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Analog Devices Inc. LT8603JUJ#TRPBF
- Part No.:
- LT8603JUJ#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 40-WFQFN Exposed Pad
- Datasheet:
-
LT8603JUJ#TRPBF.pdf
- Description:
- 42V, L IQ, 4X OUT 3X MONO BUCK C
- Quantity:
- Payment:
- Shipping:
Inventory:2,329
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Product details
Overview
LT8603JUJ#TRPBF from Analog Devices is a quad-output automotive-grade power management IC integrating two 42V synchronous buck regulators (1.5A and 2.5A), one 5.5V low-voltage buck regulator (1.8A), and a boost controller for cold-crank resilient supply generation. It delivers precise regulation across –40°C to 150°C junction temperature, supports 250kHz–2.2MHz switching, and enables four regulated outputs in compact 6mm × 6mm QFN.
For engineers reviewing the LT8603JUJ#TRPBF datasheet, LT8603JUJ#TRPBF pinout, LT8603JUJ#TRPBF application, or LT8603JUJ#TRPBF equivalent, key selection considerations include cold-crank tolerance (VBATT down to 2V), AEC-Q100 qualification, channel-specific enable sequencing, programmable POR delay via CPOR capacitor, and boost controller current-sense interface for external MOSFET control.
Technical Context
The LT8603JUJ#TRPBF implements independent oscillator control per channel group: Channels 1/2 share a programmable RT-based oscillator (250kHz–2.2MHz), Channel 3 uses fixed-frequency operation with soft-start, and Channel 4's boost controller operates at selectable frequencies via FSEL4A/FSEL4B logic inputs. All buck channels feature cycle-by-cycle current limiting, thermal shutdown, and ±42V reverse-battery tolerant ISP4/ISN4 inputs.
Its architecture supports two primary configurations: (1) boost controller supplies VIN to high-voltage bucks during cold crank (VBATT < VOUT), enabling triple output regulation below 2V input; or (2) boost configured as SEPIC or driven from a buck output to deliver four independent regulated rails. Power-good indicators (PG1–PG4) provide individual channel status with 8% hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | Channels 1/2: 3V–42V; Channel 3: 2.6V–5.5V; Boost sense: –42V to 42V common-mode |
| Output Current Capability | Channel 1: 1.5A; Channel 2: 2.5A; Channel 3: 1.8A; Boost controller drives external MOSFETs |
| Feedback Reference Voltage | Channels 1/2: 1.000V ±1.5%; Channels 3/4: 0.800V ±1.5% - sets regulation accuracy and PG thresholds |
| Quiescent Current | 28µA typical with high-voltage channels active in Burst Mode® - enables always-on automotive systems |
| Switching Frequency Range | 250kHz–2.2MHz (RT-programmable for Ch1/2); 250kHz–2.2MHz (FSEL-selectable for Ch4) - allows EMI optimization and size trade-offs |
| Operating Temperature | –40°C to +150°C junction - qualified per AEC-Q100 Grade 1, suitable for under-hood automotive placement |
| Power Good Thresholds | Lower: 92% of VFB; Upper: 107% of VFB; Hysteresis: 0.8% - ensures reliable rail monitoring in noisy environments |
Pinout & Package
LT8603JUJ#TRPBF is housed in a thermally enhanced 40-lead (6mm × 6mm) plastic QFN package with exposed thermal pad (Pin 41). All ground pins (Pins 2, 8, 13, 35, 38) and the exposed pad must be soldered to PCB ground for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PG1 (Pin 1) | Open-drain power-good indicator | Pulls low until FB1 reaches 92%–107% of 1.000V reference - signals stable 5V rail |
| SW1 (Pin 3) | High-side switch node | Connects to external inductor and output capacitor for Channel 1 buck - requires low-inductance layout |
| BST1/BST2 (Pins 4,5) | Bootstrap voltage supply | Drives high-side MOSFET gates; requires ceramic capacitor from BSTx to SWx |
| FB1/FB2 (Pins 26,25) | Voltage feedback input | Sets regulated output via resistor divider; reference = 1.000V ±1.5% - determines accuracy and load regulation |
