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Analog Devices Inc. LT3690MPUFE#TRPBF
- Part No.:
- LT3690MPUFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 26-WFQFN Exposed Pad
- Datasheet:
-
LT3690MPUFE#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 4A 26QFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,864
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Product details
Overview
LT3690MPUFE#TRPBF from Analog Devices is a 36V, 4A, 1.5MHz synchronous step-down switching regulator with 70µA quiescent current in Burst Mode, integrated 30mΩ N-channel low-side switch, and programmable undervoltage lockout. It operates from 3.9V to 36V input, delivers 0.8V–20V adjustable output, and features power good flag, soft-start, and thermal shutdown - used in automotive power supplies requiring high transient immunity and wide temperature operation.
For engineers reviewing the LT3690MPUFE#TRPBF datasheet, LT3690MPUFE#TRPBF pinout, LT3690MPUFE#TRPBF application, or LT3690MPUFE#TRPBF equivalent, key selection criteria include its –55°C to 150°C extended temperature grade, 26-lead 4mm × 6mm QFN package with exposed SW/GND pads, 1.5MHz max switching frequency, 0.8V feedback reference, and robust short-circuit protection with frequency foldback.
Technical Context
The LT3690MPUFE#TRPBF employs current-mode control for fast transient response and stable loop behavior across wide duty cycles. Its internal architecture integrates a bipolar NPN high-side switch and synchronous N-channel MOSFET low-side switch, driven by a boost-regulated BST circuit and internally generated VCCINT supply.
It supports programmable oscillator (170kHz–1.5MHz) via RT resistor, offers soft-start/tracking via SS pin with 2µA pull-up, and implements low-ripple Burst Mode operation below ~100mA load while maintaining <15mVP-P output ripple. Protection includes overvoltage lockout (38.2V typ), thermal shutdown, and cycle-by-cycle current limiting with hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.9V to 36V continuous; withstands 60V non-repetitive transients - enables robust operation in automotive battery systems with load dump. |
| Output Current | Up to 4A DC - sufficient for powering microcontrollers, FPGAs, and sensor subsystems without external current boosting. |
| Quiescent Current | 70µA at 12VIN→3.3VOUT in Burst Mode - extends battery life in always-on vehicle modules. |
| Feedback Reference | 0.8V ±12mV over temperature - allows precise output regulation with standard resistor dividers and minimizes sensing error. |
| Switching Frequency | Programmable 170kHz–1.5MHz via RT pin - balances inductor size, efficiency, and EMI in space-constrained designs. |
| Low-Side RDS(on) | 30mΩ (typ) at VCCINT = 5V - eliminates need for external Schottky diode and improves full-load efficiency by ~3–5%. |
| Operating Temperature | –55°C to +150°C junction - qualified for under-hood automotive applications per AEC-Q100 stress test requirements. |
Pinout & Package
The LT3690MPUFE#TRPBF is housed in a thermally enhanced 26-lead 4mm × 6mm plastic QFN package with two exposed pads: Pin 27 (SW) and Pin 28 (GND), both requiring solder connection to PCB copper for optimal thermal performance (θJA = 40°C/W, θJC = 2.7°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (Pins 1–4, 23–26, Exposed Pad 27) | Switch node | Drain of LS MOSFET and emitter of HS NPN; connects to inductor and BST capacitor; must be routed with low-inductance path. |
| FB (Pin 9) | Feedback input | Regulates output by servoing to 0.8V reference; connects to resistor divider tap - accuracy directly impacts output voltage tolerance. |
| RT (Pin 7) | Oscillator programming | Sets switching frequency via resistor to GND; 10kΩ yields 1.5MHz, 32.4kΩ yields 600kHz - determines inductor/capacitor sizing trade-offs. |
| PG (Pin 18) | Power good flag | Open-collector output asserting when VOUT reaches 90% of target - used for system sequencing and fault detection. |
| EN (Pin 17) | Enable control | Active-high logic input; >1.5V enables regulation, <0.4V forces shutdown (<1µA IQ) - enables system-level power management. |
