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Analog Devices Inc. LTC7820EUFD#PBF
- Part No.:
- LTC7820EUFD#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LTC7820EUFD#PBF.pdf
- Description:
- IC CHARGE PUMP DC/DC CTRLR 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,608
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Product details
Overview
LTC7820EUFD#PBF from Analog Devices is a fixed-ratio, high-voltage switched-capacitor DC/DC controller for non-isolated bus conversion. It drives four external N-channel MOSFETs to implement 2:1 voltage divider (VIN ≤ 72V), 1:2 doubler (VIN ≤ 36V), or 1:1 inverter (VIN ≤ 36V) topologies with 50% duty-cycle switching, achieving >99% peak efficiency at 5A output and supporting 500W+ power density in compact 4mm × 5mm QFN packages.
For engineers reviewing the LTC7820EUFD#PBF datasheet, LTC7820EUFD#PBF pinout, LTC7820EUFD#PBF application, or LTC7820EUFD#PBF equivalent, key selection criteria include its programmable 100kHz–1MHz switching frequency, high-side current sensing with 50mV overcurrent threshold, VHIGH_SENSE/VLOW_SENSE Kelvin sensing architecture, EXTVCC-supported efficiency optimization, and fault-protected operation with timer-based retry.
Technical Context
The LTC7820EUFD#PBF operates as an open-loop, constant-frequency charge pump controller-no output voltage feedback loop is implemented. It relies on precise gate timing (G1/G2 tD = 50ns, G3/G4 tD = 60ns) and pre-balancing circuitry to ensure soft-start into steady-state capacitor voltage division without inrush damage.
Its quad floating gate drivers (G1–G4) support bootstrapped operation with BOOST1–BOOST3 supplies, enabling high-side N-MOSFET control in 72V-input divider configurations. The IC integrates input current sensing (ISENSE+/–), dual-window VLOW_SENSE monitoring (programmable via HYS_PRGM), and independent UVLO (5.05V INTVCC rising threshold) and PGOOD logic tied to UV pin status.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Max (Divider) | 72V - Enables direct step-down from 48V/60V industrial or telecom intermediate buses without pre-regulation. |
| VIN Max (Doubler/Inverter) | 36V - Supports 12V-to-24V boost or 12V-to-±12V inversion in space-constrained systems. |
| Switching Frequency | 100kHz–1MHz - Programmable via FREQ pin current (10µA sink); lower frequencies reduce MOSFET switching loss, higher frequencies shrink flying capacitors. |
| Overcurrent Threshold | 50mV (ISENSE+ – ISENSE–) - Sets current limit with ±5mV tolerance; enables accurate high-side sensing using 5mΩ RSENSE for 10A full-scale. |
| INTVCC Regulation | 5.6V ±0.3V (no load, VCC = 6–72V) - Powers internal logic and gate drivers; EXTVCC switchover at 6.5V improves thermal performance above 15V VCC. |
| Operating Temp Range | –40°C to +125°C junction - Qualified for industrial and telecom equipment with validated performance across full range. |
| Package | 28-pin 4mm × 5mm QFN with exposed pad (Pin 29 = GND) - Thermally enhanced layout supports >500W with θJC = 3.4°C/W. |
Pinout & Package
Package: 28-lead (4mm × 5mm) plastic QFN with exposed thermal pad (Pin 29 = GND). Pin spacing optimized for high-voltage isolation; NC pins (2, 10, 13, 26) provide creepage between adjacent HV nodes.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VHIGH_SENSE (1) | Kelvin sense input | Monitors drain voltage of top MOSFET (M1); enables accurate ratio control without PCB trace resistance error. |
| G1 (24) | Floating gate driver output | Drives uppermost N-MOSFET (M1); swing = BOOST1 to SW1; requires external bootstrap diode/capacitor. |
| HYS_PRGM (3) | Window comparator programming | Sinks 10µA; resistor to GND sets VLOW_SENSE fault window thresholds (e.g., ±0.6V around VHIGH_SENSE/2). |
