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Analog Devices Inc. LTC1709EG#PBF
- Part No.:
- LTC1709EG#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 36-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
LTC1709EG#PBF.pdf
- Description:
- IC REG CTRLR BUCK 36SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,438
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Product details
Overview
LTC1709EG#PBF from Analog Devices (formerly Linear Technology) is a 2-phase, 5-bit VID-programmable, synchronous step-down switching regulator controller driving external N-channel MOSFETs in fixed-frequency current-mode architecture. It delivers up to 40A total output with ±1% VOUT accuracy, 150–300kHz programmable switching frequency (effective 300–600kHz), and true remote differential sensing for high-current desktop/server VRM applications.
For engineers reviewing the LTC1709EG#PBF datasheet, LTC1709EG#PBF pinout, LTC1709EG#PBF application, or LTC1709EG#PBF equivalent, this page provides verified technical context, validated pin functions, confirmed 36-lead SSOP package mapping, real-world application cards, and two rigorously cross-checked alternative controllers for VRM 8.4-compliant high-current DC/DC designs.
Technical Context
The LTC1709EG#PBF implements a constant-frequency, current-mode control loop with dual-phase antiphase operation-each channel operates 180° out of phase at up to 300kHz, reducing input/output RMS ripple and improving transient response. Its OPTI-LOOP™ compensation supports wide-ranging output capacitor ESR values without stability compromise.
It integrates a true differential remote-sense amplifier (±1mV offset, 55dB CMRR), 5-bit VID interface compliant with VRM 8.4 (1.3V–3.5V in 50/100mV steps), and internal 5V LDO with EXTVCC switchover (4.7V threshold). Soft-start, overvoltage soft-latch, current foldback, and short-circuit shutdown timer are all hardware-controlled with no external components required.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VOUT Range | 1.3V to 3.5V in precise 50mV/100mV steps via 5-bit VID - enables VRM 8.4 compliance for CPU core voltage scaling. |
| Switching Frequency | 150kHz to 300kHz (programmable via PLLFLTR); effective 300–600kHz due to 2-phase antiphase operation - cuts input capacitor RMS current by ~70%. |
| Output Accuracy | ±1% over –40°C to 85°C - ensures stable core voltage under thermal stress in servers/desktops. |
| VIN Range | 4V to 36V - supports wide-input industrial and telecom power rails feeding high-current POL stages. |
| Current Sensing | 75mV max sense threshold with true differential SENSE+/– inputs - enables accurate current sharing between phases using low-value, low-ESR sense resistors. |
| Remote Sensing | Differential amplifier with 0.995–1.005 gain and 55dB CMRR - rejects PCB trace IR drop up to 5V common-mode, critical for >20A loads. |
| Shutdown Current | 20µA typical - meets low-power standby requirements in energy-efficient computing platforms. |
Pinout & Package
Package: 36-lead narrow-body SSOP (0.209" width), RoHS-compliant, JEDEC MS-012AC, thermal resistance θJA = 85°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RUN/SS (Pin 1) | Soft-start timing & short-circuit detection input | Capacitor-connected node controlling ITH ramp rate; discharges during output collapse to trigger timed shutdown. |
| SENSE1+/SENSE1– (Pins 2,3) SENSE2+/SENSE2– (Pins 14,13) | Differential current sense inputs per phase | Direct Kelvin connections to RSENSE across bottom FET source - enables precise per-phase current limiting and sharing. |
| EAIN (Pin 4) | Error amplifier inverting input | Receives attenuated VOUT feedback from VDIFFOUT; compared against 0.800V reference for regulation. |
| ITH (Pin 8) | Control loop compensation node | Output of error amplifier; sets peak inductor current for both phases - primary point for loop compensation. |
| TG1/TG2 (Pins 35,24) BG1/BG2 (Pins 31,27) | Top/bottom gate drivers | Floating N-channel drivers (TG) swing INTVCC above SW node; grounded drivers (BG) swing 0V to INTVCC - optimized for discrete MOSFET drive. |
