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Analog Devices Inc. LTC7821IUH#TRPBF
- Part No.:
- LTC7821IUH#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 32-WFQFN Exposed Pad
- Datasheet:
-
LTC7821IUH#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK HYBRID 32QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,700
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Product details
Overview
LTC7821IUH#TRPBF from Analog Devices is a hybrid synchronous step-down controller IC that integrates soft-switching charge pump topology with buck regulation for high-efficiency intermediate bus conversion. It operates from 10V to 72V input, delivers ±1% output voltage accuracy at 12V, supports 200kHz–1.5MHz programmable switching frequency, and enables >97% efficiency in 48V-to-12V/20A applications. It is used in telecom power systems requiring low EMI and fast transient response.
For engineers reviewing the LTC7821IUH#TRPBF datasheet, LTC7821IUH#TRPBF pinout, LTC7821IUH#TRPBF application, or LTC7821IUH#TRPBF equivalent, key selection criteria include its hybrid topology's soft-switching advantage over conventional controllers, RSENSE/DCR current sensing flexibility, monotonic start-up, and accurate current sharing for multiphase parallel operation.
Technical Context
The LTC7821IUH#TRPBF implements a proprietary hybrid architecture combining a charge-pump pre-regulator stage with a synchronous buck stage-enabling zero-voltage switching (ZVS) on high-side switches to reduce switching losses and EMI. Its phase-lockable oscillator supports synchronization across multiple phases via CLKOUT and MODE/PLLIN pins.
It features dual-stage gate drivers (TG1/TG2/BG1/BG2) with <4ns transition times and precise timing controls (e.g., T1D = 45ns, ton(MIN) = 210ns) optimized for discrete N-channel MOSFETs in a four-switch flying-capacitor configuration. The controller monitors MID_SENSE against VIN/2 using a programmable window comparator set by HYS_PRGM to ensure capacitor balancing integrity.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 10V to 72V (80V absolute max); supports wide-input industrial and telecom bus voltages without external pre-regulation. |
| Switching Frequency | 200kHz to 1.5MHz (programmable via FREQ pin); enables compact magnetics and faster load transient response vs. traditional 150–300kHz controllers. |
| Output Voltage Accuracy | ±1% over temperature and line/load; ensures stable 12V rail regulation in distributed power systems with tight tolerance requirements. |
| Current Sensing | RSENSE or DCR-based; allows flexible, low-loss inductor current monitoring without added shunt power loss. |
| Operating Temp Range | –40°C to +125°C junction; qualified for automotive under-hood and industrial embedded environments. |
| Package | 32-pin 5mm × 5mm QFN with exposed thermal pad; provides low θJC = 7.3°C/W for high-power density layouts. |
| Soft-Start | Monotonic VOUT ramp via TRACK/SS pin; prevents inrush current and output overshoot during cold-start in multi-rail systems. |
Pinout & Package
Package: 32-lead (5mm × 5mm) plastic QFN with exposed pad (Pin 33 = SGND), rated for –40°C to +125°C operating junction temperature.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (28) | Main input supply connection | Accepts 10–72V DC input; requires local ceramic bypass to PGND for stability and noise suppression. |
| SW1 (29), SW3 (20) | High-side and mid-point switch nodes | Drive flying capacitor (CFLY) and mid-rail capacitor (CMID); swing between VIN/2 and VIN (SW1) or GND and VIN/2 (SW3). |
| MID_SENSE (26) | Kelvin sense input for half-rail voltage | Monitors CMID voltage deviation from VIN/2; triggers FAULT and capacitor rebalancing if outside HYS_PRGM-set window. |
| ITH (10) | Error amplifier output / current limit threshold | Sets peak inductor current via voltage-controlled comparator; enables precise current-mode control and loop compensation. |
| CLKOUT (2) | Phase-inverted clock output | Provides 180° out-of-phase signal for synchronizing parallel LTC7821IUH#TRPBF controllers in multiphase configurations. |