| ISP4/ISN4 (Pins 19,18) | Boost current-sense differential inputs | Monitor external MOSFET current; threshold = 41–57mV (J-grade) - enables overcurrent protection |
| POREN (Pin 39) | Power-on reset enable input | Active-high logic input that initiates CPOR timing capacitor ramp - controls system boot sequence |
| RST (Pin 32) | Active-low reset output | Open-drain output held low until POR timeout (31–39ms with 1nF CPOR) - resets downstream logic |
Key Features
| Feature | Design Value |
|---|---|
| Cold-crank resilient triple output | Regulates three outputs even when VBATT drops to 2V - enables uninterrupted CPU/memory power during automotive start-stop |
| Selectable Burst Mode® operation | Reduces no-load IQ to 28µA while maintaining regulation - extends battery life in always-on modules |
| Programmable power-on reset | CPOR capacitor sets POR delay from 31ms to 39ms - ensures deterministic system initialization timing |
| Individual channel power-good indicators | Four open-drain PG outputs (PG1–PG4) with 8% hysteresis - enables per-rail fault detection and sequencing |
| AEC-Q100 Grade 1 qualification | Validated for –40°C to +150°C operation - meets automotive reliability and lifetime requirements |
Applications
| Automotive Stop-Start Systems | Last-Gasp CPU Hold-Up |
|---|---|
Use Scenario: Vehicle engine restarts after brief stop; battery voltage collapses to 2.5V for 100ms. IC Role / Device Role / Timing Role: LT8603JUJ#TRPBF boost controller maintains VIN above dropout for high-voltage bucks, delivering stable 5V/3.3V/1.2V rails. Use Value: Prevents microcontroller brownout and memory corruption during transient low-VBATT events. | Use Scenario: Ignition turned off; vehicle battery slowly discharges while critical ECUs retain volatile state. IC Role / Device Role / Timing Role: LT8603JUJ#TRPBF low-quiescent-current operation sustains 3.3V rail for RAM backup and real-time clock. Use Value: Enables >10-second hold-up time using small 100µF output capacitance at 28µA IQ. |
| Industrial Control Power Supply | Automotive Infotainment Core Supply |
Use Scenario: Programmable logic controller requiring isolated 5V, 3.3V, and 1.2V rails from unregulated 24V DC bus. IC Role / Device Role / Timing Role: LT8603JUJ#TRPBF integrates all three buck regulators plus boost for auxiliary 12V rail - eliminates discrete controllers. Use Value: Reduces BOM count by 4 ICs and saves >120mm² PCB area versus discrete solution. | Use Scenario: Head unit SoC requiring tightly sequenced 1.0V core, 1.8V I/O, and 3.3V peripheral rails during cold ambient startup. IC Role / Device Role / Timing Role: LT8603JUJ#TRPBF TRKSS1/TRKSS2 pins enable controlled soft-start ramping; RUN3 sequences Channel 3 after main rails stabilize. Use Value: Eliminates external sequencing IC and prevents SoC latch-up during temperature-dependent startup. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad-output automotive power management applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8602JUJ#TRPBF | Dual-output version (two 42V bucks only); no boost controller or low-voltage buck; smaller 32-lead QFN | Lacks fourth rail generation capability; cannot support cold-crank triple-output or SEPIC topologies | Select when only dual high-voltage rails needed and board space is constrained |
| MAX20090ATPA/VY+ | Triple-output (2×42V buck + 1×5.5V buck); no integrated boost controller; requires external boost for cold-crank | Needs external boost circuitry to achieve sub-4V operation; higher component count and layout complexity | Select when boost functionality is implemented separately and lower channel count suffices |
Compared with LT8602JUJ#TRPBF and MAX20090ATPA/VY+, the LT8603JUJ#TRPBF uniquely integrates all four regulation functions-including cold-crank-tolerant boost-in a single AEC-Q100-qualified package, reducing design risk and validation effort for complex automotive power trees.
