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Analog Devices Inc. LTC3738CUHF#TRPBF
- Part No.:
- LTC3738CUHF#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Special Purpose Regulators
- Package:
- 38-WFQFN Exposed Pad
- Datasheet:
-
LTC3738CUHF#TRPBF.pdf
- Description:
- IC REG CTRLR VRM9 1OUT 38QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,237
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Product details
Overview
LTC3738CUHF#TRPBF from Analog Devices (formerly Linear Technology) is a 3-phase synchronous buck controller designed for Intel VRM9/VRM10-compliant CPU power delivery, featuring active voltage positioning (AVP), true differential remote sensing, and programmable thermal detection. It drives external N-channel MOSFETs across three phases with fixed-frequency PWM, pulse skip, or stage shedding operation, supporting input voltages from 5V to 28V and output voltages from 0.8375V to 1.6000V - used in high-performance notebook computers and server VRMs.
For engineers reviewing the LTC3738CUHF#TRPBF datasheet, LTC3738CUHF#TRPBF pinout, LTC3738CUHF#TRPBF application, or LTC3738CUHF#TRPBF equivalent, this page delivers verified technical context, confirmed pin functions, real-world AVP implementation details, thermal sensing configuration options, and validated alternative controllers for VRM9/VRM10 multi-phase designs.
Technical Context
The LTC3738CUHF#TRPBF implements a constant-frequency, current-mode 3-phase architecture with per-phase oscillator frequency tunable from 210kHz to 530kHz via PLLFLTR voltage (0–2.4V), enabling phase alignment to external clocks. Each phase integrates independent current sensing (SENSE1±–SENSE3±), top/bottom gate drivers (TG1–3, BG1–3), and synchronized soft-start/short-circuit protection.
It supports Intel VRM9/VRM10 VID decoding (6-bit VID0–VID5), differential output voltage sensing (IN+, IN–), and programmable AVP via resistor between AVP and IN+. Internal thermal detection (trip at 120°C, 10°C hysteresis) or external comparator mode (TSNS referenced to VCC/3) is selectable via TSNS pin voltage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology | 3-phase synchronous buck controller driving external N-MOSFETs - enables tripled effective switching frequency for improved transient response and thermal distribution. |
| Input Voltage Range | 5V to 28V - supports standard server/notebook intermediate bus rails including 12V and 19V inputs. |
| Output Voltage Range | 0.8375V to 1.6000V - compliant with Intel VRM9/VRM10 specifications and programmable via 6-bit VID interface. |
| Switching Frequency | 210kHz to 530kHz per phase - adjustable via PLLFLTR pin voltage; supports synchronization to external clock on FCB/SYNC pin. |
| Current Sensing | True differential per-phase sensing (SENSE1±–SENSE3±) with 62–88mV threshold range - enables precise load current matching and AVP slope control. |
| Thermal Protection | Configurable internal (120°C trip, 10°C hysteresis) or external thermal detection via TSNS pin - VR_HOTB open-collector output signals thermal fault. |
| Package | 38-lead 5mm × 7mm QFN (UHF) with exposed SGND pad - optimized for high-current PCB layout and thermal dissipation in dense VRM modules. |
Pinout & Package
38-lead plastic QFN package (5mm × 7mm) with exposed signal ground pad (Pin 39, SGND) requiring solder connection to PCB ground plane for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FCB/SYNC (1) | Mode selection & sync input | Selects forced continuous (V < 0.6V), pulse skip (floating), stage shedding (tied to VCC), or external clock sync - no voltage allowed before VCC applied. |
| PLLFLTR (2) | Oscillator frequency control | DC voltage input (0–2.4V) sets per-phase frequency from 210–530kHz; also serves as PLL low-pass filter node. |
| IN+, IN– (3,4) | Differential output voltage sense | High-precision unity-gain amplifier inputs for true remote sensing of VOUT+ and VOUT– - eliminates ground loop errors in high-current VRM layouts. |
| AVP (5) | Active voltage positioning programming | Resistor-connected node generating load-slope voltage drop (AVP–IN+) - enables dynamic VOUT droop proportional to load current per VRM spec. |
| SENSE1+ to SENSE3– (7–12) | Per-phase current sense inputs | Six dedicated pins (three differential pairs) for Kelvin current sensing at each phase - ensures accurate current matching and foldback protection. |
| SS (13) | Soft-start & short-circuit timer | Capacitor-based ramp controls startup current slew rate; same capacitor triggers timed shutdown if VOUT drops below 62.5% nominal. |
| ITH (14) | Error amplifier output | Common compensation node controlling all three current comparators - defines peak inductor current per phase based on load demand. |
| TSNS (15) | Thermal detection select | Tie to VCC enables internal thermal sensor (120°C); voltage < VCC–1.6V enables external comparator referenced to VCC/3. |
| VR_HOTB (16) | Thermal fault indicator | Open-collector output pulled low during thermal event - compatible with system-level thermal management logic. |
| PGND (24) | Power ground return | Common source node for all bottom MOSFETs and CIN negative terminals - must be low-inductance connection to minimize noise. |
| BG1–BG3 (22–25) | Bottom gate drivers | High-current drivers (0–VCC swing) for N-MOSFET sources - require local 0.1µF decoupling to PGND. |
| VCC (26) | Main supply input | Powers control circuitry and gate drivers - requires tight local decoupling (0.1µF + bulk) to PGND due to high pulsed current demands. |
| SW1–SW3 (21,27,30) | Switch node connections | Connect to inductor high-side nodes - voltage swings from ~–0.4V (Schottky drop) to VIN; critical for layout EMI control. |
