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Analog Devices Inc. LTC3838IUHF-1#PBF
- Part No.:
- LTC3838IUHF-1#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 38-WFQFN Exposed Pad
- Datasheet:
-
LTC3838IUHF-1#PBF.pdf
- Description:
- IC REG CTRLR BUCK 38QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,731
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Product details
Overview
LTC3838IUHF-1#PBF from Analog Devices (formerly Linear Technology) is a dual-channel, PolyPhase® synchronous step-down DC/DC controller driving all-N-channel MOSFETs. It delivers ±0.67% and ±0.75% differential output regulation on Channels 1 and 2 respectively, supports 4.5V–38V input, 0.6V–5.5V output, and features controlled on-time valley current mode control with 30ns minimum on-time for high step-down ratio applications in ASIC power supplies.
For engineers reviewing the LTC3838IUHF-1#PBF datasheet, LTC3838IUHF-1#PBF pinout, LTC3838IUHF-1#PBF application, or LTC3838IUHF-1#PBF equivalent, key selection criteria include dual differential remote sensing (±500mV/±200mV ground deviation tolerance), DTR-enabled load-release transient suppression, programmable 200kHz–2MHz switching frequency, and thermally enhanced 38-pin QFN package with exposed PGND pad.
Technical Context
The LTC3838IUHF-1#PBF implements a controlled on-time, valley current mode architecture enabling fast transient response without clock delay while maintaining constant-frequency operation at steady state. Its proprietary Detect Transient Release (DTR) circuitry actively reduces output overshoot during rapid load release by dynamically disabling the bottom gate driver when the DTR pin voltage drops below half of INTVCC.
Dual independent error amplifiers (ITH1/ITH2) support either two regulated outputs or multiphase single-output configuration via VOUTSENSE1+ shorting to INTVCC. Channel phase alignment (0°/180°/240°) and CLKOUT synchronization are controlled via PHASMD and MODE/PLLIN pins, with internal 600kΩ pull-down on MODE/PLLIN for default discontinuous mode operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 38V - supports wide-input industrial, telecom, and distributed power systems without pre-regulation |
| Output Regulation Accuracy | ±0.67% (Ch1), ±0.75% (Ch2) over temperature - enables tight-tolerance core voltage regulation for FPGAs and ASICs |
| Switching Frequency Range | 200kHz to 2MHz - adjustable via RT resistor or external clock sync for EMI optimization and size reduction |
| Min On/Off Time | tON(MIN) = 30ns, tOFF(MIN) = 90ns - allows near 0% and near 100% duty cycles for ultra-low VOUT (e.g., 0.6V) at high VIN |
| Differential Sensing Range | ±500mV (Ch1), ±200mV (Ch2) - compensates PCB trace IR drop for accurate remote load point regulation |
| Current Sense Options | RSENSE or inductor DCR sensing - eliminates need for dedicated sense resistors, reducing power loss and BOM cost |
| Thermal Rating | –40°C to +125°C junction - qualified for industrial and automotive under-hood environments |
Pinout & Package
Package: 38-lead (5mm × 7mm) plastic QFN with exposed PGND pad (Pin 39), requiring soldering to PCB for thermal and electrical performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDFB2+ (1) | Channel 2 differential feedback (+) input | Connects to 3-resistor divider for precise 0.6V × (RFB1+RFB2)/RFB1 regulation of VOUT2 |
| VRNG (2) | Current sense range select | SGND = 30mV max sense voltage; INTVCC = 60mV - sets current limit accuracy and noise immunity |
| MODE/PLLIN (5) | Mode control / external clock input | INTVCC = forced continuous mode; SGND = discontinuous mode; external clock = sync source |
| CLKOUT (6) | Internal clock output | Provides synchronized clock signal (phase set by PHASMD) for multi-controller coordination |
| PHASMD (9) | Phase configuration input | SGND = 180° channel offset; FLOAT = 180°/90°; INTVCC = 240°/120° - enables interleaved multiphase operation |
| VOUTSENSE1+ (12) | Channel 1 differential sense (+) | Connected across output capacitor to regulate VOUT1 differentially; short to INTVCC enables dual-phase single-output mode |
| DTR1 (16) | Load-release transient detector | Internal 2.5µA pull-up; falling below 0.5×INTVCC triggers BG1 disable to minimize overshoot |
| RUN1 (17) | Channel 1 enable control | 1.2V threshold with 100mV hysteresis; PTAT pull-up enables independent channel sequencing |
| PGOOD1 (18) | Channel 1 power-good indicator | Open-drain output asserting low if VFB1 deviates >±7.5% for >50µs - used for system power sequencing |