| UVLO (Pin 12) | Undervoltage lockout | Accepts resistor divider from VIN; internal 1.25V threshold - allows custom startup voltage (e.g., 6V min) to prevent brownout operation. |
| BST (Pin 22) | Bootstrap supply | Drives HS NPN base via external capacitor; requires ≥10nF ceramic cap between BST and SW - critical for full saturation and low conduction loss. |
| VCCINT (Pin 20) | LS gate driver supply | Internally regulated ~5V output; powers LS MOSFET driver - requires 1µF ceramic bypass to GND (Pin 21) for stability. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated synchronous power stage | Eliminates external catch diode and reduces board area by >30% vs. asynchronous buck controllers. |
| Burst Mode® operation | Maintains <15mVP-P output ripple at light loads while achieving 70µA IQ - essential for always-on telematics modules. |
| Programmable UVLO with hysteresis | Enables reliable cold-crank start in automotive systems by setting custom turn-on/turn-off thresholds (e.g., 6.2V/5.8V). |
| Robust overvoltage protection | Disables switching above 38.2V (typ), sustaining 60V transients - meets ISO 7637-2 Pulse 5a requirements without external clamping. |
| Thermal shutdown with hysteresis | Activates at TJ ≥ 150°C (MP grade), latches off until cooldown - prevents thermal runaway in sealed enclosures. |
Applications
| Automotive Infotainment Power Supply | Industrial PLC I/O Module |
|---|---|
Use Scenario: Powers SoC, display interface, and audio codec in head-unit with 12V battery input subject to load dump and cold-crank conditions. IC Role / Device Role / Timing Role: Primary DC/DC converter delivering 3.3V/2A and 5V/2A rails with independent PG signaling. Use Value: –55°C to 150°C rating ensures reliability under hood; 60V transient tolerance avoids need for TVS diodes on input. | Use Scenario: Supplies isolated ADCs, digital I/O drivers, and fieldbus transceivers in DIN-rail mounted controller with 24V industrial bus. IC Role / Device Role / Timing Role: Point-of-load regulator converting 24V to 5V for analog front-end and 3.3V for microcontroller core. Use Value: 4A capability supports burst-current demands of solenoid drivers; programmable frequency avoids noise coupling into sensitive analog circuits. |
| Ruggedized Telematics Gateway | Avionics Sensor Conditioning Unit |
Use Scenario: Powers LTE modem, GNSS receiver, and CAN transceiver in vehicle-to-cloud gateway operating continuously in parked mode. IC Role / Device Role / Timing Role: Always-on buck regulator with ultra-low IQ and soft-start to prevent inrush during wake-up events. Use Value: 70µA Burst Mode current extends backup battery life to >30 days; SS pin enables seamless voltage tracking during sleep/wake transitions. | Use Scenario: Provides stable 3.3V and 5V rails for MEMS accelerometers, pressure sensors, and signal conditioning op-amps in flight control electronics. IC Role / Device Role / Timing Role: High-reliability power source meeting DO-160 Section 22 lightning-induced transient requirements. Use Value: Dual overvoltage/undervoltage lockout plus thermal shutdown satisfies safety-critical fault containment requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5164QPWPRQ1 | 42V input, 0.5A output, 100kHz–2.2MHz sync-capable; no integrated low-side FET - requires external MOSFET. | Lower current capacity; suited for auxiliary rails, not main SoC supply. | Select when lower cost and smaller footprint outweigh need for 4A output and integrated LS switch. |
| TPS544B20RHLT | 18V input, 4A output, 500kHz–2MHz; integrated FETs but only rated to 125°C junction. | Lacks automotive-grade temp range and 60V transient tolerance. | Prefer for commercial/industrial applications where extended temperature and transient immunity are not required. |
Compared with LM5164QPWPRQ1 and TPS544B20RHLT, the LT3690MPUFE#TRPBF uniquely combines 4A output, –55°C to 150°C operation, 60V transient survival, and fully integrated synchronous power stage - making it the only drop-in solution for high-reliability automotive main rail conversion.