| TG1–TG3 (20,28,31) | Top gate drivers | Floating drivers with BOOST-referenced swing - require bootstrapped capacitors between BOOST and SW pins. |
| BOOST1–BOOST3 (19,29,32) | Top driver bootstrap supplies | Accept boot capacitor charge from external Schottky diodes - voltage range: VCC to VCC + VIN (max 38V). |
| PGOOD (33) | Power-good indicator | Open-drain output asserting when VOUT is within ±10% window - blanked for 100µs during VID transitions to avoid false trips. |
| VID0–VID5 (17,18,34–37) | VRM voltage identification inputs | 6-bit digital interface selecting output voltage per Intel VRM9 (VID5 = VCC) or VRM10 (VID5 < VCC–1.5V) tables - includes built-in offset calibration. |
| OUTEN (38) | Enable/disable control | Active-high logic input - pulling low disables all regulation and drivers; rising edge initiates soft-start via SS pin charging. |
| SGND (39) | Signal ground reference | Exposed pad tied to PCB ground plane - mandatory for thermal performance, noise immunity, and stable error amplifier operation. |
Key Features
| Feature | Design Value |
|---|---|
| 3-phase interleaved control | Reduces input/output ripple by factor of ~3 vs single-phase, easing capacitor sizing and improving transient response in CPU VRMs. |
| Programmable Active Voltage Positioning (AVP) | Resistor-programmed load-line slope (AVP–IN+) enables precise VRM9/VRM10-compliant droop without external op-amps or DACs. |
| Differential remote sensing (IN+/IN–) | Eliminates PCB trace IR drop errors and ground loop interference - critical for sub-1V, >100A CPU core rail accuracy. |
| Multi-mode light-load optimization | Stage shedding (10% load), pulse skip (3% load), or forced continuous - selectable via FCB/SYNC pin to maximize efficiency across full load range. |
| Integrated thermal detection | On-chip 120°C thermal sensor with 10°C hysteresis or external comparator mode - reduces BOM count and improves thermal response time. |
| Pre-biased start-up support | Starts into precharged VOUT without sinking current - prevents reverse inductor current during hot-plug or multi-rail sequencing scenarios. |
Applications
| Intel VRM9/VRM10 Notebook CPU Power | Server & Workstation Core VRMs |
|---|---|
|
Use Scenario: High-efficiency, low-noise 3-phase core power delivery for mobile Intel Pentium M/Core Duo processors in thin-and-light notebooks. IC Role / Device Role / Timing Role: Primary 3-phase buck controller managing VID decoding, AVP droop, differential sensing, and phase shedding across three parallel power stages. Use Value: Enables <1.2V output with ±0.5% load regulation and <10mV PGOOD window - meeting strict mobile CPU voltage tolerance specs while minimizing solution size. |
Use Scenario: Scalable multi-phase VRM for dual-socket Xeon servers requiring robust thermal management and fast load-step response. IC Role / Device Role / Timing Role: Centralized 3-phase controller coordinating gate drive timing, current balancing, and thermal fault signaling across distributed power stages. Use Value: Achieves 92% peak efficiency at 20A/1.2V with 120°C thermal shutdown - protecting expensive CPU assets during sustained high-load operation. |
| Desktop PC Motherboard VRMs | High-Performance Embedded Computing |
|
Use Scenario: Cost-optimized VRM on ATX motherboards supporting LGA775/Core 2 Duo CPUs with legacy VRM9 compliance. IC Role / Device Role / Timing Role: Fixed-frequency 3-phase controller implementing VID table lookup, soft-start ramping, and PGOOD sequencing for BIOS handoff. Use Value: Delivers 0.8375–1.6000V output with 0.1% line regulation - ensuring stable boot and overclocking headroom under varying 12V rail conditions. |
Use Scenario: Ruggedized power module for industrial embedded systems (e.g., COM Express modules) requiring long-term supply continuity and thermal resilience. IC Role / Device Role / Timing Role: Mission-critical VRM controller with latch-off short-circuit protection, pre-biased start-up, and -40°C to +85°C ambient operation. Use Value: Maintains regulated output during brownouts and hot-swap events - supported by undervoltage reset (3.3–4.5V) and SS pin arming/latch-off logic. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 3-phase VRM controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ISL6322CRZ-T | 4-phase controller with integrated MOSFET drivers; supports VRM10/11; lacks AVP programming pin - uses internal load-line algorithm. | Targeted at higher-current server platforms (>150A); requires different layout due to 4-phase interleaving and different VID mapping. | Choose ISL6322CRZ-T when scaling beyond 100A or requiring VRM11 compliance; LTC3738CUHF#TRPBF remains optimal for VRM9/VRM10 notebooks with discrete MOSFET flexibility. |
| TPS53355DQPT | 3-phase controller with integrated drivers; supports VRM10/11; includes PMBus interface and telemetry - no AVP pin, uses digital load-line configuration. | Designed for digitally managed power systems; requires MCU-based configuration via SMBus rather than analog resistor programming. | Choose TPS53355DQPT for systems needing real-time telemetry and firmware-configurable load lines; LTC3738CUHF#TRPBF suits analog-centric, cost-sensitive VRM designs. |
Compared with ISL6322CRZ-T and TPS53355DQPT, the LTC3738CUHF#TRPBF offers unique analog AVP programming, differential remote sensing without external amplifiers, and proven compatibility with legacy VRM9 implementations - making it the preferred choice for precision analog VRM designs where layout simplicity and deterministic droop behavior are critical.
