN for internal 2.25MHz default |
| VTTR (Pin 3) | VDDQIN × 0.5 buffered output | Provides ±10mA tracking reference for DDR termination; max 0.1µF bypass capacitance |
| PVIN (Pins 4,10,11,17) | High-side MOSFET source supply | Independent power rail for top switch; may be lower than SVIN to reduce conduction loss |
| SW (Pins 5,6,7,8,13,14,15,16) | Power switch node | Eight paralleled pins reduce trace inductance and thermal resistance for ±6A switching currents |
| PGND (Pin 25, Exposed Pad) | Power ground return | Mandatory PCB solder connection; serves as N-MOSFET source and primary thermal path |
| VDDQIN (Pin 24) | Tracking reference input | Sets both VTTR and VFB reference; determines regulated output voltage (VOUT = 0.5 × VDDQIN) |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional ±6A output | Enables true active DDR termination that sinks current during bus idle and sources during data transitions |
| Integrated VTTR buffer | Eliminates need for external op-amp circuitry while maintaining ±10mV accuracy across temperature and load |
| Forced continuous conduction mode | Prevents subharmonic oscillation and reduces EMI in noise-sensitive applications like RF subsystems |
| Programmable soft-start | Internal 0.85ms typical ramp (VFB 0.075V → 0.675V) prevents inrush current and ensures controlled power-up sequencing |
| Input overvoltage protection | Automatic shutdown at 6.5V on PVIN/SVIN prevents damage from transient spikes on DDR supply rails |
Applications
| DDR Memory Termination | DDR2/DDR3 Tracking Supply |
|---|---|
Use Scenario: Termination of high-speed DDR memory data/strobe lines in server DIMMs and embedded controllers. IC Role / Device Role / Timing Role: Active termination regulator providing real-time bidirectional current to maintain stable VTT voltage during read/write cycles. Use Value: Maintains signal integrity at >800MT/s by dynamically matching line impedance without passive resistor networks. |
Use Scenario: Generating matched VTT and VTTR supplies for DDR2/DDR3 memory interfaces requiring precise 0.5×VDDQIN tracking. IC Role / Device Role / Timing Role: Dual-function regulator delivering synchronized termination voltage and reference buffer for memory controller I/O banks. Use Value: Achieves ±10mV tracking accuracy across –40°C to +125°C, meeting JEDEC JESD79-2E specification. |
| Low-Voltage Tracking Regulator | High-Efficiency Point-of-Load Converter |
Use Scenario: Powering FPGA I/O banks or ASIC core logic requiring tightly regulated low-voltage rails derived from a master supply. IC Role / Device Role / Timing Role: Precision tracking regulator using VDDQIN as master reference to generate dependent sub-1.5V outputs. Use Value: Enables single-supply system architectures with <1% tracking error, reducing BOM count and layout complexity. |
Use Scenario: High-current POL conversion in telecom baseband cards and industrial PLCs where space and thermal constraints are critical. IC Role / Device Role / Timing Role: Monolithic buck converter delivering up to 6A with integrated MOSFETs and 43°C/W thermal resistance. Use Value: Eliminates external high-side FET and catch diode, reducing component count by ≥4 while maintaining >90% efficiency at full load. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar DDR termination regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS51200DRCT | Fixed 2MHz frequency; ±3A output; no external RT programming; requires external VTTR buffer | Limited to DDR2/DDR3 with lower current headroom; lacks ±6A bidirectional capability | Select when cost sensitivity outweighs need for programmable frequency and higher current margin |
| ISL95812IRZ-T | Supports DDR4; ±8A output; 3.3V-only input range; no VDDQIN tracking - uses internal reference | Targeted for DDR4 LRDIMMs; incompatible with legacy DDR/DDR2/DDR3 VDDQIN-based tracking schemes | Select only for new DDR4 designs requiring >6A and JEDEC DDR4 compliance |
Compared with TPS51200DRCT and ISL95812IRZ-T, the LTC3617IUDD#TRPBF uniquely combines VDDQIN-based tracking, ±6A bidirectional operation, and full 2.25V–5.5V input flexibility - making it the only option supporting DDR1 through DDR3 with field-programmable frequency and minimal external components.
