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Analog Devices Inc. LTC7817EUHF#PBF
- Part No.:
- LTC7817EUHF#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 38-WFQFN Exposed Pad
- Datasheet:
-
LTC7817EUHF#PBF.pdf
- Description:
- 40V, 8UA IQ, 3MHZ, TRPLE BCKBST
- Quantity:
- Payment:
- Shipping:
Inventory:187
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Product details
Overview
LTC7817EUHF#PBF from Analog Devices is a high-performance triple-output synchronous DC/DC controller integrating two buck and one boost stages, driving all-N-channel MOSFETs. It operates from 4.5V–40V input (or down to 1V post-startup), delivers up to 40V on buck/boost outputs, supports 3MHz switching, and achieves 14μA no-load IQ - enabling robust cold-crank operation in automotive start-stop systems.
For engineers reviewing the LTC7817EUHF#PBF datasheet, LTC7817EUHF#PBF pinout, LTC7817EUHF#PBF application, or LTC7817EUHF#PBF equivalent, key selection considerations include its AEC-Q100 qualification, OPTI-LOOP® compensation for wide output capacitor/ESR tolerance, PassThru™ boost capability, and independent RUN/SS/ITH pins per channel for flexible sequencing and transient optimization.
Technical Context
The LTC7817EUHF#PBF implements a constant-frequency peak current-mode architecture with phase-controlled interleaving: Buck channels 1 and 2 operate 180° out-of-phase to reduce input ripple, while boost channel 3 synchronizes with channel 1. Each channel features independent ITH-based current limit programming and dedicated VFB references (0.8V for bucks, 1.2V for boost).
Its dual-bias architecture allows operation from VBIAS (4.5V–40V) or auxiliary supplies (e.g., boost output), enabling sub-1V VIN operation after startup. The controller integrates three gate drivers (TG/BG per channel), internal 5.1V INTVCC LDO, EXTVCC switchover LDO, and precision voltage references with ±1.5% initial accuracy over temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology | Dual buck + single boost synchronous controller - enables compact 3-rail power architecture with shared gate drive resources. |
| Input Voltage Range | 4.5V–40V (VBIAS); extends to 1V post-startup when biased from boost output - supports automotive cold-crank and wide-input industrial systems. |
| Switching Frequency | 100kHz–3MHz programmable via FREQ pin resistor; phase-lockable up to 3MHz - allows EMI optimization and high-density layout. |
| No-Load Quiescent Current | 14μA (14V→3.3V, Channel 1 active) - extends battery runtime in always-on vehicle modules. |
| Feedback Reference Voltages | 0.8V ±1.5% (buck), 1.2V ±1.5% (boost) - ensures tight output regulation across temperature and load. |
| Output Voltage Range | Buck: 0.8V–40V; Boost: up to 40V - supports diverse rail requirements including 3.3V, 5V, 12V, and programmable 8V/10V boost outputs. |
| Package | 38-lead 5mm × 7mm QFN with exposed PGND pad - provides low thermal resistance (θJA = 34.7°C/W) and high-current grounding for automotive reliability. |
Pinout & Package
Package: 38-lead plastic QFN (5mm × 7mm), exposed thermal pad (Pin 39 = PGND), rated for –40°C to 125°C junction temperature.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FREQ (1) | Oscillator frequency control | Resistor-to-ground sets 100kHz–3MHz; GND = 380kHz, INTVCC = 2.25MHz - enables precise EMI tuning without external clock source. |
| PLLIN/MODE (2) | Synchronization input / light-load mode select | Accepts external clock for phase-locking; floating = Burst Mode, INTVCC = forced continuous, 100kΩ-to-INTVCC = pulse-skipping - gives full control over efficiency vs. noise trade-offs. |
| SS3 (3) | Boost soft-start/tracking input | 12.5µA pull-up; capacitor-to-ground sets ramp time (1ms/10nF) - prevents inrush during boost startup and enables tracking of other rails. |
| SENSE3+ (4) | Boost current sense positive input | Supplies current to comparator when > INTVCC - enables accurate RSENSE or DCR sensing for boost overcurrent protection. |
| SENSE3– (5) | Boost current sense negative input | Current sink when > INTVCC; bias current sourced from SENSE1– at ≥3.2V - reduces system IQ by shifting quiescent current path. |
| VFB3 (6) | Boost feedback input | Regulated to 1.2V reference when VPRG3 floating; tied directly to VOUT3 when VPRG3 = GND/INTVCC for fixed 8V/10V - simplifies design for common automotive boost rails. |
| ITH3 (7) | Boost error amplifier output | Controls current limit threshold and loop compensation - connects to RC network for stability across wide output capacitance range. |
| SGND (8) | Small-signal ground reference | Must be routed separately from PGND to avoid noise coupling into sensitive analog circuits - critical for stable current-mode control. |
| RUN1 (9) | Buck channel 1 enable | Threshold = 1.2V rising; <0.7V disables entire IC - allows independent sequencing and fault shutdown per rail. |