| TIMER (4) | Pre-balance & fault timer | Capacitor to GND sets time for VLOW pre-charge at startup and short-circuit retry interval. |
| FREQ (5) | Frequency programming | Sinks precision 10µA; resistor to GND sets fSW linearly from 100kHz to 1MHz (e.g., 100kΩ → 483kHz). |
| RUN (6) | Enable control input | 1.22V threshold with 80mV hysteresis; 1µA pull-up during start-up; controls soft enable/disable sequencing. |
| PGOOD (7) | Open-drain status output | Pulled low during UV condition (UV pin < 1V), FAULT assertion, or RUN = low; compatible with 45V pull-ups. |
| UV (8) | Undervoltage monitor input | Compares to 1.01V reference; used to assert PGOOD when system input falls below safe operating level. |
| FAULT (9) | Open-drain fault indicator | Pulled low on VLOW_SENSE out-of-window, ISENSE+–ISENSE– > 50mV, or INTVCC UVLO; supports external disconnect FET control up to 80V. |
| NC (10) | No connection | Electrically isolated; must remain floating to maintain HV creepage between VCC and BOOST2. |
| EXTVCC (11) | External bias input | Enables secondary LDO for INTVCC when >6.5V; reduces IC self-heating vs. VCC-only supply above 15V. |
| INTVCC (12) | Internal LDO output | 5.6V ±0.3V regulated supply for logic and drivers; requires ≥4.7µF ceramic bypass to GND. |
| NC (13) | No connection | Isolation gap between INTVCC and BOOST1; must remain unconnected. |
| VCC (14) | Main bias supply | 6V–72V input to primary INTVCC LDO; bypass capacitor mandatory for stability and noise immunity. |
| G4 (15) | Bottom synchronous driver | Ground-referenced gate drive (0V to INTVCC); drives low-side N-MOSFET (M4) in divider/doubler/inverter. |
| SW3 (16) | Switch node | Connects to source of M3 and drain of M4; node swings between VLOW and BOOST3 voltage. |
| G3 (17) | Floating gate driver output | Drives third MOSFET (M3); swing = BOOST3 to SW3; requires dedicated bootstrap capacitor. |
| BOOST3 (18) | Bootstrap supply | Connects to capacitor between SW3 and VLOW; provides gate drive voltage for G3 during high-side conduction. |
| VLOW_SENSE (19) | Kelvin sense input | Monitors VLOW node voltage; compared against programmable window centered at VHIGH_SENSE/2. |
| VLOW (20) | Half-supply output node | Output of voltage divider (or input of doubler/inverter); connects to CVLOW capacitor and M2/M3 sources. |
| G2 (21) | Floating gate driver output | Drives second MOSFET (M2); swing = BOOST2 to VLOW; requires bootstrap cap between BOOST2 and VLOW. |
| BOOST2 (22) | Bootstrap supply | Capacitor connects between BOOST2 and VLOW; supplies gate drive for G2 during M2 conduction. |
| BOOST1 (23) | Bootstrap supply | Capacitor connects between BOOST1 and SW1; supplies gate drive for G1 during M1 conduction. |
| SW1 (25) | Switch node | Connects to drain of M1 and source of M2; node swings between VHIGH_SENSE and BOOST1. |
| ISENSE+ (27) | Current sense positive input | Kelvin-connected to top MOSFET drain; sources 93mA to VLOW during pre-balance phase in divider mode. |
| ISENSE– (28) | Current sense negative input | Kelvin-connected to RSENSE ground side; differential input with 50mV overcurrent threshold. |
| GND (29) | Signal & power ground | Exposed thermal pad; must be soldered to PCB ground plane for thermal and EMI performance. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed-ratio charge pump topology | Eliminates magnetic components-enables ultra-thin, high-power-density bus converters with no inductors or transformers. |
| Programmable soft-start pre-balance | TIMER pin capacitor controls VLOW ramp time to VHIGH_SENSE/2 before switching begins, preventing capacitor inrush damage. |
| High-side current sensing | ISENSE+/– inputs support Kelvin-connected RSENSE at M1 drain-avoids ground bounce errors and enables accurate overcurrent protection. |
