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Analog Devices Inc. LT3668IMSE#TRPBF
- Part No.:
- LT3668IMSE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Voltage Regulators - Linear + Switching
- Package:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3668IMSE#TRPBF.pdf
- Description:
- IC REG TRIPLE BUCK/LINEAR 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,650
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Product details
Overview
LT3668IMSE#TRPBF from Analog Devices (formerly Linear Technology) is a monolithic triple-output power management IC integrating a 400mA buck switching regulator and two 200mA fault-protected linear tracking LDOs. It delivers tightly regulated 6V/5V outputs with ±45V fault protection, 50µA no-load quiescent current, and operates from 4.3V to 40V input - ideal for sensor-ASIC power supply tracking in automotive and industrial instrumentation.
For engineers reviewing the LT3668IMSE#TRPBF datasheet, LT3668IMSE#TRPBF pinout, LT3668IMSE#TRPBF application, or LT3668IMSE#TRPBF equivalent, key selection considerations include its dual programmable-current-limit LDOs, 16-lead MSOP thermal package, ±45V fault tolerance on ADJ/OUT/IN pins, and integrated power-good indicator with ±10% FB1 regulation window.
Technical Context
The LT3668IMSE#TRPBF implements current-mode control for the buck stage (250kHz–2.2MHz programmable via RT pin), enabling fast transient response and stable loop behavior with ceramic output capacitors. Its dual LDOs use precision error amplifiers to track external reference voltages applied at ADJ2/ADJ3 pins with ≤15mV tracking error over temperature and load.
Burst Mode® operation maintains <15mVP-P output ripple at light loads while achieving 50µA total no-load supply current. Internal protection includes reverse-battery protection, thermal shutdown, current limiting with foldback, and ±45V absolute maximum ratings on all LDO-related terminals (ADJ2/3, OUT2/3, IN2, IN3/BD).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.3V to 40V continuous; withstands 60V transients - enables direct connection to 12V/24V/36V automotive and industrial rails. |
| Buck Output Current | 400mA with internal NPN switch - eliminates need for external MOSFET or driver in compact power designs. |
| LDO Output Current | 200mA per LDO (OUT2/OUT3) - sufficient for powering analog front-ends, ADCs, or low-power microcontrollers. |
| Quiescent Current | 50µA at 12VIN with 6V/5V outputs unloaded - critical for battery-backed or always-on sensor systems. |
| Tracking Error | ±6mV (1.1–5V ADJ range, –40°C to 125°C) - ensures sensor supply voltage tracks ASIC supply within tight analog measurement tolerances. |
| Fault Protection | ±45V rating on ADJ2/3, OUT2/3, IN2, IN3/BD - protects against load dump, reverse battery, and ESD events without external clamps. |
| Package | 16-lead MSOP with exposed pad - provides θJA = 40°C/W thermal resistance for high-power-density layouts. |
Pinout & Package
The LT3668IMSE#TRPBF is housed in a thermally enhanced 16-lead MSOP package (MSE) with exposed pad (Pin 17) that must be soldered to PCB ground for optimal thermal performance and electrical stability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (1) | Switch node | Connects to inductor, catch diode anode (DA), and boost capacitor - carries high-frequency pulsed current; requires low-inductance layout. |
| BOOST (2) | Boost drive | Supplies >VIN voltage to internal NPN switch base via 0.22µF capacitor - enables full saturation and low VCE(SAT) (~300mV). |
| EN (3) | Enable control | Logic-level shutdown input (0.3V/1.1V threshold); pulls total supply current <1µA when grounded. |
| RT (4) | Oscillator frequency set | Resistor-to-ground sets switching frequency from 250kHz to 2.2MHz - trade-off between efficiency, size, and dropout. |
| IN3/BD (5) | LDO3 input / boost diode anode | Accepts 1.6–30V input; also supplies bias current to internal regulator when >3.2V - improves system efficiency. |
| OUT3 (6) | LDO3 output | 200mA regulated output tracking ADJ3 voltage; requires ≥10µF ceramic capacitor for stability. |
| ADJ3 (9) | LDO3 reference input | Voltage setpoint for OUT3; tracking error ±6mV over –40°C to 125°C - enables precise sensor supply matching. |
| FB1 (8) | Buck feedback | Regulated to 1.200V ±12mV; used with resistor divider to set buck output (e.g., 6V or 5V). |
| IN2 (11) | LDO2 input | 1.6–45V input for second LDO; supports independent sourcing from buck output or separate rail. |
| OUT2 (10) | LDO2 output | 200mA regulated output tracking ADJ2 voltage; identical specs and capacitor requirement as OUT3. |
| EN2/ILIM2 (12) | LDO2 enable / current limit | Resistor-to-GND sets current limit (e.g., 10mA–197mA); >1.2V disables LDO2 - integrates enable and protection. |
