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Analog Devices Inc. LTC3838EUHF-1#PBF
- Part No.:
- LTC3838EUHF-1#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 38-WFQFN Exposed Pad
- Datasheet:
-
LTC3838EUHF-1#PBF.pdf
- Description:
- IC REG CTRLR BUCK 38QFN
- Quantity:
- Payment:
- Shipping:
Inventory:119
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Product details
Overview
LTC3838EUHF-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 such as ASIC power supplies.
For engineers reviewing the LTC3838EUHF-1#PBF datasheet, LTC3838EUHF-1#PBF pinout, LTC3838EUHF-1#PBF application, or LTC3838EUHF-1#PBF equivalent, key selection criteria include differential remote sensing capability (±500mV ground deviation tolerance on VOUT1), detect transient release (DTR) for overshoot suppression, programmable 200kHz–2MHz switching frequency, and thermally enhanced 38-pin QFN package with exposed PGND pad.
Technical Context
The LTC3838EUHF-1#PBF implements a controlled on-time, valley current mode architecture enabling fast transient response without clock delay and constant-frequency operation at steady load. Its proprietary DTR circuit monitors load-release events to dynamically reduce bottom gate off-time and suppress output voltage overshoot-especially critical at low output voltages like 0.6V.
Dual independent channels support either two regulated outputs or multiphase single-output configuration via phase synchronization (0°/180°/240° options). Channel 1 uses differential sensing at VOUTSENSE1±; Channel 2 employs a 2×VDFB2+–VDFB2– scheme. Current sensing supports both RSENSE and inductor DCR methods with VRNG-selectable 30mV/60mV thresholds.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 38V - supports wide-input industrial, telecom, and distributed power systems |
| Output Voltage Accuracy | ±0.67% (Ch1), ±0.75% (Ch2) over temperature - enables tight regulation for CPU/GPU core rails |
| Min On/Off Time | tON(MIN) = 30ns, tOFF(MIN) = 90ns - allows near 0% and near 100% duty cycles for extreme step-down (e.g., 12V→0.6V) |
| Switching Frequency | 200kHz to 2MHz (programmable via RT resistor) - balances efficiency, size, and EMI in space-constrained designs |
| Differential Sensing Range | ±500mV (Ch1), ±200mV (Ch2) ground deviation tolerance - maintains regulation despite PCB plane IR drops |
| Thermal Package | 38-pin (5mm × 7mm) QFN with exposed PGND pad - θJA = 34°C/W enables 15A/channel operation without forced air |
| Current Sense Options | RSENSE or inductor DCR sensing - eliminates sense resistor losses in high-current applications |
Pinout & Package
Package: 38-lead (5mm × 7mm) plastic QFN with exposed thermal pad (Pin 39 = PGND). Requires soldering of exposed pad to PCB for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VOUTSENSE1+ | Differential output sense (+) for Channel 1 | Connects to positive side of VOUT1 feedback divider; enables precise remote sensing up to ±500mV ground offset |
| VOUTSENSE1– | Differential output sense (–) for Channel 1 | Connects to negative terminal of VOUT1 capacitor; forms Kelvin-sense path to reject PCB trace resistance error |
| VDFB2+, VDFB2– | Differential feedback inputs for Channel 2 | Regulates 2×VDFB2+ – VDFB2– to 0.6V; supports 3-resistor divider for accurate differential sensing |
| SENSE1+, SENSE1– SENSE2+, SENSE2– | Valley current sense inputs (dual channel) | Accepts RSENSE or DCR signals; VRNG pin selects 30mV/60mV full-scale threshold |
| DTR1, DTR2 | Load-release transient detection | Pulled to INTVCC by 2.5µA source; falling below 0.5×INTVCC triggers BG turn-off to minimize overshoot |
| TG1, TG2 / BG1, BG2 | Top/bottom gate drivers | Drive external N-MOSFETs; 2.5Ω pull-up / 0.8–1.2Ω pull-down resistances ensure fast switching with low shoot-through risk |
| TRACK/SS1, TRACK/SS2 | Soft-start and voltage tracking inputs | Internal 1µA pull-up enables programmable ramp time; external voltage source enables output tracking during startup |
