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Analog Devices Inc. LT3759IMSE#PBF
- Part No.:
- LT3759IMSE#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 12-TSSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3759IMSE#PBF.pdf
- Description:
- IC REG CTRLR MULT TOP 12MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:5,673
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Product details
Overview
LT3759IMSE#PBF from Analog Devices (formerly Linear Technology) is a wide-input, current-mode DC/DC controller for boost, SEPIC, and inverting topologies. It regulates positive or negative outputs from a single FBX pin, supports 1.6V–42V input, delivers up to 2A output current, features 50mV SENSE threshold, programmable 100kHz–1MHz switching, and PGOOD status reporting-ideal for automotive post-regulation and industrial distributed supplies.
For engineers reviewing the LT3759IMSE#PBF datasheet, LT3759IMSE#PBF pinout, LT3759IMSE#PBF application, or LT3759IMSE#PBF equivalent, key selection considerations include its dual-polarity feedback architecture, INTVCC dual-LDO power sourcing (VIN or DRIVE), soft-start programmability, frequency synchronization capability, and exposed-pad MSOP-12 thermal performance.
Technical Context
The LT3759IMSE#PBF implements fixed-frequency current-mode control with dual error amplifiers-one for +1.6V regulation (positive output), one for –0.8V regulation (negative output)-selected automatically by FBX voltage polarity. Its PWM comparator integrates slope compensation and senses peak switch current via the SENSE pin with 50mV threshold.
It integrates two independent LDOs: DRIVE LDO (4.75V output, powered from DRIVE pin) and VIN LDO (3.75V output, powered from VIN), both feeding INTVCC; internal logic selects the active LDO based on supply voltages and dropout conditions. The PGOOD pin reports output voltage status using window comparators referenced to FBX regulation points with ±5% tolerance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 1.6V to 42V - supports direct connection to automotive battery (cold-crank down to ~4V) and industrial rails without pre-regulation. |
| Output Polarity Support | Positive or negative - enabled by single FBX pin with auto-selecting dual error amplifiers; eliminates need for separate controllers per polarity. |
| SENSE Threshold | 50mV (typical) - enables accurate current limiting with low-value, low-power sense resistors; reduces power loss and PCB footprint. |
| Switching Frequency | 100kHz to 1MHz - set by RT resistor or synchronized externally; allows trade-off between efficiency (lower f) and magnetics size (higher f). |
| PGOOD Accuracy | ±5% of regulation voltage - indicates valid output within 80mV (for +1.6V) or 40mV (for –0.8V); enables reliable system power sequencing. |
| Shutdown Current | <1µA - achieved when EN/UVLO ≤ 0.4V; critical for always-on automotive modules requiring ultra-low quiescent drain. |
| Package | 12-Lead MSOP with exposed pad - θJA ≈ 40°C/W with proper PCB copper pour; enables high-power density in space-constrained designs. |
Pinout & Package
LT3759IMSE#PBF is housed in a 12-lead plastic MSOP package with exposed pad (Pin 13), which must be soldered to PCB ground for thermal and electrical integrity. The exposed pad significantly improves thermal dissipation (θJA ≈ 40°C/W) and reduces ground impedance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VC | Error amplifier compensation node | Connect external RC network to stabilize voltage loop; sets bandwidth and phase margin for stable regulation. |
| FBX | Feedback input for +1.6V or –0.8V regulation | Dual-function pin: selects polarity automatically; also hosts PGOOD window comparators and frequency foldback during faults. |
| SS | Soft-start control | 10µA pull-up to 2.5V rail; external capacitor sets ramp time; reset by EN/UVLO or INTVCC UVLO for fault recovery. |
| RT | Frequency programming | Resistor to GND sets oscillator frequency (100kHz–1MHz); open-circuit prohibited-guarantees defined operating point. |
| SYNC | External clock input | Accepts digital clock edge; requires RT set 20% below SYNC frequency; disabled when tied to GND. |
| PGOOD | Open-collector status output | Asserts low when INTVCC > 2.7V and FBX within ±5% of regulation; drives microcontroller enable or system sequencer. |
| EN/UVLO | Enable and input undervoltage detection | 1.22V falling threshold with programmable hysteresis; disables IC and cuts VIN IQ to <1µA under fault. |
| VIN | Main supply and VIN LDO input | Bypass with ≥1µF ceramic near pin; powers internal bias and VIN LDO (3.75V output to INTVCC). |