Availability
LTC3617IUDD#TRPBF is available at Aetrix Electronics and suitable for DDR memory termination, high-density point-of-load conversion, and FPGA I/O supply applications requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LTC3617IUDD#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 and maintains its high-performance power management portfolio with rigorous automotive and industrial qualification standards.
The LTC3617IUDD#TRPBF belongs to Linear's precision monolithic DC/DC regulator family, designed specifically for memory interface power delivery where bidirectional current, tight tracking, and low-noise operation are mandatory.
FAQ
What is the maximum allowable capacitance on the VTTR pin of the LTC3617IUDD#TRPBF?
The LTC3617IUDD#TRPBF datasheet specifies a hard limit of 0.1µF maximum capacitance on the VTTR pin to ensure stability of the internal voltage buffer. Exceeding this value risks oscillation or degraded transient response due to phase margin reduction in the buffer's feedback loop. This constraint applies regardless of capacitor type or voltage rating, and must be verified during layout using manufacturer-recommended placement near Pin 3 with short traces to SGND.
Does the LTC3617IUDD#TRPBF support forced continuous conduction mode (FCCM) across its full operating range?
Yes, the LTC3617IUDD#TRPBF supports forced continuous conduction mode at all input voltages (2.25V–5.5V), load currents (±6A), and switching frequencies (300kHz–4MHz). FCCM is enabled by default and eliminates mode transitions that cause audible noise and output voltage ripple - critical for DDR termination where consistent current sourcing/sinking is required during both active and idle bus states.
How does the LTC3617IUDD#TRPBF achieve ±10mV output voltage accuracy?
The LTC3617IUDD#TRPBF achieves ±10mV accuracy through a combination of trimmed internal resistive dividers, matched MOSFET RDS(ON) tracking, and VTTR-based feedback architecture. The VFB pin regulates directly to VTTR (0.5 × VDDQIN), and the ±10mV spec includes initial tolerance, line regulation (0.2%/V), and load regulation (0.25%) over the full –40°C to +125°C temperature range - verified per JEDEC JESD47 reliability testing.
Can the LTC3617IUDD#TRPBF be synchronized to an external clock while operating at 4MHz?
Yes, the LTC3617IUDD#TRPBF supports synchronization to external clocks from 300kHz to 4MHz inclusive. When the SYNC pin receives a clean square wave within this range, the internal oscillator locks to the falling edge of the input clock. At 4MHz, proper layout - including short trace length, local 0.1µF decoupling on SVIN, and avoidance of noisy digital signals near SYNC - is essential to maintain jitter below 150ps RMS.
What is the purpose of the eight paralleled SW pins on the LTC3617IUDD#TRPBF?
The eight paralleled SW pins (Pins 5,6,7,8,13,14,15,16) on the LTC3617IUDD#TRPBF reduce effective bond wire and trace inductance for high di/dt switching events, minimize voltage overshoot during turn-off, and distribute thermal load across the QFN package. This configuration supports the ±6A bidirectional current requirement while maintaining <10mV switching node ringing under worst-case load transients - a necessity for DDR signal integrity.
LTC3617IUDD#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)
LTC3617IUDD#TRPBF FAQ
1.How can I place an order for LTC3617IUDD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3617IUDD#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 LTC3617IUDD#TRPBF reliable?
The price and inventory of LTC3617IUDD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3617IUDD#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3617IUDD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3617IUDD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3617IUDD#TRPBF?
LTC3617IUDD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3617IUDD#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 LTC3617IUDD#TRPBF?
For technical support, including LTC3617IUDD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3617IUDD#TRPBF requirements.
6.How does Aetrix verify that LTC3617IUDD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3617IUDD#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 LTC3617IUDD#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3617IUDD#TRPBF?
All LTC3617IUDD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3617IUDD#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 LTC3617IUDD#TRPBF part is unused and in its original packaging.
Return procedure for LTC3617IUDD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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