| TG1 (20) | Top gate driver output | Drives N-channel MOSFET gate with 2.5Ω pull-up / 1.2Ω pull-down; supports bootstrap operation up to 46V |
Key Features
| Feature | Design Value |
|---|---|
| Dual differential remote sensing | Enables ±500mV common-mode rejection on Ch1 and ±200mV on Ch2 to maintain regulation accuracy despite PCB ground bounce |
| Detect Transient Release (DTR) | Reduces output overshoot by up to 50% during 15A→0A load release, verified in Figure G07/G08 waveforms |
| Controlled on-time valley current mode | Delivers sub-100ns transient response without clock latency while preserving constant-frequency operation at light loads |
| Programmable multiphase timing | Supports 0°/180°/240° channel phasing and CLKOUT synchronization for optimal ripple cancellation and thermal distribution |
| Flexible current sensing | Accepts RSENSE (Kelvin-connected) or inductor DCR with integrated 500kΩ SENSE– bias resistors - eliminates external components |
Applications
| ASIC Core Power Supply | High-Density Server VRM |
|---|---|
Use Scenario: Providing tightly regulated 0.6V–1.2V core voltage to multi-core processors and FPGAs with dynamic current demands up to 15A per rail. IC Role / Device Role / Timing Role: Dual-channel synchronous buck controller implementing differential remote sensing and DTR to suppress load-step-induced overshoot/undershoot. Use Value: Achieves ±0.67% regulation accuracy and <5µs transient recovery time, meeting Intel VR13/VR14 specifications for CPU core rails. | Use Scenario: Generating multiple independent voltages (e.g., 1.2V I/O, 0.85V memory) from a 12V intermediate bus in 1U rack servers. IC Role / Device Role / Timing Role: Dual-output controller operating in independent mode with separate TRACK/SS pins for coordinated power-up sequencing. Use Value: Eliminates need for external sequencing ICs via programmable soft-start ramp rates and PGOOD monitoring per channel. |
| Multiphase GPU Power Delivery | Industrial FPGA Power System |
Use Scenario: Delivering >30A at 0.9V to graphics processing units using two LTC3838IUHF-1#PBF controllers in interleaved 4-phase configuration. IC Role / Device Role / Timing Role: Phase-synchronized controller pair with PHASMD and CLKOUT signals ensuring 90° channel offset for ripple cancellation. Use Value: Reduces output capacitor RMS current by 30% and thermal stress on MOSFETs compared to single-phase designs. | Use Scenario: Powering Xilinx Kintex Ultrascale+ FPGAs in factory automation equipment requiring –40°C to +125°C operation. IC Role / Device Role / Timing Role: Industrial-grade controller with guaranteed specs over full temperature range and robust overvoltage/overcurrent protection. Use Value: Maintains ±0.75% output accuracy across temperature and survives 40V input transients per Absolute Maximum Ratings. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-channel synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3838EUHF-1#PBF | Same silicon, rated for 0°C to 85°C junction temperature; lower thermal specification than LTC3838IUHF-1#PBF | Suitable for commercial temperature applications only; not qualified for extended industrial environments | Select when ambient temperature remains below 85°C and cost sensitivity outweighs extended temp qualification |
| MP2918GL-Z | Single-chip dual-phase controller with integrated MOSFET drivers; lacks differential remote sensing and DTR functionality | Targeted at space-constrained consumer electronics; no support for >±200mV ground deviations or aggressive load-release suppression | Choose for compact, low-cost solutions where remote sensing accuracy and transient overshoot control are secondary |
Compared with LTC3838EUHF-1#PBF, the LTC3838IUHF-1#PBF guarantees full –40°C to +125°C operation and tighter current limit accuracy; versus MP2918GL-Z, it provides superior differential sensing, DTR-based overshoot reduction, and flexible multiphase timing control at the cost of discrete MOSFET drive.
Availability
LTC3838IUHF-1#PBF is available at Aetrix Electronics and suitable for ASIC core power supplies, high-density server VRMs, and industrial FPGA power systems requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LTC3838IUHF-1#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 its precision analog and power management portfolio. The company specializes in high-performance signal conditioning and power conversion ICs for demanding applications.
