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Analog Devices Inc. LTC7805RUFDM#PBF
- Part No.:
- LTC7805RUFDM#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LTC7805RUFDM#PBF.pdf
- Description:
- 40V DUAL LOW IQ, 100% DC SYNC BU
- Quantity:
- Payment:
- Shipping:
Inventory:4,068
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Product details
Overview
LTC7805RUFDM#PBF from Analog Devices is a dual-phase, synchronous step-down DC/DC controller driving all-N-channel MOSFETs. It operates from 4.5V to 40V input, delivers 0.8V–40V output per channel, supports 100kHz–3MHz programmable switching frequency, and achieves 14μA no-load quiescent current-enabling high-efficiency power conversion in automotive infotainment and industrial 24V rail regulation.
For engineers reviewing the LTC7805RUFDM#PBF datasheet, LTC7805RUFDM#PBF pinout, LTC7805RUFDM#PBF application, or LTC7805RUFDM#PBF equivalent, key selection criteria include out-of-phase dual-channel operation for reduced input capacitance, spread spectrum EMI reduction, OPTI-LOOP compensation for wide output capacitor/ESR tolerance, 100% duty cycle capability, and AEC-Q100 qualification for automotive use.
Technical Context
The LTC7805RUFDM#PBF implements constant-frequency peak current-mode control with two independent channels operating 180° out of phase. Each channel features separate ITH error amplifier outputs, VFB feedback inputs, TRACK/SS soft-start pins, and dedicated SENSE+/– current sensing paths supporting RSENSE or DCR sensing.
Its architecture integrates dual gate drivers (TG/BG) with 0.6Ω pull-down and 1.2Ω pull-up on-resistance, internal 5.4V INTVCC LDO powered from VIN or EXTVCC, and a phase-lockable oscillator with spread spectrum dithering enabled via PLLIN/SPREAD pin-allowing synchronization to external clocks or EMI reduction without external components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 40V - supports direct connection to 12V/24V/36V industrial and automotive battery rails without pre-regulation. |
| Output Voltage Range | 0.8V to 40V per channel - enables flexible generation of logic, analog, and interface rails from single high-voltage source. |
| No-Load Quiescent Current | 14μA (14V→3.3V, Ch1 active) - extends runtime in always-on battery-powered systems such as telematics modules. |
| Switching Frequency | 100kHz to 3MHz, programmable via FREQ pin resistor - allows optimization of size (high-freq) vs. efficiency (low-freq) and EMI compliance. |
| Reference Voltage | Precision 0.8V ±12mV over –40°C to 150°C - ensures stable output regulation across automotive temperature extremes. |
| Duty Cycle Capability | 100% - supports PassThru™ operation for low-dropout linear-like behavior during input voltage sag. |
| EMI Reduction | Integrated spread spectrum modulation - reduces peak conducted/radiated noise without external filters or layout changes. |
Pinout & Package
Package: 28-lead 4mm × 5mm QFN with exposed thermal pad (Pin 29 = GND), rated for –40°C to 150°C junction temperature and qualified to AEC-Q100 Grade 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SENSE1+, SENSE2+ | Differential current sense positive inputs | Connect to high-side of RSENSE or DCR network; set current limit threshold jointly with ITH voltage and offset. |
| SENSE1–, SENSE2– | Differential current sense negative inputs | Supply bias current when ≥3.2V; enable VIN-current reduction in sleep mode by sourcing quiescent current from output rail. |
| TG1, TG2 / BG1, BG2 | Top/bottom N-MOSFET gate drivers | TG swing = INTVCC + SW node; BG swing = 0V to INTVCC; support fast switching with 10ns/20ns rise/fall times into 3.3nF load. |
| BOOST1, BOOST2 | Floating bootstrap supplies | Charge pump and diode-connected path recharges boot caps; internal charge pump activates below UVLO to sustain 100% duty cycle. |
| VFB1, VFB2 | Feedback voltage inputs | Regulate output to 0.8V reference; tie VFB2 to INTVCC for 2-phase single-output configuration sharing VFB1/ITH1/TRACK/SS1. |
| PLLIN/SPREAD | Sync input / spread spectrum control | Apply external clock for phase-locking; tie to INTVCC for spread spectrum; tie to GND to disable dithering. |
| RUN1, RUN2 | Independent channel enable | Disable individual channel at <1.1V; full shutdown at both <0.7V → 1.5μA IQ; tolerate up to 40V absolute max. |