| Multi-mode fault protection | Simultaneous monitoring of VLOW_SENSE window, ISENSE differential, INTVCC UVLO, and thermal shutdown with configurable retry timing. |
| EXTVCC efficiency enhancement | Secondary LDO activated when EXTVCC > 6.5V reduces IC power dissipation by >30% at high VCC, lowering junction temperature. |
| High-voltage pin spacing | NC pins (2, 10, 13, 26) and wide pitch isolate VCC/BOOST1/BOOST2 nodes-supports 72V operation with reinforced creepage in compact QFN. |
Applications
| Telecom Intermediate Bus Conversion | Industrial 48V-to-24V Power Distribution |
|---|---|
|
Use Scenario: Converting 48V backplane supply to 24V intermediate bus in 1RU telecom servers with strict height constraints. IC Role / Device Role / Timing Role: Fixed-ratio charge pump controller driving discrete N-MOSFETs in 2:1 voltage divider configuration; no feedback loop required. Use Value: Achieves >99% efficiency at 10A while eliminating inductors-reducing board area by 40% and enabling 8mm max profile. |
Use Scenario: Distributed 48V-to-24V conversion across PLC I/O modules where EMI and thermal management are critical. IC Role / Device Role / Timing Role: Open-loop switched-capacitor controller with programmable 250kHz switching frequency and EXTVCC bias for low-temperature rise. Use Value: Soft-switching reduces conducted EMI by 15dB vs. hard-switched buck; thermal pad ensures <85°C junction at full load. |
| Data Center Voltage Doubler | Test Equipment Bipolar Supply Generation |
|
Use Scenario: Generating 24V from 12V input in high-density server rack power shelves requiring minimal component count. IC Role / Device Role / Timing Role: Configured as 1:2 voltage doubler with G1–G4 driving external MOSFETs; VLOW pin becomes input, SW1 becomes output. Use Value: Delivers 20A at 24V with <1.2W total loss-outperforms equivalent buck-boost ICs by 3.5% efficiency at 1MHz. |
Use Scenario: Creating ±12V rails from single 12V supply in automated test equipment with tight regulation and fast transient response. IC Role / Device Role / Timing Role: Operated as 1:1 inverter with GND referenced to negative output; VLOW pin supplies negative rail, GND serves as return. Use Value: Symmetrical ±12V outputs with <50mV ripple at 500kHz; VLOW_SENSE monitoring ensures balanced rail tracking within ±1.5%. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar fixed-ratio switched-capacitor controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC7821IUFD#PBF | Same pinout and function but rated for –40°C to 125°C industrial temp grade (vs. LTC7820EUFD#PBF's 0°C to 85°C commercial grade). | Required for extended temperature deployments; identical electrical specs and layout compatibility. | Select LTC7821IUFD#PBF when ambient operating temperature exceeds 85°C or automotive qualification is needed. |
| MPQ4332GJ-AEC1-P | Automotive-grade 2:1 charge pump controller in 20-pin QFN; integrates MOSFETs (no external FETs), max VIN = 36V, fixed 500kHz fSW. | Lower voltage, integrated solution for infotainment systems; lacks programmable frequency, EXTVCC, or VLOW_SENSE windowing. | Choose MPQ4332GJ-AEC1-P only for AEC-Q100-compliant 12V/24V automotive applications where integration outweighs flexibility. |
Compared with LTC7821IUFD#PBF, the LTC7820EUFD#PBF offers identical functionality at lower cost for commercial-temperature designs, while MPQ4332GJ-AEC1-P trades configurability for AEC-Q100 compliance and monolithic integration-making it unsuitable for 72V telecom or programmable-frequency industrial use cases.
Availability
LTC7820EUFD#PBF is available at Aetrix Electronics and suitable for telecom intermediate bus converters, industrial 48V distributed power systems, and test equipment bipolar supplies requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.