| PGOOD (5) | Open-drain power-good indicator | Asserts low after 50μs mask timer if VFB deviates >±7.5% from target; signals system controller of valid output regulation. |
| SGND (33) | Signal ground (exposed pad) | Mandatory PCB solder connection; serves as reference for all analog circuitry and must be tied to PGND at single point. |
Key Features
| Feature | Design Value |
|---|---|
| Hybrid soft-switching topology | Reduces switching losses and EMI vs. hard-switched buck controllers-enables >97% efficiency at 500kHz in 48V→12V conversion. |
| Programmable operating mode | Select CCM, DCM, or Burst Mode® via MODE/PLLIN pin; optimizes light-load efficiency without compromising transient performance. |
| Accurate current sharing | Enables parallel operation of multiple LTC7821IUH#TRPBF units with matched output current distribution (<±5% mismatch). |
| Capacitor balancing control | Automatic CFLY/CMID charging to VIN/2 during startup and fault recovery-ensures safe, balanced operation of flying-capacitor stage. |
| EXTVCC input support | Allows external 7–40V supply to power INTVCC LDO, improving efficiency by bypassing internal VIN-derived regulator. |
Applications
| Telecom Intermediate Bus Converter | High-Density Datacom Power Supply |
|---|---|
|
Use Scenario: 48V backplane powering 12V ASIC rails in 1RU server blades. IC Role / Device Role / Timing Role: Primary hybrid step-down controller managing four discrete MOSFETs and flying/mid capacitors to generate regulated 12V/20A output. Use Value: Achieves >97% efficiency at 500kHz, reducing thermal load and enabling higher power density than conventional 200kHz controllers. |
Use Scenario: Distributed 12V power delivery across multi-board FPGA acceleration modules. IC Role / Device Role / Timing Role: Synchronized multiphase controller using CLKOUT and MODE/PLLIN to coordinate parallel LTC7821IUH#TRPBF units. Use Value: Enables precise current sharing and phase interleaving-reducing input/output ripple and improving dynamic response to bursty FPGA loads. |
| Automotive ADAS Domain Controller | Industrial Storage System PSU |
|
Use Scenario: 48V battery-powered vision processing unit requiring clean, isolated 12V rail. IC Role / Device Role / Timing Role: High-reliability step-down controller with monotonic start-up, UVLO hysteresis (0.28V), and overtemperature shutdown. Use Value: Meets AEC-Q100 stress requirements via –40°C to +125°C qualification and robust fault handling (FAULT/PGOOD signaling). |
Use Scenario: Redundant 12V power for NVMe SSD arrays in enterprise storage enclosures. IC Role / Device Role / Timing Role: Fault-tolerant controller with capacitor balancing, short-circuit protection, and EXTVCC-assisted efficiency boost. Use Value: Maintains stable output during hot-swap events and input transients-verified by 10V/ms line transient test data in datasheet Figure G23. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar hybrid/hard-switched step-down controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC7820IUH#TRPBF | Lower VIN range (4.5–60V), no CLKOUT, fixed 500kHz frequency, no EXTVCC input. | Suitable for cost-sensitive 12V/24V input systems where multiphase sync and ultra-wide input are unnecessary. | Choose LTC7820IUH#TRPBF when design prioritizes simplicity and lower BOM count over programmability and efficiency headroom. |
| MP2918GL-Z | Hard-switched 4-switch buck-boost controller; no flying-capacitor soft-switching; max 60V VIN; no capacitor balancing logic. | Used in bidirectional or wide-VIN non-isolated converters where ZVS is not required and topology flexibility outweighs EMI constraints. | Choose MP2918GL-Z only if topology must support both buck and boost modes-and soft-switching EMI reduction is secondary. |
Compared with LTC7820IUH#TRPBF and MP2918GL-Z, the LTC7821IUH#TRPBF uniquely delivers soft-switching benefits at high frequency, full capacitor balancing autonomy, and synchronized multiphase capability-making it optimal for high-efficiency, low-EMI intermediate bus designs where VIN ≥ 40V.