Availability
LT3690MPUFE#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial PLCs, ruggedized telematics gateways, and avionics sensor conditioning units requiring stable component supply across extended temperature and high-transient environments.
Supply support for LT3690MPUFE#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 precision instrumentation, industrial automation, and automotive markets since 1965.
The LT3690MPUFE#TRPBF belongs to Analog Devices' Power by Linear™ family of monolithic DC/DC regulators, engineered specifically for demanding automotive and industrial applications requiring wide input range, high reliability, and extended temperature operation.
FAQ
What is the maximum continuous input voltage rating for the LT3690MPUFE#TRPBF?
The LT3690MPUFE#TRPBF has a maximum continuous input voltage rating of 36V. It can withstand non-repetitive 60V transients for up to 1 second when junction temperature remains below 125°C. During transients exceeding 38.2V (typical OVLO threshold), the device disables switching to protect internal circuitry while maintaining safe bias conditions - a key feature for automotive load-dump immunity.
Does the LT3690MPUFE#TRPBF require an external Schottky diode?
No, the LT3690MPUFE#TRPBF does not require an external Schottky diode. It integrates a synchronous 30mΩ N-channel MOSFET low-side switch that replaces the catch diode, improving full-load efficiency by eliminating forward voltage drop and reducing thermal dissipation. This integration simplifies layout and reduces bill-of-materials cost compared to asynchronous buck regulators.
How is the switching frequency programmed on the LT3690MPUFE#TRPBF?
The switching frequency of the LT3690MPUFE#TRPBF is programmed using a single resistor (RT) connected from Pin 7 (RT) to ground. The value determines frequency across 170kHz–1.5MHz: e.g., 10.0kΩ sets 1.5MHz, 32.4kΩ sets 600kHz, and 180kΩ sets 138kHz. This resistor-based configuration avoids timing capacitor drift and provides precise, stable frequency control across temperature and voltage.
What is the purpose of the exposed pad labeled "SW" on the LT3690MPUFE#TRPBF package?
Pin 27 (exposed pad) on the LT3690MPUFE#TRPBF is electrically connected to the internal switch node (SW) and must be soldered to a large PCB copper area. This pad serves dual purposes: (1) it provides the primary thermal path for dissipating up to 3W of power, lowering junction temperature rise by >40°C versus standard pad routing; and (2) it minimizes high-frequency switching loop inductance, reducing EMI and voltage spikes at the SW node.
Can the LT3690MPUFE#TRPBF operate in Burst Mode and still provide a valid power good signal?
Yes, the LT3690MPUFE#TRPBF maintains a valid power good (PG) signal during Burst Mode operation. The PG pin asserts high (via external pull-up) when the FB pin reaches 90% of the regulated output voltage, regardless of operating mode. This behavior is guaranteed down to light loads and remains active during Burst Mode cycles - enabling reliable system sequencing and fault monitoring even in ultra-low-power states.
LT3690MPUFE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 26-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3.9V
- Voltage - Input (Max):
- 36V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 20V
- Current - Output:
- 4A
- Frequency - Switching:
- 138kHz ~ 1.5MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 26-QFN (4x6)
LT3690MPUFE#TRPBF FAQ
1.How can I place an order for LT3690MPUFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3690MPUFE#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 LT3690MPUFE#TRPBF reliable?
The price and inventory of LT3690MPUFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3690MPUFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3690MPUFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3690MPUFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3690MPUFE#TRPBF?
LT3690MPUFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3690MPUFE#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 LT3690MPUFE#TRPBF?
For technical support, including LT3690MPUFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3690MPUFE#TRPBF requirements.
6.How does Aetrix verify that LT3690MPUFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3690MPUFE#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 LT3690MPUFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3690MPUFE#TRPBF?
All LT3690MPUFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3690MPUFE#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 LT3690MPUFE#TRPBF part is unused and in its original packaging.
Return procedure for LT3690MPUFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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