| RUN2 (10) | Buck channel 2 enable | Same threshold as RUN1; supports staggered startup or independent rail control - essential for multi-rail power sequencing. |
| RUN3 (11) | Boost channel 3 enable | Same threshold as RUN1; enables boost only when needed - improves system efficiency during low-power states. |
| SENSE2– (12) | Buck channel 2 current sense negative | Supplies comparator current when > INTVCC - matches SENSE1– behavior for consistent channel performance. |
| SENSE2+ (13) | Buck channel 2 current sense positive | Differential input for RSENSE/DCR sensing - used with SENSE2– to set channel 2 current limit independently. |
| VFB2 (14) | Buck channel 2 feedback input | Tie to INTVCC for two-phase single-output configuration sharing VFB1/ITH1/SS1 - reduces component count for high-current 5V/3.3V rails. |
| ITH2 (15) | Buck channel 2 error amplifier output | Compensation point for channel 2 loop - allows independent tuning of transient response for asymmetric loads. |
| TRACK/SS2 (16) | Buck channel 2 tracking/soft-start | 12.5µA pull-up; capacitor-to-ground sets ramp (0.65ms/10nF); resistor divider enables tracking - supports coordinated startup with processor cores or FPGAs. |
| VPRG3 (17) | Boost output voltage programming | Float = adjustable via VFB3; GND = 8V fixed; INTVCC = 10V fixed - eliminates external resistors for standard automotive boost voltages. |
| TG2 (18) | Buck channel 2 top gate driver output | Floating N-channel driver with INTVCC swing above SW2 - drives high-side MOSFET with fast 25ns rise/fall times. |
| SW2 (19) | Buck channel 2 switch node | Connects to inductor and BOOST2 capacitor - forms high-frequency switching node requiring tight layout and low-inductance routing. |
| BOOST2 (20) | Buck channel 2 bootstrap supply | Capacitor between BOOST2 and SW2 generates floating gate drive voltage - Schottky diode to INTVCC maintains charge during low-duty cycles. |
| BG2 (21) | Buck channel 2 bottom gate driver output | GND-to-INTVCC driver for synchronous rectifier - complements TG2 for high-efficiency buck conversion. |
| INTVCC (22) | Internal 5.1V LDO output | Powers control circuitry and gate drivers; requires ≥4.7µF ceramic decoupling - serves as bias source for EXTVCC switchover and SENSE pins. |
| EXTVCC (23) | External bias input for INTVCC LDO | Switchover at 4.7V; bypasses VBIAS LDO when active - reduces total system IQ by sourcing bias from regulated output rails. |
| VBIAS (24) | Main bias supply input | 4.5V–40V operating range; powers internal LDO and logic - primary supply for standalone operation or backup when EXTVCC is inactive. |
| BG3 (25) | Boost channel 3 bottom gate driver output | GND-to-INTVCC driver for synchronous rectifier - enables 100% duty-cycle PassThru™ operation during cold crank. |
| BOOST3 (26) | Boost channel 3 bootstrap supply | Capacitor between BOOST3 and SW3 generates floating gate drive; swing = INTVCC to (VOUT3 + INTVCC) - supports high-voltage boost topologies. |
| TG3 (27) | Boost channel 3 top gate driver output | Floating N-channel driver referenced to SW3 - drives high-side MOSFET in boost configuration with matched timing to BG3. |
| SW3 (28) | Boost channel 3 switch node | Connects to inductor and BOOST3 capacitor - high dv/dt node requiring careful PCB layout to minimize EMI and shoot-through risk. |
| BG1 (29) | Buck channel 1 bottom gate driver output | GND-to-INTVCC driver - provides synchronous rectification for highest efficiency in buck stage 1. |
| BOOST1 (30) | Buck channel 1 bootstrap supply | Capacitor between BOOST1 and SW1; Schottky diode to INTVCC - ensures reliable high-side drive across full duty cycle range. |
| SW1 (31) | Buck channel 1 switch node | Primary switching node for first buck stage - interfaces with input capacitor, inductor, and synchronous rectifier. |
| TG1 (32) | Buck channel 1 top gate driver output | Floating N-channel driver with fast 25ns transitions - enables high-frequency operation up to 3MHz with minimal dead-time loss. |
| PGOOD1 (33) | Power-good indicator for buck 1 | Open-drain output monitoring VFB1; asserts low if VOUT1 deviates >±10% - provides system-level fault signaling for microcontrollers or PMICs. |
| TRACK/SS1 (34) | Buck channel 1 tracking/soft-start | 12.5µA pull-up; capacitor-to-ground sets ramp (0.65ms/10nF); resistor divider enables tracking - supports coordinated startup with SoC or FPGA power domains. |
| ITH1 (35) | Buck channel 1 error amplifier output | Compensation point for channel 1 loop - connects to RC network for OPTI-LOOP® tuning across wide capacitor/ESR range. |
| VFB1 (36) | Buck channel 1 feedback input | Regulated to 0.8V reference; resistor divider sets output voltage - supports precision regulation from 0.8V to 40V with minimal external components. |
| SENSE1+ (37) | Buck channel 1 current sense positive | Differential input for RSENSE/DCR sensing - used with SENSE1– to set channel 1 current limit independently. |