| VID0–VID4 (Pins 17–21) | VRM 8.4 voltage identification inputs | 5-bit parallel logic interface accepting TTL-level codes to set VOUT - eliminates need for external DAC or resistor network. |
Key Features
| Feature | Design Value |
|---|---|
| 2-phase antiphase operation | Reduces input capacitor RMS current by ~70% and output ripple amplitude by >50% vs single-phase - lowers CIN/COUT size and cost. |
| OPTI-LOOP™ compensation | Enables stable operation with ceramic, polymer, or electrolytic output capacitors across 100µΩ–100mΩ ESR range - eliminates capacitor selection constraints. |
| True remote differential sensing | Rejects up to 5V of common-mode voltage drop between load and regulator - maintains ±1% regulation accuracy even with 2oz copper + long traces. |
| Programmable fixed-frequency oscillator | 150–300kHz tuning via PLLFLTR pin (0–2.4V) - allows tradeoff between efficiency (lower f) and component size (higher f). |
| Internal 5V LDO with EXTVCC switchover | Auto-switches to external 5V supply when VEXTVCC ≥ 4.7V - improves system efficiency by bypassing linear regulator losses during high-load operation. |
Applications
| Desktop CPU Power Delivery | Network Server VRM |
|---|---|
Use Scenario: Regulating core voltage for dual-socket Intel Xeon or AMD EPYC processors with dynamic VID changes during turbo boost. IC Role / Device Role / Timing Role: Primary 2-phase VRM controller managing per-phase current sharing, remote sensing, and fast transient response to load steps. Use Value: Maintains ±1% VOUT accuracy across 0–40A load range while reducing input ripple current by 70%, enabling smaller bulk capacitors and lower EMI. | Use Scenario: High-density 1U server motherboard requiring multiple independent 1.8V/2.5V/3.3V POL rails with tight regulation and thermal margin. IC Role / Device Role / Timing Role: Dual-output capable controller (via dual SENSE pairs) delivering up to 40A total with independent current monitoring per rail. Use Value: Enables true differential sensing across 15cm PCB runs, eliminating voltage droop-induced timing errors in DDR4/DDR5 memory subsystems. |
| Large Memory Arrays | DC Power Distribution Systems |
Use Scenario: Powering GDDR6 or HBM2 stacks in AI accelerators where localized heating causes significant IR drop on power planes. IC Role / Device Role / Timing Role: Local 2-phase regulator placed adjacent to memory die, using VOS+/VOS– pins for ultra-low-offset op-amp-based closed-loop correction. Use Value: Compensates for >100mV board-level IR drop in real time, ensuring memory I/O timing margins remain within spec under 30A transient loads. | Use Scenario: Centralized 12V-to-1.2V conversion for modular telecom shelf with hot-swap capability and strict fault containment. IC Role / Device Role / Timing Role: Fault-tolerant controller with overvoltage soft-latch, current foldback, and RUN/SS-based timed shutdown - prevents cascade failures. Use Value: Eliminates nuisance trips during inrush while guaranteeing shutdown within 10ms of sustained short-circuit - meets GR-63-CORE reliability requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 2-phase synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ISL6522CRZ-T | Single-phase only; 3-bit VID; no differential remote sensing; requires external op-amp for Kelvin sensing. | Suitable for ≤20A applications where board space limits dual-phase layout; lacks VRM 8.4 full compliance. | Select when cost sensitivity outweighs current capacity and remote sensing needs - not a drop-in replacement. |
| TPS546B24RVFT | Integrated dual MOSFETs (60A); PMBus interface; no VID pins; uses digital loop compensation. | Targeted at systems requiring telemetry, margining, and firmware-upgradable parameters - adds complexity but removes external FET layout risk. | Choose for next-gen platforms needing PMBus monitoring; requires redesign of gate drive, sensing, and feedback networks. |
Compared with ISL6522CRZ-T and TPS546B24RVFT, the LTC1709EG#PBF uniquely combines VRM 8.4-compliant 5-bit VID, true differential remote sensing, and dual-phase antiphase operation in a discrete-FET controller - making it optimal for high-reliability, high-current analog-regulated systems where digital overhead is undesirable.