Key Features
| Feature | Design Value |
|---|---|
| Detect Transient Release (DTR) | Reduces VOUT overshoot during rapid load release by dynamically disabling bottom FET conduction |
| Dual differential output sensing | Enables ±500mV ground deviation tolerance on Channel 1 and ±200mV on Channel 2 for high-current PCB layouts |
| Controlled on-time valley current mode | Delivers fast transient response without clock latency while maintaining constant frequency under steady load |
| Programmable phase relationship | PHASMD pin selects 0°/180°/240° channel phase offset and CLKOUT timing for optimized multiphase current sharing |
| Flexible current sensing | Supports both precision RSENSE and lossless inductor DCR sensing with selectable 30mV/60mV thresholds via VRNG |
Applications
| ASIC Power Supply | Multi-Core Processor Rail |
|---|---|
Use Scenario: Providing tightly regulated 0.8V–1.2V power to high-performance ASICs in networking switches with dynamic load steps up to 15A/µs. IC Role / Device Role / Timing Role: Dual-channel PolyPhase® controller delivering synchronized, interleaved switching to reduce input/output ripple and improve transient response. Use Value: ±0.67% regulation accuracy and 30ns minimum on-time enable stable core voltage delivery under aggressive DVFS transitions. | Use Scenario: Generating independent 1.0V and 1.8V rails for CPU and I/O domains in embedded computing platforms with shared thermal constraints. IC Role / Device Role / Timing Role: Dual-output controller operating in independent mode with separate soft-start, tracking, and PGOOD monitoring per rail. Use Value: Differential sensing tolerates >300mV ground bounce between domains, ensuring regulation integrity across split-plane PCBs. |
| High-Density Telecom PSU | Industrial FPGA Power System |
Use Scenario: 48V-to-3.3V/1.2V conversion in compact base station power modules where board area and thermal density are critical. IC Role / Device Role / Timing Role: Multiphase single-output configuration using both channels in 180° interleaved mode to halve input capacitor RMS current. Use Value: 2MHz maximum switching frequency enables <10mm² total solution size while maintaining >92% efficiency at 12A. | Use Scenario: Powering Xilinx Kintex Ultrascale+ FPGAs requiring 0.85V core, 1.8V auxiliary, and sequencing compliance per Xilinx UG578. IC Role / Device Role / Timing Role: Dual-channel controller with TRACK/SS pins configured for precise power-up sequencing and voltage tracking. Use Value: Internal 1µA soft-start pull-up current enables repeatable, jitter-free ramp times without external components. |
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 |
|---|---|---|---|
| LTC3855IUFD#PBF | Single-channel, 4-phase capable; no DTR feature; ±0.5% regulation; 600kHz–4MHz range | Requires two ICs for dual independent outputs; better suited for ultra-high-current single-rail systems | Select when needing >30A single output with minimal phase count; avoid when DTR or dual independent regulation is required |
| MP8765GL-Z | Monolithic dual buck (integrated MOSFETs); 0.6V–5.5V output; ±1.5% accuracy; no differential sensing | Lower BOM count but limited to ≤12A/channel; lacks remote sensing and DTR for precision low-VOUT apps | Select for cost-sensitive, medium-current applications where layout simplicity outweighs regulation accuracy and transient performance |
Compared with LTC3855IUFD#PBF and MP8765GL-Z, the LTC3838EUHF-1#PBF uniquely combines dual independent differential regulation, DTR-based overshoot suppression, and 30ns minimum on-time-making it optimal for high-accuracy, high-transient ASIC/FPGA core supplies where external MOSFETs are preferred.
Availability
LTC3838EUHF-1#PBF is available at Aetrix Electronics and suitable for ASIC power supplies, multi-core processor rails, and high-density telecom PSUs requiring stable component supply, long-term lifecycle support, and guaranteed parametric compliance across –40°C to 125°C.
