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Analog Devices Inc. LT3668EMSE#TRPBF
- Part No.:
- LT3668EMSE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Voltage Regulators - Linear + Switching
- Package:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3668EMSE#TRPBF.pdf
- Description:
- IC REG TRIPLE BUCK/LINEAR 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,288
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Product details
Overview
LT3668EMSE#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, tracked outputs for sensor/ASIC supply pairs with ±45V fault protection, 1.6V–45V input range, and 50µA no-load quiescent current - ideal for automotive sensor modules requiring robust, low-noise, trackable dual-rail biasing.
For engineers reviewing the LT3668EMSE#TRPBF datasheet, LT3668EMSE#TRPBF pinout, LT3668EMSE#TRPBF application, or LT3668EMSE#TRPBF equivalent, key selection criteria include its dual programmable-current-limit LDOs with ±6mV tracking error (1.1–5V adj range), 250kHz–2.2MHz adjustable switching frequency, integrated power good indicator, and thermally enhanced 16-lead MSOP package with exposed pad.
Technical Context
The LT3668EMSE#TRPBF employs current-mode PWM control for the buck stage, enabling fast transient response and stable loop behavior across wide load and input ranges. Its internal NPN switch, integrated boost diode, and BOOST capacitor circuitry ensure full saturation at high duty cycles while supporting up to 60V transient input tolerance.
Each LDO uses micropower error amplifiers with precision current mirrors for resistor-programmable limits (e.g., 10mA–197mA), reverse-battery and reverse-output protection, and tracking accuracy maintained over –40°C to 125°C. The LDOs can be powered independently via IN2/IN3/BD, enabling flexible supply sequencing and bias sourcing from regulated outputs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 1.6V to 45V continuous; withstands 60V transients - supports wide automotive battery and industrial input rails. |
| Buck Output Current | 400mA with internal NPN switch - eliminates external MOSFET and reduces BOM count in compact designs. |
| LDO Output Current | 2 × 200mA with <340mV dropout at full load - enables low-voltage operation with minimal headroom loss. |
| Tracking Error | ±6mV (1.1–5V ADJ range, –40°C to 125°C) - ensures sub-0.1% matching between sensor and ASIC supply rails. |
| No-Load Quiescent Current | 50µA total (IN1+IN2, 12V input) in Burst Mode - extends battery life in always-on sensor nodes. |
| Switching Frequency Range | 250kHz to 2.2MHz, set by RT resistor - allows optimization of inductor size vs. efficiency (e.g., 600kHz typical). |
| Fault Protection | ±45V absolute max on ADJ2/ADJ3, OUT2/OUT3, IN2; reverse-battery & reverse-current protection - eliminates need for external TVS or diodes. |
Pinout & Package
LT3668EMSE#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 (DA), and BOOST capacitor - carries high dI/dt switching current. |
| BOOST (2) | Switch driver voltage boost | Requires 0.22µF capacitor to SW - generates >VIN voltage to fully saturate internal NPN switch. |
| EN (3) | Global enable input | Logic-high (>1.1V) enables all regulators; <0.3V disables - draws only 0.6–2µA, supports low-power wake-up. |
| RT (4) | Oscillator frequency set | Resistor to GND sets 250kHz–2.2MHz switching frequency - enables EMI tuning and size/efficiency trade-offs. |
| IN3/BD (5) | LDO3 input / boost diode anode | Supplies LDO3 and powers internal bias regulator when >3.2V - enables self-biasing from regulated output. |
| OUT3 (6) | LDO3 output | 200mA tracked output - requires ≥10µF ceramic capacitor for stability and low noise. |
| ADJ3 (9) | LDO3 tracking reference | Voltage applied here sets OUT3; tracking error ±6mV - enables precise sensor supply following ASIC rail. |
| FB1 (8) | Buck feedback node | Regulated to 1.188–1.224V - sets buck output via resistor divider; determines accuracy and load regulation. |
| IN2 (11) | LDO2 input | Independent input for second LDO - supports separate input source or cascaded supply from OUT2. |
| OUT2 (10) | LDO2 output | 200mA tracked output - identical specs to OUT3; shares same design constraints and capacitor requirements. |
| EN2/ILIM2 (12) | LDO2 enable & current limit | Resistor to GND programs current limit (e.g., 31.6k = 10mA); >1.2V disables LDO2 - integrates control and protection. |
| EN3/ILIM3 (13) | LDO3 enable & current limit | Functionally identical to EN2/ILIM2 - enables independent programming and shutdown of each LDO. |