| DRIVE | DRIVE LDO input | Can be connected to quasi-regulated rail (e.g., converter output); powers DRIVE LDO (4.75V to INTVCC); tie to VIN if unused. |
| GATE | N-MOSFET gate driver output | Sources/sinks current between INTVCC and GND; actively pulls low during shutdown or INTVCC UVLO. |
| SENSE | Current sense input | Kelvin-connected to FET source resistor; compares against 50mV threshold to limit peak switch current. |
| GND | Ground reference and thermal pad | Exposed pad (Pin 13) is GND-must be soldered to large PCB ground plane for thermal and EMI performance. |
Key Features
| Feature | Design Value |
|---|---|
| Dual-polarity regulation | Single FBX pin supports +1.6V or –0.8V reference selection-reduces BOM count and simplifies layout for bipolar supply generation. |
| Programmable soft-start | External capacitor on SS pin controls output voltage ramp rate-prevents inrush current, inductor saturation, and output overshoot at startup. |
| INTVCC dual-LDO architecture | Auto-selects between VIN LDO (3.75V) and DRIVE LDO (4.75V) based on supply conditions-ensures robust gate drive across input transients and topology variations. |
| Accurate PGOOD reporting | Window comparator on FBX with ±5% tolerance relative to regulation voltage-enables deterministic power-good signaling for downstream logic and safety monitoring. |
| Frequency foldback during fault | Reduces switching frequency when FBX nears GND (e.g., short-circuit or start-up)-limits peak inductor current without external circuitry. |
Applications
| Automotive Post-Regulator | Industrial Distributed Supply |
|---|---|
Use Scenario: Regulating 12V battery rail to stable 12V output after alternator transients and cold-crank dips. IC Role / Device Role / Timing Role: Wide-VIN current-mode controller managing SEPIC topology to maintain regulation despite input dropping to 2.5V. Use Value: Maintains 12V/2A output across 2.5V–36V input range; PGOOD confirms rail stability before enabling ADAS subsystems. | Use Scenario: Generating isolated ±15V rails for analog signal conditioning in factory automation I/O modules. IC Role / Device Role / Timing Role: Configured as inverting converter to produce –15V from 24V bus; FBX pin directly references –0.8V internal reference. Use Value: Eliminates need for separate negative-buck controller; 50mV SENSE threshold enables precise current limiting on high-current analog stages. |
| Portable Medical Instrument | Datacom Power Management |
Use Scenario: Powering precision ADC/DAC circuitry in handheld ultrasound devices from single-cell Li-ion (3.0–4.2V). IC Role / Device Role / Timing Role: Boost converter generating 5V rail; soft-start prevents battery sag during startup; low shutdown IQ extends battery life. Use Value: Delivers 5V/1A with <1µA shutdown current; RT-programmed 600kHz operation balances efficiency and compact 2.2µH inductor size. | Use Scenario: Providing 48V-to-12V intermediate bus in telecom line cards with strict EMI requirements. IC Role / Device Role / Timing Role: Synchronized to system clock via SYNC pin to avoid beat frequencies; operates at 400kHz with external RT resistor. Use Value: Enables deterministic switching alignment across multiple converters-reducing conducted EMI peaks and easing filter design. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar DC/DC controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3789EMSE#PBF | 4-switch synchronous buck-boost controller; supports 4V–36V input; no native inverting mode; requires external MOSFETs for all four switches. | Optimized for high-efficiency bidirectional voltage conversion where input may exceed or fall below output; not suitable for simple inverting or SEPIC. | Select LTC3789EMSE#PBF only when synchronous 4-switch operation and bidirectional regulation are required; LT3759IMSE#PBF remains preferred for cost-sensitive SEPIC/inverting designs. |
| LM5122MMX/NOPB | Wide-VIN current-mode controller (3V–65V); supports boost/SEPIC/inverting; lacks dual-polarity FBX architecture-requires external op-amp for negative regulation. | Requires additional components to achieve negative output; PGOOD accuracy ±7.5% vs LT3759IMSE#PBF's ±5%; no integrated frequency foldback. | Choose LM5122MMX/NOPB when input exceeds 42V or when TI ecosystem compatibility is prioritized; LT3759IMSE#PBF offers superior integration for dual-polarity and fault management. |
Compared with LTC3789EMSE#PBF and LM5122MMX/NOPB, the LT3759IMSE#PBF uniquely combines single-pin dual-polarity regulation, integrated frequency foldback, and sub-1µA shutdown current-making it optimal for space- and efficiency-constrained automotive and portable applications requiring flexible topology support.
