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Analog Devices Inc. LTC7820IUFD#PBF
- Part No.:
- LTC7820IUFD#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LTC7820IUFD#PBF.pdf
- Description:
- IC CHARGE PUMP DC/DC CTRLR 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,731
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Product details
Overview
LTC7820IUFD#PBF from Analog Devices is a fixed-ratio, high-voltage, high-power switched-capacitor (charge pump) DC/DC controller for non-isolated intermediate bus conversion. It drives four external N-channel MOSFETs to implement 2:1 voltage divider (VIN ≤ 72V → VOUT ≈ VIN/2), 1:2 voltage doubler (VIN ≤ 36V → VOUT ≈ 2×VIN), or 1:1 inverting topologies. Achieves >99% peak efficiency at 5A output and operates with programmable 100kHz–1MHz switching frequency. Used in high-density bus converters for telecom and industrial power systems.
For engineers reviewing the LTC7820IUFD#PBF datasheet, LTC7820IUFD#PBF pinout, LTC7820IUFD#PBF application, or LTC7820IUFD#PBF equivalent, key selection factors include its 28-pin 4mm × 5mm QFN package with HV-safe pin spacing, input current sensing with 50mV overcurrent threshold, soft-start pre-balancing capability, and dual INTVCC/EXTVCC biasing for efficiency optimization above 15V input.
Technical Context
The LTC7820IUFD#PBF implements open-loop, constant-frequency charge-pump control with precisely timed gate drive sequencing: G1/G3 operate in-phase at ~50% duty cycle, while G2/G4 operate complementarily to enable capacitor energy transfer across phases. It uses floating bootstrap drivers (BOOST1–BOOST3) to bias high-side MOSFET gates, with anti-shoot-through logic ensuring safe dead-time between complementary switches.
Protection is implemented via dedicated analog comparators: VLOW_SENSE is monitored against a programmable window centered at VHIGH_SENSE/2 (set by HYS_PRGM), ISENSE+–ISENSE− is compared to a 50mV threshold for overcurrent, and INTVCC UVLO (5.05V rising) disables operation below bias rail integrity. Fault conditions pull open-drain FAULT and PGOOD low with no automatic retry unless TIMER capacitor is configured for timed recovery.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology Support | Fixed-ratio voltage divider (2:1), doubler (1:2), or inverter (1:1); no closed-loop regulation - output depends on capacitor matching and load stability. |
| Max Input Voltage | 72V for 2:1 divider mode; 36V for 1:2 doubler or 1:1 inverter - defined by absolute max ratings and safe operating area of external MOSFETs. |
| Switching Frequency | 100kHz to 1MHz, linearly programmed via FREQ pin current (10µA sink); enables trade-off between efficiency (lower fSW) and component size (higher fSW). |
| Overcurrent Threshold | 50mV differential across RSENSE (ISENSE+ to ISENSE−); corresponds to precise current limit independent of temperature or supply variation. |
| Package | 28-lead 4mm × 5mm QFN (UFD) with exposed thermal pad (Pin 29 = GND); includes NC pins (2,10,13,26) for HV isolation between adjacent high-voltage nodes. |
| Efficiency | ≥99% peak at 5A load in 48V→24V divider configuration; achieved via zero-voltage switching (ZVS) behavior and low-loss gate drive architecture. |
| Bias Supply Options | Dual-path INTVCC regulation: internal LDO from VCC (6–72V), or more efficient EXTVCC LDO (12–40V) enabled when VCC > 7V and EXTVCC > 6.5V. |
Pinout & Package
Package: 28-lead (4mm × 5mm) plastic QFN (UFD) with exposed thermal pad (Pin 29 = GND). Pin spacing optimized for high-voltage compatibility; NC pins (2,10,13,26) electrically isolated and must remain floating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VHIGH_SENSE (1) | Kelvin sense input | Monitors drain voltage of top MOSFET (M1); sets reference for VLOW_SENSE window and pre-balance timing - critical for fault detection accuracy. |
| G1 (24), G2 (21), G3 (17), G4 (15) | Gate drivers | G1/G3 drive upper MOSFETs with floating BOOST1/BOOST3 rails; G2/G4 drive lower/synchronous MOSFETs referenced to GND or VLOW - enables full-N-channel implementation. |
| ISENSE+ (27), ISENSE− (28) | High-side current sense inputs | Measure differential voltage across external RSENSE at M1 drain; 50mV threshold triggers immediate FAULT assertion - supports pulse-current overload protection. |
| VLOW_SENSE (19), VLOW (20) | Half-voltage monitoring & node | VLOW_SENSE compares against VHIGH_SENSE/2 window; VLOW is the regulated half-voltage output node - forms core of charge-pump voltage division. |
| FREQ (5), HYS_PRGM (3), TIMER (4) | Programmable analog inputs | FREQ sets switching frequency via 10µA sink; HYS_PRGM configures VLOW_SENSE window hysteresis; TIMER sets pre-balance duration and short-circuit retry timeout. |