Availability
LT8603JUJ#TRPBF is available at Aetrix Electronics and suitable for automotive stop-start systems, industrial control power supplies, infotainment head units, and last-gasp CPU hold-up circuits requiring stable component supply across extended temperature ranges.
Supply support for LT8603JUJ#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving automotive, industrial, communications, and healthcare markets.
The LT8603 product line delivers highly integrated, AEC-Q100-qualified power management solutions targeting automotive subsystems requiring cold-crank resilience, ultra-low quiescent current, and multi-rail sequencing - such as ADAS domain controllers and body electronics modules.
FAQ
What is the maximum junction temperature rating for the LT8603JUJ#TRPBF?
The LT8603JUJ#TRPBF is guaranteed over the full –40°C to +150°C junction temperature range and qualified per AEC-Q100 Grade 1. This rating enables direct placement in high-temperature under-hood locations without derating, unlike E- or I-grade variants limited to 125°C.
How does the LT8603JUJ#TRPBF support automotive cold-crank conditions?
The LT8603JUJ#TRPBF supports cold-crank by configuring its boost controller to supply VIN to the high-voltage buck regulators. When VBATT drops to 2V, the boost maintains sufficient input voltage to sustain regulation on all three buck outputs - verified in Figure TA01b of the datasheet showing stable 5V/3.3V/1.2V during 2V–8.5V input transients.
Can the LT8603JUJ#TRPBF generate four independent regulated outputs simultaneously?
Yes. The LT8603JUJ#TRPBF can deliver four regulated outputs: three from its integrated buck regulators (Ch1: 5V/1.5A, Ch2: 3.3V/2.5A, Ch3: 1.2V/1.8A) and one from its external-MOSFET boost controller (e.g., 8V/2A). Configuration as SEPIC or driving the boost from a buck output enables full four-rail operation across wide input ranges.
What is the purpose of the TRKSS1 and TRKSS2 pins on the LT8603JUJ#TRPBF?
The TRKSS1 and TRKSS2 pins on the LT8603JUJ#TRPBF provide track/soft-start control for Channels 1 and 2. When pulled below 1V, they override the internal 1.000V reference and force regulation to the TRKSS voltage instead - enabling precise output sequencing and controlled ramp-up. A capacitor to ground programs soft-start time (~1ms typical).
How is power-good signaling implemented on the LT8603JUJ#TRPBF?
The LT8603JUJ#TRPBF provides four open-drain power-good outputs (PG1–PG4), each tied to its respective channel's feedback pin. Each PG pin pulls low until its FB voltage reaches 92% of reference (lower threshold) and releases when it exceeds 107% (upper threshold), providing 0.8% hysteresis to reject noise-induced false triggers during regulation.
LT8603JUJ#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 40-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Up/Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck-Boost
- Number of Outputs:
- 4
- Output Phases:
- 2
- Voltage - Supply (Vcc/Vdd):
- 3V ~ 42V
- Frequency - Switching:
- 250kHz ~ 2.2MHz
- Duty Cycle (Max):
- -
- Synchronous Rectifier:
- Yes
- Clock Sync:
- Yes
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Power Good, Soft Start
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 40-QFN (6x6)
LT8603JUJ#TRPBF FAQ
1.How can I place an order for LT8603JUJ#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8603JUJ#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 LT8603JUJ#TRPBF reliable?
The price and inventory of LT8603JUJ#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8603JUJ#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8603JUJ#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8603JUJ#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8603JUJ#TRPBF?
LT8603JUJ#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8603JUJ#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 LT8603JUJ#TRPBF?
For technical support, including LT8603JUJ#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8603JUJ#TRPBF requirements.
6.How does Aetrix verify that LT8603JUJ#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8603JUJ#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 LT8603JUJ#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8603JUJ#TRPBF?
All LT8603JUJ#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8603JUJ#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 LT8603JUJ#TRPBF part is unused and in its original packaging.
Return procedure for LT8603JUJ#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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