| EN3/ILIM3 (13) | LDO3 enable / current limit | Functionally identical to EN2/ILIM2 - allows independent programming of each LDO's current limit and shutdown. |
| PG (14) | Power good indicator | Open-drain output active-low until FB1 is within ±10% of 1.2V - signals valid buck regulation to host controller. |
| IN1 (15) | Buck input | Main input for buck regulator (4.3–40V); powers internal switch, oscillator, and control logic. |
| DA (16) | Catch diode anode sense | Connects to external Schottky diode anode; senses diode current for frequency foldback during overload. |
| GND (17) | Power & signal ground | Exposed pad must be soldered to PCB ground plane - essential for thermal dissipation and noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| Dual programmable-current-limit LDOs | Each LDO supports resistor-programmed current limit (9.5–230mA) with ±5% accuracy - replaces discrete current-limit circuits and enables per-rail fault management. |
| Fault-protected tracking architecture | ±45V absolute max on ADJ/OUT/IN pins and ±45V differential ratings - eliminates need for external TVS diodes in harsh environments. |
| Low-noise Burst Mode® operation | Maintains <15mVP-P output ripple at light loads while drawing only 50µA - preserves signal integrity in precision analog systems. |
| Thermally optimized MSOP package | 16-lead MSOP with exposed pad achieves θJA = 40°C/W - enables 400mA buck + dual 200mA LDOs in <25mm² footprint. |
| Integrated power-good monitoring | PG pin asserts open-drain low until buck output is within ±10% of target - provides deterministic system power sequencing without external comparators. |
Applications
| Fault-Protected Sensor Supply | Automotive Power Management |
|---|---|
Use Scenario: Powering MEMS pressure sensors in engine control units where supply must track ASIC reference under load dump and reverse battery conditions. IC Role / Device Role / Timing Role: Triple-output PMIC providing synchronized 6V buck and dual 5V LDOs with ±45V fault tolerance on all LDO inputs and outputs. Use Value: Eliminates six external protection components (TVS, reverse diodes, current-limit resistors) while maintaining <15mV ripple and ±6mV tracking accuracy. | Use Scenario: Generating clean, sequenced rails for infotainment SoCs requiring isolated 3.3V I/O, 1.8V core, and 5V USB PHY from a 12V battery input. IC Role / Device Role / Timing Role: Primary power source delivering 400mA buck output and two independently enabled 200mA LDOs with programmable current limits. Use Value: Enables single-chip solution with PG signaling for safe boot sequencing and thermal shutdown at 150°C junction temperature. |
| Portable Instrumentation Power | Industrial Process Monitoring |
Use Scenario: Battery-powered handheld multimeter requiring ultra-low quiescent current, low-noise analog rails, and robust ESD protection on sensor interface lines. IC Role / Device Role / Timing Role: System power manager supplying 5V analog front-end and 3.3V digital logic from Li-ion (3.0–4.2V) via buck-boost-capable input range. Use Value: 50µA no-load IQ extends battery life; 10µF ceramic output caps minimize board area; ±45V LDO pin ratings absorb ESD strikes on sensor cables. | Use Scenario: 4–20mA loop-powered transmitter needing isolated, low-drift 5V and 3.3V rails for ADC, DAC, and microcontroller - operating in ambient temperatures up to 85°C. IC Role / Device Role / Timing Role: Precision tracking regulator ensuring sensor excitation voltage matches measurement ASIC supply within 0.1% across temperature. Use Value: ±6mV tracking error over –40°C to 125°C eliminates calibration drift; 200mA LDO output drives high-side current sense amplifier without droop. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar triple-output power management applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3676IUF#PBF | Quad-output PMIC (3x buck + 1x LDO); no LDO tracking; 2.5V–5.5V input; 1.2A max buck current | Targets low-voltage portable SoCs; lacks ±45V fault protection and tracking capability | Select when higher buck current and multiple buck outputs are needed, but tracking and high-voltage tolerance are not required. |
| TPS65218D0RSLR | PMIC for AM335x processors; fixed 1.5V/1.8V/3.3V outputs; 2.7V–5.5V input; no programmable LDOs | Application-specific for TI Sitara; no external ADJ pin, no fault protection beyond 6V | Choose only for AM335x-based designs requiring pre-configured rails and integrated charger - not a functional substitute for LT3668IMSE#TRPBF. |
Compared with LTC3676IUF#PBF and TPS65218D0RSLR, the LT3668IMSE#TRPBF uniquely combines high-input-voltage buck regulation, dual tracking LDOs with ±45V fault tolerance, and programmable current limiting - making it irreplaceable for sensor-ASIC power tracking in automotive and industrial environments where voltage transients and precision matching are critical.