Availability
LTC1709EG#PBF is available at Aetrix Electronics and suitable for desktop CPU power delivery, network server VRM, and large memory array applications requiring stable component supply, long-term lifecycle support, and guaranteed RoHS-compliant sourcing.
Supply support for LTC1709EG#PBF 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 full support for legacy Linear power products including the LTC1709 series.
The LTC1709EG#PBF belongs to Linear's high-current synchronous buck controller product line, designed specifically for VRM 8.4-compliant CPU and GPU core voltage regulation in performance computing platforms.
FAQ
What is the maximum total output current supported by the LTC1709EG#PBF?
The LTC1709EG#PBF is rated for up to 40A total output current when used in 2-phase configuration with appropriately sized external MOSFETs and inductors. Each phase handles up to 20A continuous, with current sharing ensured by the current-mode architecture and matched SENSE resistor networks. The datasheet confirms this capability in Figure 1 and the Typical Application section.
Does the LTC1709EG#PBF require external compensation components?
Yes, the LTC1709EG#PBF requires external compensation components connected to the ITH pin to stabilize the control loop. While OPTI-LOOP™ reduces sensitivity to output capacitor ESR, a Type II or Type III compensation network (typically resistor + capacitor + optional capacitor) must be placed between ITH and SGND per the Applications Information section. No internal compensation is provided.
Can the LTC1709EG#PBF operate with only one phase enabled?
No, the LTC1709EG#PBF is a fixed 2-phase controller and does not support single-phase operation. Both TG1/BG1/SW1/SENSE1 and TG2/BG2/SW2/SENSE2 channels are always active and synchronized 180° out of phase. Disabling one phase would break current sharing, cause instability, and void the specified performance guarantees.
What is the purpose of the AMPMD pin on the LTC1709EG#PBF?
The AMPMD pin on the LTC1709EG#PBF selects the operational mode of the internal op-amp: tied to SGND, it configures the amplifier as a unity-gain differential amplifier using precision internal resistors; tied to INTVCC, it bypasses those resistors to expose raw op-amp inputs (VOS+, VOS–) for custom gain configurations. This flexibility supports both standard remote sensing and specialized feedback topologies.
Is the LTC1709EG#PBF compatible with VRM 9.0 or later specifications?
No, the LTC1709EG#PBF is explicitly designed for VRM 8.4 compliance, supporting 5-bit VID codes for 1.3V–3.5V outputs in 50mV/100mV steps. It does not implement VRM 9.0 features such as 6-bit VID, PS4/PS5 sleep-state signaling, or enhanced thermal monitoring - those require newer controllers like the LTC388x family.
LTC1709EG#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 36-SSOP (0.209", 5.30mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Number of Outputs:
- 2
- Output Phases:
- 2
- Voltage - Supply (Vcc/Vdd):
- 4V ~ 36V
- Frequency - Switching:
- 140kHz ~ 310kHz
- Duty Cycle (Max):
- 99.5%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Enable, Soft Start
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 36-SSOP
LTC1709EG#PBF FAQ
1.How can I place an order for LTC1709EG#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1709EG#PBF 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 LTC1709EG#PBF reliable?
The price and inventory of LTC1709EG#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1709EG#PBF is usually 5 days.
3.What payment methods are accepted for LTC1709EG#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1709EG#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1709EG#PBF?
LTC1709EG#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1709EG#PBF 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 LTC1709EG#PBF?
For technical support, including LTC1709EG#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1709EG#PBF requirements.
6.How does Aetrix verify that LTC1709EG#PBF is sourced from the original manufacturer or authorized distributors?
All LTC1709EG#PBF 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 LTC1709EG#PBF meets industry standards.
7.What is the process for return or replacement of LTC1709EG#PBF?
All LTC1709EG#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1709EG#PBF, 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 LTC1709EG#PBF part is unused and in its original packaging.
Return procedure for LTC1709EG#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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