| MODE | Light-load operation mode select | GND = Burst Mode; INTVCC = forced continuous; 1.2V–(INTVCC–1.3V) = pulse-skipping - selectable per system noise/efficiency trade-off. |
Key Features
| Feature | Design Value |
|---|---|
| Out-of-phase dual controllers | Reduces RMS input ripple current by ~70% vs. in-phase operation, cutting required input capacitance and easing EMI filter design. |
| OPTI-LOOP compensation | Enables stable loop response across 10μF–1000μF ceramic/tantalum output capacitors with 1mΩ–100mΩ ESR - eliminates need for custom compensation per BOM change. |
| Spread spectrum modulation | ±10% frequency dithering reduces peak radiated emissions by >10dB in 100kHz–10MHz band - simplifies CISPR 25 Class 5 compliance for automotive designs. |
| PassThru™ 100% duty cycle | Maintains regulated output during input voltage sags down to VOUT + dropout, avoiding brownout resets in stop-start vehicle systems. |
| AEC-Q100 Grade 1 qualification | Validated for –40°C to 150°C operation with HTOL, TC, ESD, and AC/DC stress testing - meets functional safety requirements for ASIL-B applications. |
Applications
| Automotive Infotainment Power | Industrial 24V DC-DC Conversion |
|---|---|
Use Scenario: Powering SoC, DDR memory, and display interfaces in head units with 12V battery input and strict EMI limits. IC Role / Device Role / Timing Role: Dual-phase buck controller generating 1.1V/1.8V/3.3V/5V rails with synchronized switching and spread spectrum to meet CISPR 25 Class 5. Use Value: 14μA quiescent current prevents battery drain during vehicle sleep mode; 100% duty cycle avoids reset during engine cranking. | Use Scenario: Converting 24V factory bus to isolated 5V/12V rails for PLC I/O modules requiring high reliability and thermal robustness. IC Role / Device Role / Timing Role: High-input-voltage controller driving discrete MOSFETs with out-of-phase operation to minimize input capacitor stress and board area. Use Value: AEC-Q100 qualification ensures long-term stability in harsh environments; OPTI-LOOP accommodates aging electrolytic output capacitors. |
| Avionics Power Management | Telecom Remote Radio Unit |
Use Scenario: Regulating 28V aircraft bus to 3.3V/5V for flight control sensors and data acquisition units with stringent MTBF requirements. IC Role / Device Role / Timing Role: Dual-channel controller with independent RUN pins enabling fault-isolated power domains and graceful degradation. Use Value: 150°C junction rating supports conduction-cooled enclosures; low shutdown IQ (1.5μA) preserves backup battery life. | Use Scenario: Generating 12V/24V intermediate rails from 48V telecom rectifier in outdoor base station radios exposed to wide ambient temperatures. IC Role / Device Role / Timing Role: High-efficiency synchronous controller using EXTVCC to derive INTVCC from its own output, reducing total system losses. Use Value: Spread spectrum and programmable frequency allow tuning to avoid narrowband interference from RF transceivers; RSENSE/DCR flexibility supports cost-optimized layouts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-phase synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP2918GL-Z | Single-chip dual-phase controller with integrated MOSFETs; fixed 500kHz/1MHz freq; no spread spectrum; 2.5V–24V input. | Suitable for space-constrained, lower-power (<20A) applications where integration outweighs input voltage range and EMI flexibility. | Select MP2918GL-Z only if input ≤24V and integrated FETs meet RDS(on)/thermal needs; not drop-in due to different pinout and lack of 100% duty cycle. |
| ISL78234ARZ-T7A | Automotive-qualified dual-phase controller; 3.1V–40V input; 1.2V reference; no spread spectrum; requires external clock for sync. | Targeted at ASIL-B ADAS cameras and radar where deterministic timing dominates over EMI reduction. | Choose ISL78234ARZ-T7A when deterministic jitter-free operation is mandatory and spread spectrum is undesirable; verify PGOOD timing compatibility. |
Compared with MP2918GL-Z and ISL78234ARZ-T7A, the LTC7805RUFDM#PBF uniquely combines 40V input, 0.8V reference, spread spectrum, and 100% duty cycle in a single AEC-Q100 package-making it optimal for high-reliability automotive and industrial systems demanding wide input range and robust EMI performance.