| FAULT (9), PGOOD (7), RUN (6), UV (8) | Control/status signals | Open-drain FAULT/PGOOD indicate faults or undervoltage; RUN enables/disables operation (1.22V threshold); UV provides system-level undervoltage supervision. |
| INTVCC (12), EXTVCC (11), VCC (14) | Bias supply inputs | VCC powers internal LDO; EXTVCC enables higher-efficiency auxiliary LDO when >6.5V; INTVCC is regulated 5.6V output powering all logic and drivers - requires ≥4.7µF ceramic bypass. |
Key Features
| Feature | Design Value |
|---|---|
| Soft-switching architecture | Enables >99% peak efficiency and ultra-low EMI by minimizing switching losses and eliminating reverse-recovery currents in external MOSFETs. |
| Pre-balance startup sequence | Internally sources 93mA from ISENSE+ to VLOW during power-up to safely equalize flying capacitors before switching - prevents inrush damage. |
| Programmable fault window | HYS_PRGM pin accepts resistor to set asymmetric upper/lower thresholds for VLOW_SENSE vs VHIGH_SENSE/2 - allows tuning for capacitor tolerance and load transient response. |
| High-voltage compatible layout | NC pins (2,10,13,26) and wide creepage spacing in 4mm × 5mm QFN package support reliable operation up to 72V input without PCB creepage compromises. |
| Dual bias supply path | Automatic switchover to EXTVCC LDO when VCC > 7V and EXTVCC > 6.5V reduces IC power dissipation and junction temperature - critical for high-power density designs. |
Applications
| Telecom Intermediate Bus Conversion | Industrial High-Density Power Supply |
|---|---|
Use Scenario: Converting 48V backplane to 24V intermediate bus in 1RU telecom servers with strict height constraints. IC Role / Device Role / Timing Role: LTC7820IUFD#PBF acts as fixed-ratio charge-pump controller driving discrete 100V MOSFETs; provides 2:1 step-down without magnetic components. Use Value: Enables 500W+ power delivery in <3mm profile using only ceramic capacitors - eliminates bulky inductors and reduces board area by >40% vs buck converters. |
Use Scenario: Generating 12V from 24V input in PLC I/O modules where EMI must meet CISPR-32 Class A limits. IC Role / Device Role / Timing Role: LTC7820IUFD#PBF implements soft-switched voltage divider with 200kHz fSW to minimize conducted emissions; gate timing ensures ZVS across load range. Use Value: Achieves >98.5% efficiency at full load with near-sinusoidal switch-node waveforms - eliminates need for ferrite beads or shielding cans. |
| Automotive ADAS Domain Controller Power | Test Equipment High-Voltage Auxiliary Rail |
Use Scenario: Deriving ±12V rails from 24V battery supply in radar ECU with -40°C to 125°C ambient requirement. IC Role / Device Role / Timing Role: LTC7820IUFD#PBF configured as inverter topology; leverages guaranteed operation over full industrial temp range and robust fault protection. Use Value: Delivers clean, low-noise bipolar outputs with <10mVpp ripple - avoids interference with sensitive RF front-end circuitry. |
Use Scenario: Providing 72V auxiliary supply from 48V lab bench source in automated test equipment requiring fast transient response. IC Role / Device Role / Timing Role: LTC7820IUFD#PBF used in 2:1 divider with external 100V MOSFETs; programmable TIMER sets 100ms retry delay after overcurrent shutdown. Use Value: Supports 10A pulsed loads with <50µs recovery from short-circuit - enables unattended burn-in testing without manual reset. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar fixed-ratio charge-pump controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC7821IUFD#PBF | Includes integrated MOSFET drivers with enhanced shoot-through protection and wider VCC range (4.5–80V); same pinout and feature set but improved robustness at extreme VIN. | Preferred for 72V+ input systems or environments with high dv/dt transients where gate drive reliability is critical. | Select LTC7821IUFD#PBF when operating near absolute maximum ratings or requiring tighter timing control under voltage stress. |
| MPQ7222GJ-A-Z | Monolithic 2:1 charge-pump converter (no external MOSFETs); 3A max output; fixed 1.2MHz fSW; smaller 2x2mm QFN package. | Suitable for space-constrained, lower-power applications (<100W); lacks programmability, fault window tuning, and high-voltage flexibility of LTC7820IUFD#PBF. | Choose MPQ7222GJ-A-Z only for cost-sensitive, low-power designs where integration outweighs configurability and voltage scalability. |
Compared with LTC7821IUFD#PBF, the LTC7820IUFD#PBF offers identical topology support and pin compatibility but trades enhanced gate drive robustness for slightly lower VCC minimum; versus MPQ7222GJ-A-Z, it delivers 5× higher power capability and full external component control at the expense of board-level integration.
