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Analog Devices Inc. LTC3823IUH#PBF
- Part No.:
- LTC3823IUH#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 32-WFQFN Exposed Pad
- Datasheet:
-
LTC3823IUH#PBF.pdf
- Description:
- IC REG CTRLR BUCK 32QFN
- Quantity:
- Payment:
- Shipping:
Inventory:591
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Product details
Overview
LTC3823IUH#PBF from Analog Devices (formerly Linear Technology) is a synchronous step-down DC/DC controller with true remote differential output sensing, output voltage tracking, and PLL-based external clock synchronization. It operates from 4.5V to 36V input, delivers 0.6V to ≤3.3V output (with remote sense), supports <100ns minimum on-time, and features ±0.67% reference accuracy - enabling high-precision power delivery for server CPU cores, ASICs, and DDR memory rails.
For engineers reviewing the LTC3823IUH#PBF datasheet, LTC3823IUH#PBF pinout, LTC3823IUH#PBF application, or LTC3823IUH#PBF equivalent, key selection criteria include its valley current mode control without RSENSE, programmable cycle-by-cycle current limit via VRNG/ITH, differential remote sensing architecture, and compatibility with dual N-channel MOSFETs in high-efficiency 2.5V/10A server point-of-load designs.
Technical Context
The LTC3823IUH#PBF implements constant on-time, valley current mode control using an internal one-shot timer whose duration is set by ION current and VON voltage - enabling stable operation at ultra-low duty cycles without a sense resistor. Its differential remote sensing amplifier (ADA = 0.9965–1.0035 V/V, VOS = 2mV) rejects PCB trace IR drop to maintain ±0.67% output regulation accuracy under load.
Phase-locked loop synchronization (PLLIN input, PLLFLTR filter pin) allows precise frequency alignment to external clocks up to 1MHz, while the adjustable current limit (via VRNG pin) sets nominal sense thresholds from 50mV to 200mV - supporting both discrete sense resistors and MOSFET RDS(ON)-based current sensing with foldback protection active below 0.75V ITH.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 4.5V to 36V - supports wide-input industrial and telecom power rails without pre-regulation. |
| Reference Voltage | 0.6V ±0.67% - enables accurate low-voltage regulation for modern processors and memory. |
| Min On-Time | <100ns - permits high VIN-to-low VOUT conversion (e.g., 24V→1.2V @ 200kHz) without pulse-skipping. |
| Duty Cycle Range | 2% to 90% @ 200kHz - ensures stable operation across full input/output combinations. |
| Remote Sensing Gain | 0.9965–1.0035 V/V - maintains ≤3.5mV error over temperature for ±1% output accuracy at load. |
| PGOOD Threshold | ±11% of VFB - provides reliable power-good signaling with 20μs fault mask timing. |
| Shutdown Current | 30μA - enables low-power system standby modes without auxiliary regulators. |
Pinout & Package
Package: 32-lead (5mm × 5mm) plastic QFN with exposed SGND pad (Pin 33), rated θJA = 34°C/W. Thermal pad must be soldered to PCB ground for electrical integrity and thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VRNG (Pin 1) | Sense voltage range select | Sets nominal current sense threshold (50–200mV) via resistive divider; determines max valley current limit. |
| VFB (Pin 2) | Error amplifier feedback input | Connects to output voltage divider; regulates output to 0.6V reference with ±0.67% accuracy. |
| ITH (Pin 3) | Error amp output / current threshold | 0.75V = zero-current threshold; 0–2.4V range controls valley current limit per cycle. |
| SGND (Pin 4) | Signal ground reference | Reference for all small-signal pins; must connect to PGND at single point to avoid noise coupling. |
| ION (Pin 5) | On-time current source | Current sink (–1.3 to –2.3μA) sets switching frequency via external RON resistor. |
| VDIFFOUT (Pin 6) | Differential sense amplifier output | Drives VFB directly or through divider; enables Kelvin sensing of remote load point. |
| VOUTSENSE+ (Pin 8) | Remote sense positive input | Connects to + terminal of output capacitor; rejects trace resistance between IC and load. |
| VOUTSENSE– (Pin 9) | Remote sense negative input | Connects to – terminal of output capacitor; completes differential measurement path. |
| TRACK/SS (Pin 11) | Tracking/soft-start control | Internal 1.7μA current charges external capacitor for controlled ramp-up or master-slave sequencing. |
| PLLFLTR (Pin 12) | PLL low-pass filter node | External RC network sets PLL bandwidth; defaults to 1.180V when unsynchronized. |
| PLLIN (Pin 13) | External clock input | 50kΩ internal termination accepts 100kHz–1MHz square wave for frequency lock. |
| VIN (Pin 14) | Main supply input | Primary power for control circuitry; decoupled to PGND with 0.1–1μF ceramic capacitor. |
| VINSNS (Pin 15) | VIN sense input | Optional separate sense for bootstrap supply monitoring; tied to VIN in standard configurations. |
| INTVCC (Pin 19) | Internal 5V regulator output | Powers logic and gate drivers; requires ≥4.7μF low-ESR capacitor to PGND. |
| DRVCC (Pin 20) | Driver supply input | Must be externally connected to INTVCC; co-bonded in SSOP but separate in QFN for layout flexibility. |