Supply support for LTC3838EUHF-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 high-performance analog and power management portfolio with rigorous automotive- and industrial-grade qualification.
The LTC3838EUHF-1#PBF belongs to Linear's PolyPhase® controller family, designed specifically for high-efficiency, high-transient-response DC/DC conversion in computing, data center, and communications infrastructure where precision regulation and multiphase scalability are essential.
FAQ
What is the operating temperature range for the LTC3838EUHF-1#PBF?
The LTC3838EUHF-1#PBF is rated for operation from –40°C to +125°C junction temperature. The "E" grade suffix indicates qualification across this full industrial temperature range, with specifications assured by design, characterization, and statistical process controls-not just tested at 25°C. This makes the LTC3838EUHF-1#PBF suitable for demanding environments such as base station power supplies and industrial motor drives where ambient temperatures exceed 85°C.
How does the DTR feature in the LTC3838EUHF-1#PBF reduce output voltage overshoot?
The DTR (Detect Transient Release) feature in the LTC3838EUHF-1#PBF monitors rapid load-current reduction by sensing voltage drop on the DTR1/DTR2 pins. When the pin voltage falls below half of INTVCC, the controller disables bottom gate (BG) drive earlier than normal, allowing inductor current to decay faster and minimizing VOUT overshoot-particularly effective at low output voltages like 0.6V. This behavior is confirmed in Figure G07/G08 of the LTC3838-1 datasheet, showing >50% overshoot reduction versus DTR-disabled operation.
Can the LTC3838EUHF-1#PBF be used in single-output, two-phase mode?
Yes, the LTC3838EUHF-1#PBF supports single-output, two-phase operation. By shorting VOUTSENSE1+ to INTVCC, Channel 1's error amplifier is disabled and ITH1 is internally tied to ITH2, causing both channels to share the same compensation network and regulation loop. PHASMD pin then sets the 180° or 240° phase offset between TG1 and TG2, enabling interleaved operation that cuts input/output ripple by up to 50% compared to single-phase designs.
What is the purpose of the VRNG pin on the LTC3838EUHF-1#PBF?
The VRNG pin on the LTC3838EUHF-1#PBF selects the full-scale current sense threshold: tying VRNG to SGND sets VSENSE(MAX) = 30mV; tying it to INTVCC sets VSENSE(MAX) = 60mV. This allows optimization of current-sense resolution and noise immunity-30mV for high-accuracy, low-current applications; 60mV for higher-current, lower-loss DCR sensing. The selection directly affects current limit accuracy, as documented in Table 1 comparing LTC3838-1 against other variants.
Does the LTC3838EUHF-1#PBF support external clock synchronization?
Yes, the LTC3838EUHF-1#PBF supports external clock synchronization via the MODE/PLLIN pin (Pin 5). Applying an external clock within ±30% of the RT-programmed frequency locks both channels to that clock while maintaining phase relationships defined by PHASMD. CLKOUT (Pin 6) can then serve as a synchronized output for cascading additional controllers-enabling deterministic timing across multi-rail power systems without jitter accumulation.
LTC3838EUHF-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)
LTC3838EUHF-1#PBF FAQ
1.How can I place an order for LTC3838EUHF-1#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3838EUHF-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 LTC3838EUHF-1#PBF reliable?
The price and inventory of LTC3838EUHF-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 LTC3838EUHF-1#PBF is usually 5 days.
3.What payment methods are accepted for LTC3838EUHF-1#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3838EUHF-1#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3838EUHF-1#PBF?
LTC3838EUHF-1#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3838EUHF-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 LTC3838EUHF-1#PBF?
For technical support, including LTC3838EUHF-1#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3838EUHF-1#PBF requirements.
6.How does Aetrix verify that LTC3838EUHF-1#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3838EUHF-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 LTC3838EUHF-1#PBF meets industry standards.
7.What is the process for return or replacement of LTC3838EUHF-1#PBF?
All LTC3838EUHF-1#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3838EUHF-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 LTC3838EUHF-1#PBF part is unused and in its original packaging.
Return procedure for LTC3838EUHF-1#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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