| PG (14) | Power good open-drain | Active-low when FB1 is within ±10% of target - provides system-level fault detection without external comparators. |
| IN1 (15) | Buck input & bias supply | Main input for buck stage and internal logic - requires local ceramic bypass (e.g., 10µF) near pin. |
| DA (16) | Catch diode anode sense | Monitors catch diode current for foldback protection - prevents thermal runaway during short-circuit events. |
| GND (17) | Power & signal ground | Exposed pad must be soldered to PCB plane - critical for thermal performance (θJA = 40°C/W) and noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| Dual programmable-current-limit LDOs | Each LDO supports resistor-set current limits from 9.5mA to 197mA - enables precise fault current tailoring per sensor channel. |
| ±45V fault protection on all LDO pins | Withstands reverse battery, load dump, and ESD events without external protection components - reduces system cost and board area. |
| Low-noise Burst Mode operation | Maintains <15mVP-P output ripple at light loads while drawing only 50µA - ideal for battery-powered instrumentation. |
| Independent LDO biasing via IN3/BD | Allows LDO3 to power internal bias circuitry when VIN >3.2V - improves efficiency by reducing IN1 current draw. |
| Integrated power good indicator | Open-drain PG pin asserts when buck output is within ±10% of regulation - simplifies system power sequencing and monitoring. |
| Thermally enhanced MSOP-16EP | Exposed pad lowers thermal resistance to 40°C/W - enables 400mA buck + 2×200mA LDOs in compact footprint without heatsink. |
Applications
| Automotive Sensor Modules | Industrial Process Transmitters |
|---|---|
Use Scenario: Powering MEMS pressure sensors and their companion ADC/DSP ASICs in engine control units. IC Role / Device Role / Timing Role: Provides matched 5V sensor supply and 5V ASIC supply with <6mV tracking error, ensuring analog front-end accuracy under temperature variation. Use Value: Eliminates need for discrete LDOs and tracking resistors, reduces layout sensitivity to thermal gradients, and sustains operation during 45V load-dump transients. |
Use Scenario: Supplying 4–20mA loop-powered field transmitters with isolated sensor and microcontroller rails. IC Role / Device Role / Timing Role: Generates 3.3V microcontroller rail from buck stage and 5V sensor rail from LDO2, both referenced to common ground with reverse-battery protection. Use Value: Enables single-supply design with integrated fault protection, meets IEC 61000-4-5 surge immunity without external TVS, and maintains regulation down to 1.6V input. |
| Portable Medical Instrumentation | Test & Measurement Front Ends |
Use Scenario: Biasing low-noise op-amps and precision ADCs in handheld ECG monitors. IC Role / Device Role / Timing Role: Delivers ultra-low-noise 2.5V analog rail (LDO2) and 3.3V digital rail (buck) with 10µVRMS output noise and 50µA quiescent current. Use Value: Extends battery life beyond 72 hours per charge while preserving SNR >100dB in analog signal chain. |
Use Scenario: Powering high-speed comparators and reference buffers in automated test equipment channel cards. IC Role / Device Role / Timing Role: Supplies 1.8V comparator rail (LDO3) and 5V reference buffer rail (LDO2) with <100ns load transient response and ±0.5% line regulation. Use Value: Prevents measurement drift during rapid load changes; eliminates need for post-regulation LC filtering due to inherent low ripple. |
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 |
|---|---|---|---|
| LTC3675EFE#PBF | Quad-output PMIC (3x LDO + 1x buck); 300mA buck; no ±45V fault rating on LDO pins | Lacks fault protection for automotive sensor rails; supports more outputs but lower current per LDO | Choose LTC3675 if needing four independent rails and lower integration density is acceptable. |
| TPS65270PWPR | Dual 2A buck + 300mA LDO; no tracking capability; 28V max input; no LDO fault protection | Higher buck current but no LDO tracking or ±45V tolerance - unsuitable for sensor/ASIC matched biasing | Choose TPS65270 only for high-current non-tracking applications where fault protection is handled externally. |
Compared with LTC3675EFE#PBF and TPS65270PWPR, the LT3668EMSE#TRPBF uniquely combines dual tracking LDOs with ±45V fault tolerance and integrated power good - making it the only option that satisfies stringent automotive sensor supply matching and transient survivability requirements in a single IC.