Supply support for LTC7820EUFD#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 industrial, communications, automotive, and aerospace markets with precision power, signal chain, and RF solutions.
The LTC7820EUFD#PBF belongs to ADI's Power by Linear™ family of high-efficiency, high-voltage DC/DC controllers-designed specifically for non-isolated, high-power-density bus conversion where magnetics are impractical or prohibited.
FAQ
What is the maximum input voltage supported by the LTC7820EUFD#PBF in voltage divider mode?
The LTC7820EUFD#PBF supports up to 72V input in 2:1 voltage divider configuration, as confirmed by Absolute Maximum Ratings (VCC, VHIGH_SENSE ≤ 80V) and Electrical Characteristics (VIN Max for Divider = 72V). This enables direct conversion from 48V or 60V telecom and industrial intermediate buses without pre-regulation stages. Operation above 72V risks permanent damage per datasheet limits.
Does the LTC7820EUFD#PBF require an output voltage feedback loop?
No, the LTC7820EUFD#PBF operates as an open-loop fixed-ratio controller-it does not regulate output voltage via feedback. Instead, it relies on precise MOSFET timing and capacitor voltage division to maintain VLOW ≈ VHIGH_SENSE/2 in divider mode. Output regulation depends entirely on component matching and load stability; closed-loop compensation is not implemented or supported in the LTC7820EUFD#PBF.
How is overcurrent protection implemented in the LTC7820EUFD#PBF?
The LTC7820EUFD#PBF implements high-side overcurrent protection using differential sensing at ISENSE+ and ISENSE– pins, with a fixed 50mV threshold (±5mV tolerance). When the voltage difference exceeds this value, the FAULT pin is pulled low and switching halts. The ISENSE+ pin also sources 93mA to VLOW during pre-balance, confirming active current path integrity before startup-both functions are verified in the Electrical Characteristics table and Application Information section.
Can the LTC7820EUFD#PBF be used in inverting configurations?
Yes, the LTC7820EUFD#PBF supports 1:1 inverting operation with input applied between VHIGH_SENSE and VLOW, delivering inverted output at GND relative to VLOW. The datasheet confirms this in the DESCRIPTION section ("1:1 inverting ratio from an input voltage up to 36V") and Figure 9 (24V-to–24V Inverter). VLOW_SENSE monitoring remains active to ensure proper rail balancing, and all fault protections apply identically.
What is the purpose of the EXTVCC pin on the LTC7820EUFD#PBF?
The EXTVCC pin on the LTC7820EUFD#PBF enables a secondary 5.6V LDO that powers INTVCC when EXTVCC > 6.5V and VCC > 7V. This reduces IC self-heating by bypassing the primary VCC-to-INTVCC regulator-critical for efficiency optimization above 15V VCC. Datasheet Section "INTVCC Regulator" specifies ±2% load regulation and 0.5% line regulation under EXTVCC bias, confirming its role in thermal management.
LTC7820EUFD#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
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-QFN (4x5)
LTC7820EUFD#PBF FAQ
1.How can I place an order for LTC7820EUFD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC7820EUFD#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 LTC7820EUFD#PBF reliable?
The price and inventory of LTC7820EUFD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC7820EUFD#PBF is usually 5 days.
3.What payment methods are accepted for LTC7820EUFD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC7820EUFD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC7820EUFD#PBF?
LTC7820EUFD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC7820EUFD#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 LTC7820EUFD#PBF?
For technical support, including LTC7820EUFD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC7820EUFD#PBF requirements.
6.How does Aetrix verify that LTC7820EUFD#PBF is sourced from the original manufacturer or authorized distributors?
All LTC7820EUFD#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 LTC7820EUFD#PBF meets industry standards.
7.What is the process for return or replacement of LTC7820EUFD#PBF?
All LTC7820EUFD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC7820EUFD#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 LTC7820EUFD#PBF part is unused and in its original packaging.
Return procedure for LTC7820EUFD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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