Availability
LTC3738CUHF#TRPBF is available at Aetrix Electronics and suitable for high-reliability notebook CPU power, server VRM modules, and desktop motherboard designs requiring stable component supply, long-lifecycle support, and consistent parametric performance across production batches.
Supply support for LTC3738CUHF#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 aerospace, industrial, communications, and computing markets with precision, reliability, and innovation.
The LTC3738CUHF#TRPBF belongs to Linear's VRM controller product line, engineered specifically for Intel-compatible multi-phase CPU core power delivery - emphasizing accuracy, thermal resilience, and seamless integration with existing motherboard power architectures.
FAQ
What is the operating temperature range for the LTC3738CUHF#TRPBF?
The LTC3738CUHF#TRPBF has an operating ambient temperature range of 0°C to 85°C and a maximum junction temperature of 125°C. Its thermal protection features include internal detection (120°C trip, 10°C hysteresis) and configurable external thermal monitoring via the TSNS pin - ensuring safe operation in thermally constrained notebook and server VRM environments where the LTC3738CUHF#TRPBF is commonly deployed.
How does the LTC3738CUHF#TRPBF implement Active Voltage Positioning (AVP)?
The LTC3738CUHF#TRPBF implements AVP using the AVP pin and a resistor network connected between AVP and IN+. This generates a voltage drop (AVP – IN+) proportional to load current, which is added to the output voltage reference to achieve Intel-compliant droop. The LTC3738CUHF#TRPBF's per-phase current sensing and differential amplifier ensure accurate load-line tracking - a key function distinguishing the LTC3738CUHF#TRPBF from non-AVP controllers.
Can the LTC3738CUHF#TRPBF start up into a pre-biased output voltage?
Yes, the LTC3738CUHF#TRPBF supports start-up into precharged VOUT through its dedicated start-up logic: during initial ramp, reverse inductor current is blocked and foldback current limiting is temporarily defeated. This prevents the LTC3738CUHF#TRPBF from sinking current from an already-biased rail - a critical capability for hot-plug systems and multi-rail power sequencing where the LTC3738CUHF#TRPBF is often integrated.
What are the supported VID standards for the LTC3738CUHF#TRPBF?
The LTC3738CUHF#TRPBF supports both Intel VRM9 and VRM10 standards via its 6-bit VID interface (VID0–VID5). VRM9 mode is selected by tying VID5 to VCC; VRM10 mode activates when VID5 voltage falls below VCC – 1.5V. The LTC3738CUHF#TRPBF includes built-in offsets (–12.5mV for VRM9, –25mV for VRM10) and NO_CPU detection with 1µs timeout - ensuring full compatibility with Intel CPU power requirements.
Does the LTC3738CUHF#TRPBF require external components for current sensing?
Yes, the LTC3738CUHF#TRPBF requires external current-sense resistors (RSENSE) placed in series with each phase's low-side MOSFET source path. These resistors feed the SENSE1±–SENSE3± differential inputs, enabling per-phase current measurement. The LTC3738CUHF#TRPBF's internal comparators use these signals - along with the ITH voltage - to set precise peak current thresholds (62–88mV range), making external resistors essential for accurate current matching and AVP functionality.
LTC3738CUHF#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 38-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Applications:
- Controller, Intel VRM9, VRM10
- Voltage - Input:
- 3.8V ~ 36V
- Number of Outputs:
- 1
- Voltage - Output:
- 0.84V ~ 1.6V
- Operating Temperature:
- 0°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 38-QFN (5x7)
LTC3738CUHF#TRPBF FAQ
1.How can I place an order for LTC3738CUHF#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3738CUHF#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 LTC3738CUHF#TRPBF reliable?
The price and inventory of LTC3738CUHF#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3738CUHF#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3738CUHF#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3738CUHF#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3738CUHF#TRPBF?
LTC3738CUHF#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3738CUHF#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 LTC3738CUHF#TRPBF?
For technical support, including LTC3738CUHF#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3738CUHF#TRPBF requirements.
6.How does Aetrix verify that LTC3738CUHF#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3738CUHF#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 LTC3738CUHF#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3738CUHF#TRPBF?
All LTC3738CUHF#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3738CUHF#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 LTC3738CUHF#TRPBF part is unused and in its original packaging.
Return procedure for LTC3738CUHF#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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