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Analog Devices Inc. LT8616HFE#PBF
- Part No.:
- LT8616HFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT8616HFE#PBF.pdf
- Description:
- IC REG BUCK ADJ DL 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,065
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Product details
Overview
LT8616HFE#PBF from Analog Devices (formerly Linear Technology) is a dual-channel synchronous monolithic step-down regulator with 42V input capability, delivering 1.5A on Channel 1 and 2.5A on Channel 2. It operates from 3.4V to 42V input, achieves 6.5µA quiescent current in Burst Mode with both channels active, and supports 180° out-of-phase switching for reduced input ripple - used in automotive infotainment power supplies requiring high reliability at 150°C junction temperature.
For engineers reviewing the LT8616HFE#PBF datasheet, LT8616HFE#PBF pinout, LT8616HFE#PBF application, or LT8616HFE#PBF equivalent, key selection criteria include guaranteed operation up to 150°C junction temperature, independent EN/UV pins for channel control, ultralow IQ regulation at 12VIN→5VOUT/3.3VOUT, and TSSOP-28 package with exposed thermal pad soldered to PCB ground.
Technical Context
The LT8616HFE#PBF integrates two independent peak-current-mode buck regulators sharing internal bias circuitry but featuring separate VIN, EN/UV, PG, TR/SS, FB, and SW paths. Channel 1 supports 1.5A output with 35ns minimum on-time and 310mΩ top-FET RDS(on); Channel 2 delivers 2.5A with 145mΩ top-FET RDS(on) and 5.5A peak current limit. Both channels use internal compensation and support synchronization via SYNC/MODE pin.
Operation includes three modes: low-ripple Burst Mode (SYNC/MODE = GND), pulse-skipping mode (SYNC/MODE ≥ 2.4V), and external clock synchronization (250kHz–3MHz). The device implements independent soft-start/tracking via 2µA current sources on TR/SS pins, ±10% power-good detection on PG outputs, and accurate 1.03V EN rising threshold with 50mV hysteresis per channel.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.4V to 42V - supports wide automotive battery range including cold-crank (4.5V) and load-dump (40V) transients |
| Quiescent Current (Both Channels) | 6.5µA - enables always-on systems like telematics without excessive battery drain |
| Output Current Capability | CH1: 1.5A / CH2: 2.5A - allows independent powering of MCU core (5V) and I/O rail (3.3V) |
| Switching Frequency Range | 200kHz to 3MHz - adjustable via RT resistor; higher frequencies enable smaller magnetics |
| Minimum Switch On-Time | 35ns - supports high VIN/VOUT ratios (e.g., 42V→3.3V at 700kHz) without pulse skipping |
| Junction Temperature Range | –40°C to +150°C - qualified for under-hood automotive applications per AEC-Q100 stress test conditions |
| Package | 28-Lead TSSOP with exposed thermal pad - θJA = 30°C/W; requires PCB thermal relief for reliable 150°C operation |
Pinout & Package
LT8616HFE#PBF is housed in a thermally enhanced 28-lead plastic TSSOP (FE package) with exposed GND pad (Pin 29) that must be soldered to PCB for thermal and electrical integrity. Pin count and layout match LT8616EFE#PBF and LT8616IFE#PBF variants; only temperature grade differs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN1 | Channel 1 input supply | Mandatory ≥3.4V even if only Channel 2 is active; powers internal bias circuits and CH1 top switch |
| VIN2 | Channel 2 input supply | Can be tied to VIN1; no minimum voltage if VIN1 ≥3.4V - enables flexible dual-input configurations |
| EN/UV1, EN/UV2 | Independent enable/undervoltage lockout | 1.03V rising threshold with 50mV hysteresis; allows staged power-up and fault-triggered shutdown per channel |
| FB1, FB2 | Feedback reference inputs | Regulated to 0.790V ±10mV; sets output voltage via resistor divider; phase-lead capacitor (1.5–10pF) required for stability |
| PG1, PG2 | Open-drain power-good indicators | Pull low until respective VOUT is within ±10% of target; used for system sequencing and fault monitoring |
| TR/SS1, TR/SS2 | Soft-start and tracking control | 2µA internal current source charges external capacitor; enables voltage ramping or output tracking (e.g., 3.3V follows 5V) |
| SYNC/MODE | Mode selection and clock sync | GND = Burst Mode; ≥2.4V = pulse-skipping; external clock = synchronized operation with 180° phase shift between channels |