Availability
LTC7820IUFD#PBF is available at Aetrix Electronics and suitable for telecom intermediate bus conversion, industrial high-density power supplies, and automotive ADAS domain controllers requiring stable component supply and long-term production continuity.
Supply support for LTC7820IUFD#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 (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, communications, and power management markets.
The LTC7820IUFD#PBF belongs to ADI's Power by Linear™ portfolio of high-efficiency, high-voltage DC/DC controllers designed specifically for non-isolated, high-power-density intermediate bus applications where magnetics-free solutions are required.
FAQ
What topology configurations does the LTC7820IUFD#PBF support?
The LTC7820IUFD#PBF supports three fixed-ratio topologies: 2:1 voltage divider (input up to 72V), 1:2 voltage doubler (input up to 36V), and 1:1 inverting (input up to 36V). It does not provide closed-loop regulation - output voltage is determined by capacitor ratios and load conditions. Each mode uses the same four-gate-drive architecture with reconfigured external MOSFET connections, and all modes leverage the same pre-balance, fault protection, and frequency programming features built into the LTC7820IUFD#PBF.
How does the LTC7820IUFD#PBF achieve >99% efficiency?
The LTC7820IUFD#PBF achieves >99% peak efficiency through zero-voltage switching (ZVS) behavior inherent to its charge-pump architecture, which eliminates MOSFET turn-on switching losses and diode reverse-recovery losses. Its precisely timed gate drive sequencing (G1/G3 in-phase, G2/G4 complementary) ensures minimal overlap and optimal capacitor energy transfer. Combined with low-RDS(on) external MOSFET selection and dual-path INTVCC regulation (including EXTVCC option), the LTC7820IUFD#PBF sustains >98.5% efficiency across 20–100% load in validated 48V→24V divider designs.
What is the purpose of the HYS_PRGM pin on the LTC7820IUFD#PBF?
The HYS_PRGM pin on the LTC7820IUFD#PBF programs the hysteresis and asymmetry of the VLOW_SENSE window comparator, which monitors the relationship between VLOW_SENSE and VHIGH_SENSE/2. A resistor from HYS_PRGM to GND sets two independent thresholds - one for rising VLOW_SENSE and another for falling - allowing designers to tune fault sensitivity for capacitor tolerance, temperature drift, and load transient behavior. This programmability ensures reliable operation across production variations without requiring layout changes to the LTC7820IUFD#PBF circuit.
Can the LTC7820IUFD#PBF be used without external MOSFETs?
No, the LTC7820IUFD#PBF cannot be used without external MOSFETs. It is a controller-only IC that provides four high-current gate drivers (G1–G4) but contains no power switches. External N-channel MOSFETs are mandatory for all supported topologies - typically 100V devices for 72V-input divider applications. The LTC7820IUFD#PBF's gate drive strength, timing control, and protection logic are specifically designed to interface with discrete MOSFETs, and no monolithic alternative exists within this product family.
What is the role of the TIMER pin in LTC7820IUFD#PBF operation?
The TIMER pin on the LTC7820IUFD#PBF serves a dual function: it sets the duration of the pre-balance phase during startup (where ISENSE+ sources 93mA to VLOW to equalize flying capacitors) and defines the retry timeout after a fault-induced shutdown. A capacitor from TIMER to GND determines both intervals - larger values increase pre-charge time and fault recovery delay. This single-pin configuration simplifies design while enabling robust start-up into heavy capacitive loads and controlled response to overcurrent or overvoltage events in the LTC7820IUFD#PBF system.
LTC7820IUFD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Up, Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck, Boost
- Number of Outputs:
- 1
- Output Phases:
- 2
- Voltage - Supply (Vcc/Vdd):
- 6V ~ 72V
- Frequency - Switching:
- 100kHz ~ 1MHz
- Duty Cycle (Max):
- 50%
- 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:
- 28-QFN (4x5)
LTC7820IUFD#PBF FAQ
1.How can I place an order for LTC7820IUFD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC7820IUFD#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 LTC7820IUFD#PBF reliable?
The price and inventory of LTC7820IUFD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC7820IUFD#PBF is usually 5 days.
3.What payment methods are accepted for LTC7820IUFD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC7820IUFD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC7820IUFD#PBF?
LTC7820IUFD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC7820IUFD#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 LTC7820IUFD#PBF?
For technical support, including LTC7820IUFD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC7820IUFD#PBF requirements.
6.How does Aetrix verify that LTC7820IUFD#PBF is sourced from the original manufacturer or authorized distributors?
All LTC7820IUFD#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 LTC7820IUFD#PBF meets industry standards.
7.What is the process for return or replacement of LTC7820IUFD#PBF?
All LTC7820IUFD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC7820IUFD#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 LTC7820IUFD#PBF part is unused and in its original packaging.
Return procedure for LTC7820IUFD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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