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Analog Devices Inc. LT3668HMSE#TRPBF
- Part No.:
- LT3668HMSE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Voltage Regulators - Linear + Switching
- Package:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3668HMSE#TRPBF.pdf
- Description:
- IC REG TRIPLE BUCK/LINEAR 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,095
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Product details
Overview
LT3668HMSE#TRPBF from Analog Devices (formerly Linear Technology) is a monolithic triple-output power management IC comprising a 400mA buck switching regulator and two 200mA fault-protected low-dropout linear tracking regulators. It delivers 6V/400mA, 5V/200mA, and 5V/200mA outputs from a single 7V–40V input, with ±45V fault protection on LDO inputs/outputs and 1.6V minimum LDO input voltage - enabling robust sensor-ASIC power supply tracking in automotive engine control units.
For engineers reviewing the LT3668HMSE#TRPBF datasheet, LT3668HMSE#TRPBF pinout, LT3668HMSE#TRPBF application, or LT3668HMSE#TRPBF equivalent, key selection considerations include its –40°C to 150°C H-grade junction temperature rating, programmable 250kHz–2.2MHz switching frequency, 340mV typical dropout at 200mA per LDO, 50μA no-load quiescent current, and dual resistor-programmable current limits for precise overcurrent protection.
Technical Context
The LT3668HMSE#TRPBF integrates current-mode PWM control for the buck stage with independent micropower error amplifiers and current-limit amplifiers for each LDO. Its architecture enables tight output tracking (±6mV typical at 1mA load, –40°C to 150°C) between LDO outputs and external ADJ2/ADJ3 reference voltages, while internal slope compensation ensures stable operation across duty cycles.
Burst Mode® operation maintains <15mVP-P output ripple at light loads by disabling non-essential circuitry, and the integrated boost capacitor drive (0.22μF), catch diode sense (DA pin), and power-good window comparator (±10% FB1 regulation threshold) provide complete system-level fault monitoring without external components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Operating Junction Temp | –40°C to 150°C (H-grade, validated for under-hood automotive) |
| Buck Output Current | 400mA max with internal NPN switch and integrated boost diode drive |
| LDO Output Current | 200mA per channel with resistor-programmable current limit (9.5–230mA range) |
| Input Voltage Range | 4.3V to 40V for buck; 1.6V to 45V for LDOs; fault protected to ±45V |
| Quiescent Current | 50μA total (IN1+IN2+IN3/BD) at 12VIN, 6V/5V outputs, no load |
| Tracking Error | ±6mV (1.1–5V ADJ range, 1mA load, –40°C to 150°C) |
| Switching Frequency | 250kHz to 2.2MHz, set by RT pin resistor (32.4kΩ to 475kΩ) |
| Dropout Voltage | 340mV typical at 200mA per LDO (measured at VIN – VOUT) |
Pinout & Package
The LT3668HMSE#TRPBF is housed in a thermally enhanced 16-lead MSOP package with exposed pad (Pin 17 = GND), θJA = 40°C/W. The exposed pad must be soldered to PCB for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (1) | Buck switch node | Connects to inductor, catch diode anode (via DA), and boost capacitor - carries high di/dt switching current |
| BOOST (2) | Switch driver bootstrap | Drives internal NPN switch via 0.22μF capacitor to SW; enables full saturation at high input voltages |
| EN (3) | Global enable | Logic-level shutdown input; <0.3V disables all regulators, <1μA shutdown current |
| RT (4) | Oscillator frequency set | Resistor-to-GND sets 250kHz–2.2MHz switching frequency; determines inductor size and efficiency trade-off |
| IN3/BD (5) | LDO3 input / boost diode anode | Supplies LDO3 and powers internal bias regulator when >3.2V - improves system efficiency |
| OUT3 (6) | LDO3 regulated output | 200mA tracking output referenced to ADJ3; requires ≥10μF ceramic output capacitor |
| ADJ3 (9) | LDO3 tracking reference | Voltage applied here sets OUT3; tracking error ±6mV over full temp range |
| FB1 (8) | Buck feedback node | Regulated to 1.2V ±1.2%; connects to resistor divider for output voltage programming |
| IN2 (11) | LDO2 input | Independent 1.6V–45V input for second tracking LDO; fault protected to ±45V |
| OUT2 (10) | LDO2 regulated output | 200mA tracking output referenced to ADJ2; same stability requirements as OUT3 |
| EN2/ILIM2 (12) | LDO2 enable / current limit | Resistor-to-GND programs current limit (9.5–230mA); >1.2V disables LDO2 |