| SW1, SW2 | Power switch node outputs | Connect to inductors and BOOST capacitors; require tight layout to minimize EMI and switching losses |
| BOOST1, BOOST2 | Bootstrap drive supplies | 0.1µF ceramic caps placed between BOOSTx and SWx; critical for top-FET gate drive above VIN |
| RT | Frequency programming | Resistor to GND sets fSW from 200kHz–3MHz; formula: RT(kΩ) = 0.6/fSW² + 42.6/fSW – 6.1 |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent buck regulators | Enables simultaneous generation of 5V/1.5A and 3.3V/2.5A from single 12V–42V input without cross-regulation issues |
| 180° out-of-phase switching | Reduces RMS input capacitor ripple current by ~30% versus in-phase operation - extends capacitor life in automotive environments |
| Ultralow 6.5µA quiescent current | Supports >1-year battery standby in always-on vehicle modules (e.g., remote keyless entry receivers) without recharge |
| Internal compensation | Eliminates need for external compensation network - reduces BOM count and design iteration time for standard inductor/capacitor selections |
| Thermally enhanced TSSOP-28 | Exposed GND pad lowers θJA to 30°C/W - sustains full 2.5A output at 150°C junction temperature with minimal PCB copper area |
| Accurate 1V enable thresholds | Allows precise undervoltage lockout programming using resistor dividers - prevents brownout operation during battery sag |
Applications
| Automotive Infotainment Power Supply | Industrial PLC I/O Module |
|---|---|
Use Scenario: Powering head unit SoC (5V core) and USB/HDMI interface rails (3.3V) from 12V vehicle battery with load dump immunity. IC Role / Device Role / Timing Role: Dual-output DC/DC controller providing regulated, sequenced, and monitored power with PG signaling for safe boot. Use Value: 42V absolute max rating withstands ISO 7637-2 Pulse 5a (load dump); 150°C rating ensures operation near engine bay heat sources. | Use Scenario: Generating isolated 5V logic and 3.3V sensor interface voltages in DIN-rail mounted programmable logic controllers. IC Role / Device Role / Timing Role: Primary non-isolated DC/DC stage converting 24V industrial bus to dual regulated outputs with independent enable control. Use Value: Independent EN/UV pins allow firmware-controlled power cycling of I/O banks; 6.5µA IQ extends backup battery runtime during AC loss. |
| Telematics Control Unit (TCU) | Railway Signaling Interface |
Use Scenario: Powering LTE modem (3.3V/1.2A), GNSS receiver (3.3V/0.3A), and microcontroller (5V/0.5A) in always-connected vehicle gateway. IC Role / Device Role / Timing Role: Always-on primary regulator with Burst Mode enabling <10µA system sleep current. Use Value: 35ns min on-time supports 42V→3.3V conversion at 1MHz - reduces inductor size by 40% vs 500kHz designs. | Use Scenario: Converting 72V/110V railway traction battery to 5V control logic and 3.3V communication interface in wayside signaling equipment. IC Role / Device Role / Timing Role: High-input-voltage dual buck converter with robust UVLO and thermal shutdown for safety-critical infrastructure. Use Value: Guaranteed 150°C operation meets EN 5012X ambient requirements; PG outputs feed watchdog circuitry for SIL-2 compliance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-output buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3375EFE#PBF | 8-channel configurable buck (1–4 outputs), lower max input (20V), 2.5µA IQ, QFN-48 | Targets multi-rail low-voltage systems (e.g., FPGA cores); lacks 42V rating and automotive temp grade | Select when >2 outputs or sub-20V input is required; not suitable for 42V automotive or railway applications |
| MPQ4436AGL-AEC1-P | Single 3.5A buck, 3.8–60V input, 17µA IQ, AEC-Q100 Grade 1 (–40°C to 125°C), QFN-13 | Single-output only; higher IQ; lower max junction temperature than LT8616HFE#PBF | Use for cost-sensitive single-rail designs where dual output is unnecessary; cannot replace LT8616HFE#PBF in dual-rail systems |
Compared with LTC3375EFE#PBF and MPQ4436AGL-AEC1-P, the LT8616HFE#PBF uniquely combines 42V input, dual independent 1.5A/2.5A outputs, 6.5µA IQ, and 150°C operation - making it the only option qualified for high-reliability dual-rail automotive and railway power conversion.
Availability
LT8616HFE#PBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial PLCs, telematics control units, and railway signaling interfaces requiring stable component supply across extended temperature and long product lifecycles.