Availability
LT3668EMSE#TRPBF is available at Aetrix Electronics and suitable for automotive sensor modules, industrial process transmitters, and portable medical instrumentation requiring stable component supply, long-term lifecycle support, and guaranteed -40°C to 125°C operation.
Supply support for LT3668EMSE#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, serving industrial, automotive, communications, and healthcare markets.
The LT3668EMSE#TRPBF belongs to Linear's µPower monolithic power management family, designed specifically for space-constrained, fault-tolerant applications where matched, protected, low-noise dual-rail supplies are required - such as automotive sensor nodes and precision instrumentation.
FAQ
What is the maximum input voltage the LT3668EMSE#TRPBF can withstand without damage?
The LT3668EMSE#TRPBF supports continuous operation up to 45V on IN1, with absolute maximum ratings of ±45V on ADJ2/ADJ3, OUT2/OUT3, and IN2 pins, and 60V transient tolerance on IN1 for ≤1 second. This enables direct connection to 42V automotive systems and robustness against load-dump events without external protection components.
How is output voltage tracking accuracy specified for the LT3668EMSE#TRPBF LDOs?
The LT3668EMSE#TRPBF specifies tracking error as ±6mV for VADJ2/3 = 1.1V to 5V at –40°C to 125°C, and ±15mV for 5V < VADJ2/3 ≤ 10V over the same range. This translates to better than 0.12% matching for a 5V reference - critical for maintaining signal integrity between sensor and processing ASIC supplies.
Can the LT3668EMSE#TRPBF operate with only one LDO enabled?
Yes. Each LDO (OUT2 and OUT3) can be independently disabled by pulling its respective EN2/ILIM2 or EN3/ILIM3 pin above 1.2V. When disabled, quiescent current drops to 13µA (LDO2) or 1.2µA (LDO3), and the corresponding output goes to zero. The buck regulator remains fully functional regardless of LDO state.
What is the minimum output capacitor required for stability of the LT3668EMSE#TRPBF LDOs?
The LT3668EMSE#TRPBF LDOs require a minimum 10µF ceramic output capacitor on each OUT2 and OUT3 pin for stability, as confirmed in the datasheet's "Stability Requirements" section. Using smaller or non-ceramic capacitors may cause oscillation or degraded transient response, especially under 200mA load steps.
Does the LT3668EMSE#TRPBF support adjustable switching frequency, and how is it set?
Yes. The LT3668EMSE#TRPBF supports 250kHz to 2.2MHz adjustable switching frequency via an external resistor (RT) from Pin 4 to GND. For example, 174kΩ sets 600kHz, 95.3kΩ sets 1MHz, and 37.4kΩ sets 2MHz - enabling optimization of inductor size, efficiency, and EMI profile per application.
LT3668EMSE#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
LT3668EMSE#TRPBF FAQ
1.How can I place an order for LT3668EMSE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3668EMSE#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 LT3668EMSE#TRPBF reliable?
The price and inventory of LT3668EMSE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3668EMSE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3668EMSE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3668EMSE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3668EMSE#TRPBF?
LT3668EMSE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3668EMSE#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 LT3668EMSE#TRPBF?
For technical support, including LT3668EMSE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3668EMSE#TRPBF requirements.
6.How does Aetrix verify that LT3668EMSE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3668EMSE#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 LT3668EMSE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3668EMSE#TRPBF?
All LT3668EMSE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3668EMSE#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 LT3668EMSE#TRPBF part is unused and in its original packaging.
Return procedure for LT3668EMSE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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