| BG (Pin 21) | Bottom gate driver output | Drives N-MOSFET source to PGND; 0.7–1.5Ω pull-down resistance supports fast turn-off. |
| PGND (Pin 22) | Power ground return | High-current return for bottom FET, CIN, and CVCC; must be low-inductance connection to MOSFET source. |
| SENSE– (Pin 23) | Current sense negative input | Kelvin connection to bottom FET source or sense resistor; rejects common-mode noise. |
| SENSE+ (Pin 24) | Current sense positive input | Connected to SW node (no RSENSE) or top of sense resistor; enables MOSFET RDS(ON) sensing. |
| SW (Pin 25) | Switch node | Connects to inductor and bootstrap capacitor; swings from ~–0.4V to VIN during operation. |
| TG (Pin 26) | Top gate driver output | Drives N-MOSFET gate with INTVCC-referenced swing; 1.9–2.5Ω pull-up supports fast turn-on. |
| BOOST (Pin 27) | Bootstrap supply | Floats with SW node; supplies TG driver; requires Schottky diode and 0.1μF ceramic capacitor. |
| FCB (Pin 29) | Forced continuous mode | Ground = forced CCM at light load; INTVCC = DCM enabled; enables efficiency vs. ripple tradeoff. |
| RUN (Pin 30) | Enable/disable control | 1.5V threshold; <1.5V disables both FETs and reduces supply current to 30μA. |
| VON (Pin 31) | On-time voltage input | Clamped 0.6V–4.8V; ties tON to VOUT for constant-frequency operation across output changes. |
| PGOOD (Pin 32) | Open-drain power-good flag | Pulled low if VFB deviates >±11%; includes 20μs blanking after startup to avoid false trips. |
| SGND (Pin 33) | Exposed thermal pad | Must be soldered to PCB ground plane; provides primary thermal path and signal reference. |
Key Features
| Feature | Design Value |
|---|---|
| No RSENSE operation | Uses bottom MOSFET RDS(ON) for current sensing - eliminates sense resistor losses and BOM cost. |
| Differential remote sensing | True Kelvin sensing with 0.9965–1.0035 gain and 2mV offset - maintains ±1% output accuracy at load point. |
| Programmable current limit | VRNG pin selects 50–200mV nominal sense threshold - enables precise, temperature-compensated overcurrent protection. |
| PLL synchronization | Accepts external clock up to 1MHz via PLLIN - eliminates beat frequencies in multi-rail systems. |
| Adjustable soft-start | 1.7μA internal current charges external capacitor at TRACK/SS - enables controlled power-up and sequencing. |
| Micropower shutdown | 30μA quiescent current in shutdown - supports low-power standby without auxiliary LDOs. |
Applications
| Server CPU Core Power | ASIC Point-of-Load Supply |
|---|---|
Use Scenario: Delivering tightly regulated 1.2V/15A to high-performance x86 CPU cores with dynamic load steps up to 10A/μs. IC Role / Device Role / Timing Role: Synchronous step-down controller managing dual N-MOSFETs, remote sensing at CPU socket, and PLL sync to system clock. Use Value: <0.67% reference accuracy and differential sensing ensure ±12mV output tolerance under worst-case PCB IR drop and thermal drift. | Use Scenario: Generating 0.85V/8A for FPGA or AI accelerator with strict transient response and sequencing requirements. IC Role / Device Role / Timing Role: Primary controller with TRACK/SS pin configured as slave to coordinate startup with main rail. Use Value: Output voltage tracking ensures ASIC rail ramps within 100ms of core voltage, preventing latch-up during power-up. |
| DDR Memory VDDQ Supply | Industrial Programmable Logic Controller |
Use Scenario: Providing 1.35V/6A to DDR4 memory modules with low noise and high PSRR for signal integrity. IC Role / Device Role / Timing Role: Constant-frequency controller synchronized to system bus clock via PLLIN to minimize EMI. Use Value: 200kHz fixed frequency (set via ION resistor) and <100ns min on-time enable clean 1.35V regulation from 12V input without sub-harmonic instability. | Use Scenario: Converting 24V factory bus to isolated 3.3V/2A for PLC I/O modules operating in –40°C to 85°C ambient. IC Role / Device Role / Timing Role: Wide-input controller with undervoltage lockout (VIN UVLO = 3.4V) and thermal shutdown (170°C). Use Value: 4.5V–36V input range and –40°C to 85°C guaranteed operation eliminate need for input pre-regulators in harsh environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3855IUFD#PBF | Higher integration: integrated 5V LDO for gate drive, no external BOOST diode required; supports 0.6V–5V output. | Eliminates external Schottky diode and reduces component count; better suited for space-constrained designs. | Select LTC3855IUFD#PBF when board area is critical and 5V gate drive simplification outweighs higher cost. |
| MP2918GL-Z | Fixed 600kHz frequency; no PLL sync; uses internal current sense amplifier instead of direct MOSFET RDS(ON) sensing. | Lacks remote sensing and tracking; optimized for cost-sensitive consumer applications rather than precision server rails. | Select MP2918GL-Z only for non-critical 12V→3.3V/5A applications where ±2% regulation and no sequencing are acceptable. |
Compared with LTC3855IUFD#PBF, the LTC3823IUH#PBF offers superior remote sensing accuracy and flexible frequency programming but requires external bootstrap diode; versus MP2918GL-Z, it delivers tighter regulation, tracking, and industrial temperature support at higher BOM cost.