| SENSE1– (38) | Buck channel 1 current sense negative | Supplies comparator current when > INTVCC; sources majority of sleep-mode IQ when ≥3.2V - enables ultra-low system IQ in standby. |
| PGND (39) | Power ground (exposed pad) | Must be soldered to PCB ground plane - provides low-impedance return path for all gate drivers and high-current paths; critical for thermal and electrical performance. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q100 qualified | Rated for automotive applications (–40°C to 125°C), supporting under-hood and infotainment systems with validated reliability. |
| PassThru™ boost operation | 100% duty cycle for BG3 enables direct VIN-to-VOUT3 conduction during cold crank - maintains regulated output even when input drops to 1V. |
| OPTI-LOOP® compensation | Allows stable loop response across wide output capacitor values (10µF–1000µF) and ESR ranges (0.5mΩ–100mΩ) - eliminates trial-and-error tuning. |
| Independent RUN/SS/ITH per channel | Enables precise power sequencing, staggered startup, and channel-specific transient optimization - critical for complex SoC/FPGA power trees. |
| Triple bias architecture | VBIAS + EXTVCC + SENSE1– bias sourcing reduces total input-referred IQ to 14μA - extends battery life in always-on telematics modules. |
| Programmable light-load modes | Burst Mode, pulse-skipping, or forced continuous selectable per channel - balances efficiency, output ripple, and EMI for each rail's specific load profile. |
Applications
| Automotive Infotainment | ADAS Camera Power Supply |
|---|---|
Use Scenario: Powering head-unit processors, displays, and audio codecs requiring tightly regulated 1.2V, 3.3V, and 5V rails plus 10V camera sensor bias. IC Role / Device Role / Timing Role: Triple-output controller delivering sequenced, low-noise, cold-crank-resilient power with PGOOD monitoring for system safety. Use Value: Eliminates need for discrete controllers and external sequencing ICs; PassThru™ maintains 10V sensor bias during engine cranking (VIN = 1V–12V). |
Use Scenario: Providing isolated, low-EMI 3.3V digital core, 1.8V image sensor, and 10V lens actuator rails in surround-view camera modules. IC Role / Device Role / Timing Role: Synchronous buck/buck/boost controller with independent soft-start and RUN control per channel for safe camera boot sequence. Use Value: 3MHz switching enables small magnetics; OPTI-LOOP® ensures stability with ceramic capacitors; AEC-Q100 grade meets automotive qualification. |
| Industrial PLC I/O Module | EV Onboard Charger Auxiliary Supply |
Use Scenario: Generating 5V logic, 24V field bus, and isolated 15V gate drive rails from 24VDC industrial input with wide temperature operation. IC Role / Device Role / Timing Role: High-voltage triple controller supporting buck (5V), buck (24V), and boost (15V) topologies with robust current sensing. Use Value: 40V input rating handles 24V transients; 14μA IQ minimizes standby power; 38-lead QFN supports high-power density in space-constrained enclosures. |
Use Scenario: Powering MCU, gate drivers, and communication ICs in OBC auxiliary supplies where input varies from 12V (battery) to 400V (HV bus derived). IC Role / Device Role / Timing Role: Controller accepting wide-input auxiliary bias (e.g., from HV DC-DC) to generate 3.3V, 5V, and 12V rails with cold-crank immunity. Use Value: Sub-1V operation after startup enables reliable boot from weak auxiliary sources; EXTVCC switchover optimizes efficiency across input range. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar triple-output synchronous controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC7813EUHF#PBF | Dual buck + single boost, but limited to 2.2MHz max frequency and no PassThru™ boost mode; lacks VPRG3 pin for fixed 8V/10V boost output. | Not qualified for automotive; lower frequency limits magnetics size reduction; missing cold-crank support restricts use in start-stop systems. | Select LTC7817EUHF#PBF when PassThru™, AEC-Q100, or 3MHz operation is required; LTC7813EUHF#PBF suits cost-sensitive industrial designs without cold-crank demands. |
| MP2960AAGQ-P | Triple buck-only controller (no boost); supports up to 2MHz; integrated MOSFET drivers but no EXTVCC switchover or SENSE1– bias current redirection. | Cannot generate boosted rails; lacks cold-crank resilience below 4.5V; not AEC-Q100 qualified; higher typical IQ (25μA) than LTC7817EUHF#PBF. | Choose LTC7817EUHF#PBF for applications needing boost functionality, sub-1V operation, or automotive qualification; MP2960AAGQ-P fits multi-buck-only systems with tighter BOM constraints. |
Compared with LTC7813EUHF#PBF and MP2960AAGQ-P, the LTC7817EUHF#PBF uniquely combines 3MHz operation, PassThru™ boost, AEC-Q100 qualification, and ultra-low 14μA IQ - making it the only option capable of meeting stringent cold-crank and high-density automotive power requirements.