The LTC3838IUHF-1#PBF belongs to Linear's PolyPhase® synchronous buck controller family, designed specifically for high-efficiency, high-current, multi-rail power delivery in computing, communications, and industrial systems where tight regulation and fast transient response are critical.
FAQ
What is the operating temperature range guaranteed for the LTC3838IUHF-1#PBF?
The LTC3838IUHF-1#PBF is guaranteed to meet all specifications over a junction temperature range of –40°C to +125°C. This industrial-grade rating is confirmed in the Absolute Maximum Ratings table and Electrical Characteristics notes, distinguishing it from the commercial-grade LTC3838EUHF-1#PBF variant. Thermal design must ensure θJA = 34°C/W is maintained via proper PCB copper area and exposed pad soldering.
How does the DTR feature in the LTC3838IUHF-1#PBF reduce output voltage overshoot?
The DTR feature in the LTC3838IUHF-1#PBF monitors load-release transients by sensing voltage drop on the DTR1/DTR2 pins. When the pin voltage falls below half of INTVCC, the controller disables the bottom gate driver (BG1/BG2), allowing inductor current to decay faster and minimizing VOUT overshoot. This behavior is validated in Figures G07 and G08, showing up to 50% reduction in peak overshoot during 15A→0A transitions.
Can the LTC3838IUHF-1#PBF be configured for single-output, dual-phase operation?
Yes, the LTC3838IUHF-1#PBF supports single-output, dual-phase operation by shorting the VOUTSENSE1+ pin (Pin 12) to INTVCC. This action disables Channel 1's error amplifier and internally connects ITH1 to ITH2, causing both channels to share the same compensation network and regulation loop from Channel 2. The PHASMD pin then configures relative phase offset (0°/180°/240°) between the two phases.
What are the current sense configuration options supported by the LTC3838IUHF-1#PBF?
The LTC3838IUHF-1#PBF supports both RSENSE and inductor DCR current sensing. For RSENSE, Kelvin (4-wire) connections to SENSE1+/SENSE1– and SENSE2+/SENSE2– are required. For DCR sensing, SENSE+ pins connect to the DCR sense capacitor/resistor node, while SENSE– pins tie to the inductor VOUT node. The VRNG pin selects 30mV or 60mV maximum sense voltage thresholds for improved accuracy.
Does the LTC3838IUHF-1#PBF require external components for soft-start and tracking functions?
The LTC3838IUHF-1#PBF integrates a 1µA temperature-independent pull-up current source on each TRACK/SS1 and TRACK/SS2 pin. A capacitor from TRACK/SSx to ground sets the soft-start ramp time, while connecting an external voltage source enables output voltage tracking. No additional current sources or op-amps are needed - the internal circuitry directly regulates (VOUTSENSE1+ – VOUTSENSE1–) and (2•VDFB2+ – VDFB2–) to the smaller of 0.6V or the TRACK/SSx voltage.
LTC3838IUHF-1#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- PolyPhase®
- Package/Case:
- 38-WFQFN Exposed Pad
- 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):
- 4.5V ~ 38V
- Frequency - Switching:
- 200kHz ~ 2MHz
- Duty Cycle (Max):
- -
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Enable, Frequency Control, Phase Control, Power Good, Soft Start, Tracking
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 38-QFN (5x7)
LTC3838IUHF-1#PBF FAQ
1.How can I place an order for LTC3838IUHF-1#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3838IUHF-1#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 LTC3838IUHF-1#PBF reliable?
The price and inventory of LTC3838IUHF-1#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3838IUHF-1#PBF is usually 5 days.
3.What payment methods are accepted for LTC3838IUHF-1#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3838IUHF-1#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3838IUHF-1#PBF?
LTC3838IUHF-1#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3838IUHF-1#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 LTC3838IUHF-1#PBF?
For technical support, including LTC3838IUHF-1#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3838IUHF-1#PBF requirements.
6.How does Aetrix verify that LTC3838IUHF-1#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3838IUHF-1#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 LTC3838IUHF-1#PBF meets industry standards.
7.What is the process for return or replacement of LTC3838IUHF-1#PBF?
All LTC3838IUHF-1#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3838IUHF-1#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 LTC3838IUHF-1#PBF part is unused and in its original packaging.
Return procedure for LTC3838IUHF-1#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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