| EN3/ILIM3 (13) | LDO3 enable / current limit | Resistor-to-GND programs current limit (9.5–230mA); >1.2V disables LDO3 |
| PG (14) | Power good indicator | Open-drain output active-low when FB1 is outside ±10% of 1.2V - signals valid buck regulation |
| IN1 (15) | Buck input | Main 4.3–40V input for buck regulator and internal bias; requires local ceramic bypass |
| DA (16) | Catch diode current sense | Senses D1 current to trigger frequency foldback during overload - protects against short-circuit |
| GND (17) | Power and signal ground | Exposed pad; must be soldered to PCB plane for thermal dissipation and noise control |
Key Features
| Feature | Design Value |
|---|---|
| Fault-protected LDO inputs/outputs | Withstands ±45V transients on IN2, OUT2, ADJ2, IN3/BD, OUT3, ADJ3 - eliminates need for external TVS |
| Triple-output integration | Single-chip solution replaces discrete buck + dual LDOs - reduces BOM count, layout area, and interconnect noise |
| Programmable LDO current limit | Two independent resistor-programmable limits (9.5–230mA) with 47nF capacitor stabilization - enables precise fault current setting |
| H-grade temperature rating | –40°C to 150°C guaranteed operation - qualified for engine compartment and industrial control environments |
| Burst Mode® efficiency | Maintains <15mVP-P ripple and 50μA no-load current - extends battery life in portable instrumentation |
| Tracking accuracy | ±6mV tracking error (1.1–5V ADJ range, 1mA load, full temperature range) - ensures matched sensor/ASIC supply rails |
Applications
| Automotive Engine Control Unit (ECU) | Industrial Sensor Signal Conditioning |
|---|---|
Use Scenario: Powering MEMS pressure sensor and analog front-end ASIC in diesel engine ECU where ambient temperature reaches 150°C. IC Role / Device Role / Timing Role: LT3668HMSE#TRPBF provides tightly tracked 5V sensor supply and 5V ASIC supply from 12V battery rail, with ±45V load dump tolerance. Use Value: Eliminates separate LDOs and fault protection components; H-grade rating avoids derating or thermal throttling at 150°C junction. |
Use Scenario: Supplying precision ADC and temperature sensor in factory-floor vibration monitor exposed to 40V transients. IC Role / Device Role / Timing Role: LT3668HMSE#TRPBF delivers clean, low-noise 3.3V buck output and two 2.5V tracking LDOs from 24V industrial bus. Use Value: Integrated ±45V fault protection prevents field failures; 10μF ceramic output caps minimize board space vs. electrolytic alternatives. |
| Portable Medical Instrumentation | Test & Measurement Equipment |
Use Scenario: Battery-powered handheld blood glucose meter requiring ultra-low quiescent current and stable dual-rail analog supply. IC Role / Device Role / Timing Role: LT3668HMSE#TRPBF generates 3.3V microcontroller rail and 2.5V precision reference rail from single Li-ion cell (3.0–4.2V). Use Value: 50μA no-load IQ extends battery runtime; Burst Mode® maintains <15mV ripple without external LDO post-regulation. |
Use Scenario: Benchtop oscilloscope power subsystem needing isolated, low-noise analog and digital supplies with fast transient response. IC Role / Device Role / Timing Role: LT3668HMSE#TRPBF supplies 1.8V FPGA core, 3.3V I/O, and 5V analog from 12V DC input with independent LDO tracking. Use Value: Dual LDOs track reference voltages to suppress supply-induced crosstalk; 200mA per LDO supports multiple analog stages. |
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 |
|---|---|---|---|
| LT3668EMSE#TRPBF | Same functionality but rated for –40°C to 125°C junction temperature; lower max operating temperature | Suitable for cabin electronics or non-under-hood automotive use where 150°C rating is unnecessary | Select when cost sensitivity outweighs extended temperature requirement and thermal margin is sufficient |
| LT3668IMSE#TRPBF | Identical electrical specs and package; guaranteed performance over –40°C to 125°C (I-grade screening) | Preferred for industrial automation where 125°C ambient is maximum expected, with tighter parametric binning | Choose for cost-optimized industrial designs requiring guaranteed 125°C operation without H-grade premium |
Compared with LT3668EMSE#TRPBF and LT3668IMSE#TRPBF, the LT3668HMSE#TRPBF uniquely supports continuous operation up to 150°C junction temperature - critical for engine bay placement - while retaining identical pinout, footprint, and electrical behavior across all three variants.