Availability
LTC7805RUFDM#PBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial 24V DC-DC conversion, and avionics power management requiring stable component supply across extended temperature and lifecycle demands.
Supply support for LTC7805RUFDM#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, communications, and automotive markets.
The LTC7805RUFDM#PBF belongs to the Power by Linear™ controller family, engineered for high-efficiency, high-reliability DC-DC conversion in automotive, industrial, and aerospace applications where input voltage range, thermal robustness, and EMI compliance are critical.
FAQ
What is the maximum input voltage rating for the LTC7805RUFDM#PBF?
The LTC7805RUFDM#PBF has an absolute maximum input supply voltage (VIN) rating of 40V, with recommended operating range from 4.5V to 40V. Exceeding 40V may cause permanent damage. This rating enables direct connection to 24V and 36V industrial buses and 12V/24V automotive systems including cranking transients.
How does the MODE pin configure light-load operation on the LTC7805RUFDM#PBF?
The MODE pin on the LTC7805RUFDM#PBF selects among three light-load modes: grounding enables Burst Mode (highest efficiency, lowest IQ), tying to INTVCC forces continuous conduction, and applying 1.2V–(INTVCC–1.3V) enables pulse-skipping. An internal 100kΩ pull-down defaults to Burst Mode when floating, ensuring safe startup without external bias.
Can the LTC7805RUFDM#PBF operate with 100% duty cycle, and what is its purpose?
Yes, the LTC7805RUFDM#PBF supports true 100% duty cycle operation via its PassThru™ feature. When input voltage approaches the output level, the top MOSFET remains continuously on, maintaining regulation without dropout-critical for automotive stop-start systems where battery voltage can sag to 6V while powering 5V loads.
What thermal performance can be expected from the LTC7805RUFDM#PBF in a typical 4-layer PCB layout?
In a standard 4-layer PCB with 2oz copper and full thermal pad soldering, the LTC7805RUFDM#PBF exhibits θJA = 43°C/W. At 150°C max junction temperature and 25°C ambient, it supports ~2.9W dissipation before thermal limiting. Derating is required above 85°C ambient; thermal shutdown activates at TJ = 150°C to protect the device.
Is the LTC7805RUFDM#PBF pin-compatible with other members of the LTC78xx controller family?
No, the LTC7805RUFDM#PBF is not pin-compatible with earlier LTC78xx controllers (e.g., LTC7801/LTC7803). Its 28-pin QFN layout, dual independent SENSE+/– pairs, PLLIN/SPREAD functionality, and dedicated EXTVCC/INTVCC pins reflect a distinct architecture optimized for dual-phase out-of-phase operation and spread spectrum-requiring unique PCB layout.
LTC7805RUFDM#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Output Type:
- Adjustable
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Number of Outputs:
- 2
- Output Phases:
- 2
- Voltage - Supply (Vcc/Vdd):
- 4.5V ~ 40V
- Frequency - Switching:
- 100kHz ~ 3MHz
- Duty Cycle (Max):
- 100%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Power Good
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount, Wettable Flank
- Supplier Device Package:
- 28-QFN (4x5)
LTC7805RUFDM#PBF FAQ
1.How can I place an order for LTC7805RUFDM#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC7805RUFDM#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 LTC7805RUFDM#PBF reliable?
The price and inventory of LTC7805RUFDM#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC7805RUFDM#PBF is usually 5 days.
3.What payment methods are accepted for LTC7805RUFDM#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC7805RUFDM#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC7805RUFDM#PBF?
LTC7805RUFDM#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC7805RUFDM#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 LTC7805RUFDM#PBF?
For technical support, including LTC7805RUFDM#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC7805RUFDM#PBF requirements.
6.How does Aetrix verify that LTC7805RUFDM#PBF is sourced from the original manufacturer or authorized distributors?
All LTC7805RUFDM#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 LTC7805RUFDM#PBF meets industry standards.
7.What is the process for return or replacement of LTC7805RUFDM#PBF?
All LTC7805RUFDM#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC7805RUFDM#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 LTC7805RUFDM#PBF part is unused and in its original packaging.
Return procedure for LTC7805RUFDM#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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