Availability
LTC7817EUHF#PBF is available at Aetrix Electronics and suitable for automotive infotainment, ADAS camera power supplies, and industrial PLC I/O modules requiring stable component supply, long-term lifecycle support, and AEC-Q100-compliant performance.
Supply support for LTC7817EUHF#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 automotive, industrial, communications, and healthcare markets.
The LTC7817EUHF#PBF belongs to Analog Devices' Power by Linear™ controller family, designed specifically for high-efficiency, high-reliability multi-rail power conversion in automotive and industrial environments demanding cold-crank resilience and ultra-low quiescent current.
FAQ
What is the minimum input voltage the LTC7817EUHF#PBF can regulate from after startup?
The LTC7817EUHF#PBF can maintain regulation with input as low as 1V after startup when biased from the boost output or another auxiliary supply. This capability is critical for automotive cold-crank scenarios where battery voltage dips below 5V. The device achieves this using its dual-bias architecture, allowing VBIAS to be powered from a regulated rail rather than directly from the main battery.
How does the LTC7817EUHF#PBF achieve ultra-low 14μA quiescent current?
The LTC7817EUHF#PBF achieves 14μA no-load IQ through three complementary techniques: (1) SENSE1– bias current redirection when ≥3.2V, (2) EXTVCC switchover LDO that bypasses the VBIAS LDO when active, and (3) optimized sleep-mode circuitry that shuts down unused channels. These features collectively minimize input-referred current in battery-powered automotive modules.
What is PassThru™ operation and how does it benefit automotive applications?
PassThru™ operation in the LTC7817EUHF#PBF enables 100% duty cycle for the boost channel's bottom MOSFET (BG3), allowing direct conduction from input to boost output during cold crank. This maintains regulated output (e.g., 10V for camera sensors) even when VIN collapses to 1V - eliminating brownouts and ensuring continuous ADAS functionality during engine start.
Can the LTC7817EUHF#PBF generate fixed 8V or 10V boost outputs without external resistors?
Yes. The LTC7817EUHF#PBF supports fixed 8V or 10V boost outputs via the VPRG3 pin: tying VPRG3 to GND selects 8V, and connecting it to INTVCC selects 10V. In both cases, VFB3 is tied directly to VOUT3, removing the need for external feedback resistors and simplifying design for common automotive boost rails.
What package and thermal characteristics does the LTC7817EUHF#PBF have?
The LTC7817EUHF#PBF uses a 38-lead 5mm × 7mm plastic QFN with an exposed PGND pad (Pin 39). Its thermal resistance is θJA = 34.7°C/W, and it is rated for –40°C to 125°C junction temperature. The exposed pad must be soldered to the PCB ground plane to ensure rated electrical performance and thermal dissipation in high-power automotive and industrial applications.
LTC7817EUHF#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 38-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:
- 3
- Output Phases:
- 2
- Voltage - Supply (Vcc/Vdd):
- 4.5V ~ 40V
- Frequency - Switching:
- 100kHz ~ 3MHz
- Duty Cycle (Max):
- 100%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- Yes
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable, Frequency Control
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 38-QFN (5x7)
LTC7817EUHF#PBF FAQ
1.How can I place an order for LTC7817EUHF#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC7817EUHF#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 LTC7817EUHF#PBF reliable?
The price and inventory of LTC7817EUHF#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC7817EUHF#PBF is usually 5 days.
3.What payment methods are accepted for LTC7817EUHF#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC7817EUHF#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC7817EUHF#PBF?
LTC7817EUHF#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC7817EUHF#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 LTC7817EUHF#PBF?
For technical support, including LTC7817EUHF#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC7817EUHF#PBF requirements.
6.How does Aetrix verify that LTC7817EUHF#PBF is sourced from the original manufacturer or authorized distributors?
All LTC7817EUHF#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 LTC7817EUHF#PBF meets industry standards.
7.What is the process for return or replacement of LTC7817EUHF#PBF?
All LTC7817EUHF#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC7817EUHF#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 LTC7817EUHF#PBF part is unused and in its original packaging.
Return procedure for LTC7817EUHF#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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