Availability
LT3668HMSE#TRPBF is available at Aetrix Electronics and suitable for automotive engine control, industrial sensor conditioning, and portable medical instrumentation requiring stable component supply across extended temperature ranges and high-reliability fault protection.
Supply support for LT3668HMSE#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. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors for precision signal chain and power applications.
The LT3668 product line was designed specifically for fault-tolerant multi-rail power systems in harsh environments - integrating buck conversion, tracking LDOs, and comprehensive protection into a single MSOP package for sensor-ASIC co-location.
FAQ
What is the maximum continuous input voltage rating for the LT3668HMSE#TRPBF buck regulator?
The LT3668HMSE#TRPBF buck regulator has a continuous input voltage rating of 40V on the IN1 pin, with overvoltage lockout triggering at 42V (typical). It can withstand nonrepetitive 1-second transients up to 60V, making it suitable for 42V automotive systems and industrial 48V buses where load dump events occur.
How does the LT3668HMSE#TRPBF achieve ±45V fault protection on its LDO pins?
The LT3668HMSE#TRPBF achieves ±45V fault protection on IN2, OUT2, ADJ2, IN3/BD, OUT3, and ADJ3 through integrated high-voltage clamp structures and reverse-battery protection circuitry - not external components. This is validated per Absolute Maximum Ratings and allows direct connection to unregulated sources subject to load dump or polarity reversal.
Can the LT3668HMSE#TRPBF operate with only one LDO enabled while the other is disabled?
Yes, the LT3668HMSE#TRPBF supports independent LDO control: pulling EN2/ILIM2 or EN3/ILIM3 above 1.2V disables the corresponding LDO. When disabled, that LDO draws only 13μA (IN2) or 1.2μA (IN3/BD) quiescent current, and its output is high-impedance - enabling flexible power sequencing in multi-rail systems.
What is the minimum output capacitor required for stable operation of the LT3668HMSE#TRPBF LDOs?
The LT3668HMSE#TRPBF LDOs require a minimum 10μF ceramic output capacitor on each OUT2 and OUT3 pin for stability, as specified in the datasheet. Using smaller values or non-ceramic types (e.g., tantalum or aluminum electrolytic) may cause oscillation or degraded transient response due to insufficient phase margin.
Does the LT3668HMSE#TRPBF support synchronization to an external clock?
No, the LT3668HMSE#TRPBF does not support external clock synchronization. Its switching frequency is set solely by the RT pin resistor (250kHz–2.2MHz range) and operates in free-running constant-frequency PWM mode. For synchronized multi-phase designs, a different controller such as the LTC389x family would be required.
LT3668HMSE#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 ~ 150°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-MSOP-EP
LT3668HMSE#TRPBF FAQ
1.How can I place an order for LT3668HMSE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3668HMSE#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 LT3668HMSE#TRPBF reliable?
The price and inventory of LT3668HMSE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3668HMSE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3668HMSE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3668HMSE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3668HMSE#TRPBF?
LT3668HMSE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3668HMSE#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 LT3668HMSE#TRPBF?
For technical support, including LT3668HMSE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3668HMSE#TRPBF requirements.
6.How does Aetrix verify that LT3668HMSE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3668HMSE#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 LT3668HMSE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3668HMSE#TRPBF?
All LT3668HMSE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3668HMSE#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 LT3668HMSE#TRPBF part is unused and in its original packaging.
Return procedure for LT3668HMSE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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