Availability
LTC7821IUH#TRPBF is available at Aetrix Electronics and suitable for telecom power supplies, datacom server boards, and automotive ADAS domain controllers requiring stable component supply, long lifecycle support, and guaranteed industrial temperature grade.
Supply support for LTC7821IUH#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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LTC7821IUH#TRPBF belongs to Analog Devices' Power by Linear™ controller family, designed specifically for high-efficiency, high-density intermediate bus conversion using hybrid soft-switching topologies in telecom and datacenter infrastructure.
FAQ
What is the primary topology implemented by the LTC7821IUH#TRPBF?
The LTC7821IUH#TRPBF implements a proprietary hybrid topology combining a soft-switching charge pump stage with a synchronous step-down converter. This architecture achieves zero-voltage switching on high-side MOSFETs, significantly reducing switching losses and EMI compared to conventional hard-switched buck controllers-enabling >97% efficiency at 500kHz in 48V-to-12V conversion.
How does the LTC7821IUH#TRPBF handle capacitor balancing during startup?
The LTC7821IUH#TRPBF automatically balances CFLY and CMID capacitors to VIN/2 during power-up using internal current sources controlled by the TIMER pin. When TIMER voltage reaches 0.5V, charging begins; completion before 1.2V releases TRACK/SS and starts normal operation. If unbalanced at 1.2V, it enters auto-retry mode-halving TIMER slew rate until 4V, then resetting and repeating-ensuring safe hybrid operation before enabling MOSFETs.
Can the LTC7821IUH#TRPBF operate without an external flying capacitor?
No-the LTC7821IUH#TRPBF requires external flying (CFLY) and mid-rail (CMID) capacitors as core elements of its hybrid topology. These capacitors enable the charge-pump pre-regulation stage that delivers soft-switching benefits. Omitting them invalidates the controller's operating principle and will prevent proper regulation or cause immediate FAULT assertion due to MID_SENSE imbalance.
What is the function of the HYS_PRGM pin on the LTC7821IUH#TRPBF?
The HYS_PRGM pin on the LTC7821IUH#TRPBF sets the voltage window around VIN/2 used by the MID_SENSE comparator. A resistor from HYS_PRGM to ground generates a reference that defines equal upper/lower thresholds (e.g., ±0.8V when tied to INTVCC). If MID_SENSE deviates beyond this window during operation, the LTC7821IUH#TRPBF asserts FAULT, halts switching, and initiates capacitor rebalancing to restore safe operation.
Does the LTC7821IUH#TRPBF support synchronization with external clock sources?
Yes-the LTC7821IUH#TRPBF supports external synchronization via the MODE/PLLIN pin. Applying a clock signal to this pin engages the integrated PLL, which locks the internal oscillator to the external frequency within 200kHz–1500kHz range. In sync mode, forced continuous conduction mode (CCM) is enabled, ensuring deterministic phase alignment across multiple LTC7821IUH#TRPBF units in multiphase systems.
LTC7821IUH#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 32-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Number of Outputs:
- 1
- Output Phases:
- 2
- Voltage - Supply (Vcc/Vdd):
- 10V ~ 72V
- Frequency - Switching:
- 200kHz ~ 1.5MHz
- Duty Cycle (Max):
- 40%
- Synchronous Rectifier:
- No
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable, Frequency Control, Power Good, Soft Start, Tracking
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-QFN (5x5)
LTC7821IUH#TRPBF FAQ
1.How can I place an order for LTC7821IUH#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC7821IUH#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 LTC7821IUH#TRPBF reliable?
The price and inventory of LTC7821IUH#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC7821IUH#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC7821IUH#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC7821IUH#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC7821IUH#TRPBF?
LTC7821IUH#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC7821IUH#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 LTC7821IUH#TRPBF?
For technical support, including LTC7821IUH#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC7821IUH#TRPBF requirements.
6.How does Aetrix verify that LTC7821IUH#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC7821IUH#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 LTC7821IUH#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC7821IUH#TRPBF?
All LTC7821IUH#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC7821IUH#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 LTC7821IUH#TRPBF part is unused and in its original packaging.
Return procedure for LTC7821IUH#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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