Supply support for LT8616HFE#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 acquired Linear Technology in 2017 and maintains full product support, documentation, and manufacturing continuity for the LT® series.
The LT8616HFE#PBF belongs to the LT86xx family of high-efficiency, high-input-voltage synchronous buck regulators designed specifically for automotive, industrial, and transportation applications demanding ultralow quiescent current and extended temperature operation.
FAQ
What is the maximum junction temperature specification for the LT8616HFE#PBF?
The LT8616HFE#PBF is guaranteed to operate over a junction temperature range of –40°C to +150°C. This H-grade qualification makes it suitable for under-hood automotive applications and high-ambient industrial environments where standard E- or I-grade variants (–40°C to +125°C) would fail thermal derating constraints. The LT8616HFE#PBF achieves this via enhanced process and packaging validation per AEC-Q100 stress test conditions.
How does the LT8616HFE#PBF achieve 6.5µA quiescent current with both channels enabled?
The LT8616HFE#PBF achieves 6.5µA total input quiescent current in Burst Mode by shutting down all switching and control circuitry between energy pulses, leaving only essential bias circuits active. Each channel contributes ~3µA base current plus feedback divider current reflected to VIN. With optimized 1MΩ/316kΩ dividers (2.5µA per channel), the LT8616HFE#PBF reaches 6.5µA total - verified at 12VIN → 5VOUT/3.3VOUT with no load. This is measured with SYNC/MODE grounded.
Can the LT8616HFE#PBF synchronize both channels to an external clock?
Yes, the LT8616HFE#PBF supports external clock synchronization via the SYNC/MODE pin. When driven with a clean CMOS clock signal (250kHz–3MHz), Channel 1 aligns its positive switching edge to the external clock's rising edge, while Channel 2 aligns to the falling edge - maintaining inherent 180° phase separation. This reduces EMI peaks and input ripple without requiring additional timing components. The LT8616HFE#PBF does not require matching clock duty cycle or amplitude beyond standard logic thresholds.
What is the purpose of the BIAS pin on the LT8616HFE#PBF?
The BIAS pin on the LT8616HFE#PBF supplies the internal gate drivers and control circuits when connected to a voltage ≥3.1V - typically tied to the highest output voltage (e.g., VOUT1 = 5V). Doing so reduces input current drawn from VIN1, improving light-load efficiency. If unused, the BIAS pin must be grounded. A 1µF ceramic capacitor is required between BIAS and GND if connected to a supply other than VOUT1 or VOUT2. The LT8616HFE#PBF draws 7mA from BIAS under full load (1A per channel).
Does the LT8616HFE#PBF support output voltage tracking during startup?
Yes, the LT8616HFE#PBF supports output voltage tracking via the TR/SS1 and TR/SS2 pins. By connecting a resistor divider from one output (e.g., 5V) to TR/SS2, Channel 2's output will ramp proportionally to Channel 1's output during startup - preventing back-powering or latch-up in downstream logic. Internal 2µA current sources charge external soft-start capacitors, and regulation follows the TR/SS voltage until it exceeds 0.790V, at which point the internal reference resumes control. This function is fully independent per channel in the LT8616HFE#PBF.
LT8616HFE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 2
- Voltage - Input (Min):
- 3.4V
- Voltage - Input (Max):
- 42V
- Voltage - Output (Min/Fixed):
- 0.79V
- Voltage - Output (Max):
- 41.8V
- Current - Output:
- 1.5A, 2.5A
- Frequency - Switching:
- 200kHz ~ 3MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSSOP-EP
LT8616HFE#PBF FAQ
1.How can I place an order for LT8616HFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8616HFE#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 LT8616HFE#PBF reliable?
The price and inventory of LT8616HFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8616HFE#PBF is usually 5 days.
3.What payment methods are accepted for LT8616HFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8616HFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8616HFE#PBF?
LT8616HFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8616HFE#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 LT8616HFE#PBF?
For technical support, including LT8616HFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8616HFE#PBF requirements.
6.How does Aetrix verify that LT8616HFE#PBF is sourced from the original manufacturer or authorized distributors?
All LT8616HFE#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 LT8616HFE#PBF meets industry standards.
7.What is the process for return or replacement of LT8616HFE#PBF?
All LT8616HFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8616HFE#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 LT8616HFE#PBF part is unused and in its original packaging.
Return procedure for LT8616HFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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