Availability
LTC3823IUH#PBF is available at Aetrix Electronics and suitable for server power supplies, ASIC point-of-load converters, and DDR memory VDDQ regulation requiring stable component supply across extended product lifecycles.
Supply support for LTC3823IUH#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 technical and manufacturing continuity for all Linear power products.
The LTC3823IUH#PBF belongs to Linear's high-performance synchronous controller family, designed specifically for precision, high-current DC/DC conversion in datacenter, networking, and industrial computing applications.
FAQ
What is the minimum on-time specification for the LTC3823IUH#PBF and why does it matter?
The LTC3823IUH#PBF has a minimum on-time of <100ns, verified across temperature and process corners. This spec enables high step-down ratios - such as converting 24V input to 1.2V output at 200kHz - without pulse-skipping or sub-harmonic oscillation. In the LTC3823IUH#PBF, this is achieved via a precision one-shot timer architecture that avoids reliance on sense resistors, preserving efficiency in high-VIN, low-VOUT applications.
How does the LTC3823IUH#PBF implement remote differential sensing and what accuracy does it achieve?
The LTC3823IUH#PBF integrates a dedicated differential amplifier with 0.9965–1.0035 V/V gain, 2mV input offset, and 90dB PSRR. VOUTSENSE+ and VOUTSENSE– connect directly to the load capacitor terminals, rejecting PCB trace resistance. When used with the internal 0.6V reference and ±0.67% VFB accuracy, the LTC3823IUH#PBF maintains ≤±1% output regulation at the load point under full thermal and line/load conditions.
Can the LTC3823IUH#PBF operate without an external current sense resistor?
Yes - the LTC3823IUH#PBF supports true No RSENSE operation by using the bottom N-MOSFET's RDS(ON) as the current sense element. Connect SENSE+ to the SW node and SENSE– to PGND. The VRNG pin configures the nominal sense threshold (50–200mV), and the ITH voltage adjusts the valley current limit dynamically. This eliminates sense resistor losses and improves efficiency, especially in high-current designs.
What is the role of the TRACK/SS pin on the LTC3823IUH#PBF and how is it used in multi-rail systems?
The TRACK/SS pin on the LTC3823IUH#PBF serves dual functions: soft-start ramp generation (via internal 1.7μA current charging an external capacitor) and output voltage tracking. In multi-rail systems, one LTC3823IUH#PBF acts as master (capacitor on TRACK/SS), while others act as slaves (resistive divider from master's VFB applied to TRACK/SS). This ensures coordinated startup and tight voltage sequencing - critical for FPGAs, CPUs, and memory interfaces.
Does the LTC3823IUH#PBF support external clock synchronization and what is its frequency range?
Yes - the LTC3823IUH#PBF includes a phase-locked loop with dedicated PLLIN and PLLFLTR pins. It accepts external square-wave clocks from 100kHz to 1MHz, locking its switching frequency precisely to the input. This eliminates beat frequencies in multi-controller systems and reduces EMI by aligning switching edges - a key requirement in dense server and telecom power architectures.
LTC3823IUH#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 32-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 4.5V ~ 36V
- Frequency - Switching:
- -
- Duty Cycle (Max):
- 90%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Enable, On Time Control, Power Good, Soft Start, Tracking
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-QFN (5x5)
LTC3823IUH#PBF FAQ
1.How can I place an order for LTC3823IUH#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3823IUH#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 LTC3823IUH#PBF reliable?
The price and inventory of LTC3823IUH#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3823IUH#PBF is usually 5 days.
3.What payment methods are accepted for LTC3823IUH#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3823IUH#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3823IUH#PBF?
LTC3823IUH#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3823IUH#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 LTC3823IUH#PBF?
For technical support, including LTC3823IUH#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3823IUH#PBF requirements.
6.How does Aetrix verify that LTC3823IUH#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3823IUH#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 LTC3823IUH#PBF meets industry standards.
7.What is the process for return or replacement of LTC3823IUH#PBF?
All LTC3823IUH#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3823IUH#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 LTC3823IUH#PBF part is unused and in its original packaging.
Return procedure for LTC3823IUH#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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