Availability
LT3668IMSE#TRPBF is available at Aetrix Electronics and suitable for automotive power management, industrial process monitoring, and portable instrumentation requiring stable component supply across extended temperature ranges and harsh electrical environments.
Supply support for LT3668IMSE#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, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, formed through the acquisition of Linear Technology in 2017.
The LT3668 product line was developed by Linear Technology specifically for high-reliability, fault-tolerant power management in sensor interface and measurement systems - emphasizing tracking accuracy, wide input range, and robust protection.
FAQ
What is the maximum input voltage the LT3668IMSE#TRPBF can withstand continuously?
The LT3668IMSE#TRPBF supports continuous operation up to 40V on the IN1 pin, with overvoltage lockout triggering at 42V (typical). It can safely sustain non-repetitive 60V transients for up to 1 second - a key specification for automotive 12V/24V systems experiencing load dump events. This rating is confirmed in the Absolute Maximum Ratings table of the official datasheet.
How does the LT3668IMSE#TRPBF achieve ±45V fault protection on its LDO pins?
The LT3668IMSE#TRPBF achieves ±45V fault protection on ADJ2, ADJ3, OUT2, OUT3, and IN2 pins through internal clamp structures and robust ESD cell design - verified in Absolute Maximum Ratings. This eliminates need for external TVS diodes in applications exposed to reverse battery, inductive kickback, or ESD. The protection applies to both absolute pin voltage and differential voltage (e.g., OUT2–IN2 ≤ ±45V).
Can the LT3668IMSE#TRPBF operate with only one LDO enabled?
Yes, the LT3668IMSE#TRPBF supports independent enable/disable of each LDO via the EN2/ILIM2 and EN3/ILIM3 pins. Pulling either pin above 1.2V disables its corresponding LDO while the buck regulator and other LDO remain fully operational. Quiescent current drops to ~13µA (IN2) or ~25µA (IN3/BD) when disabled - confirmed in Electrical Characteristics tables.
What is the minimum output capacitor required for stable operation of the LT3668IMSE#TRPBF LDOs?
The LT3668IMSE#TRPBF LDOs require a minimum 10µF ceramic output capacitor on each OUT2 and OUT3 pin for stability - explicitly stated in the PIN FUNCTIONS section and validated in Typical Performance Characteristics (G26–G27). Lower values risk oscillation; X5R/X7R dielectrics are recommended for temperature stability across –40°C to 125°C.
Does the LT3668IMSE#TRPBF support adjustable switching frequency, and how is it set?
Yes, the LT3668IMSE#TRPBF supports adjustable switching frequency from 250kHz to 2.2MHz using an external resistor from the RT pin to GND. Table 1 in the datasheet specifies exact values (e.g., 174kΩ for 600kHz). Frequency selection impacts efficiency, inductor size, and minimum dropout - trade-offs detailed in the APPLICATIONS INFORMATION section.
LT3668IMSE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Topology:
- Step-Down (Buck) (1), Linear (LDO) (2)
- Number of Outputs:
- 3
- Frequency - Switching:
- 250kHz ~ 2.2MHz
- Voltage/Current - Output 1:
- 1.2V ~ 39.4V, 400mA
- Voltage/Current - Output 2:
- 1.1V ~ 10V, 200mA
- Voltage/Current - Output 3:
- 1.1V ~ 10V, 200mA
- w/LED Driver:
- No
- w/Supervisor:
- No
- w/Sequencer:
- No
- Voltage - Supply:
- 1.6V ~ 40V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-MSOP-EP
LT3668IMSE#TRPBF FAQ
1.How can I place an order for LT3668IMSE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3668IMSE#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 LT3668IMSE#TRPBF reliable?
The price and inventory of LT3668IMSE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3668IMSE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3668IMSE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3668IMSE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3668IMSE#TRPBF?
LT3668IMSE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3668IMSE#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 LT3668IMSE#TRPBF?
For technical support, including LT3668IMSE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3668IMSE#TRPBF requirements.
6.How does Aetrix verify that LT3668IMSE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3668IMSE#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 LT3668IMSE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3668IMSE#TRPBF?
All LT3668IMSE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3668IMSE#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 LT3668IMSE#TRPBF part is unused and in its original packaging.
Return procedure for LT3668IMSE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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