Availability
LT3759IMSE#PBF is available at Aetrix Electronics and suitable for automotive post-regulators, industrial distributed supplies, and portable medical instrumentation requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT3759IMSE#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, 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 LT3759 product line was designed specifically for wide-input, multi-topology DC/DC control in harsh environments-emphasizing automotive-grade reliability, thermal robustness, and flexible output polarity without added components.
FAQ
What is the operating temperature range for the LT3759IMSE#PBF?
The LT3759IMSE#PBF is specified for operation from –40°C to +125°C junction temperature. This industrial-grade rating ensures reliable performance in under-hood automotive locations, factory-floor industrial equipment, and outdoor telecom enclosures where ambient temperatures exceed standard commercial limits. The exposed-pad MSOP package, when properly soldered to a thermal plane, maintains safe junction temperatures even at full load.
How does the LT3759IMSE#PBF support both positive and negative output voltages?
The LT3759IMSE#PBF uses a dual-error-amplifier architecture referenced to +1.6V and –0.8V internal references. When the FBX pin voltage is above 0V, the positive-reference amplifier activates; when below 0V, the negative-reference amplifier takes control. This automatic selection-enabled by a single resistor divider from output to GND-allows seamless configuration as boost, SEPIC (positive), or inverting (negative) without changing external components or control logic.
Can the LT3759IMSE#PBF be synchronized to an external clock, and what are the requirements?
Yes, the LT3759IMSE#PBF supports synchronization via the SYNC pin. To use this feature, apply a clean digital clock signal with minimum 200ns pulse width to SYNC, and configure the RT resistor to set the internal oscillator frequency 20% lower than the SYNC frequency. The SYNC function is disabled if INTVCC falls below 2.7V or during FBX frequency foldback, ensuring robust operation during faults.
What is the purpose of the dual-LDO architecture (VIN LDO and DRIVE LDO) in the LT3759IMSE#PBF?
The LT3759IMSE#PBF integrates two independent LDOs-VIN LDO (3.75V output) and DRIVE LDO (4.75V output)-to supply INTVCC. The IC automatically selects the active LDO based on input conditions: DRIVE LDO engages when DRIVE voltage is ≥3.9V, otherwise VIN LDO powers INTVCC. This architecture ensures stable gate drive and internal bias across wide input transients and topology configurations, eliminating need for external regulators.
How does the soft-start function work on the LT3759IMSE#PBF, and how is it configured?
The LT3759IMSE#PBF implements soft-start via the SS pin, which sources a 10µA current into an external capacitor. As the SS voltage ramps from 0V to 2.5V, it modulates the VC pin clamp to gradually increase peak switch current and output voltage. Start-up is reset by EN/UVLO undervoltage, INTVCC UVLO, or thermal lockout. The soft-start duration is calculated as TSS = CSS × 1.25V / 10µA, allowing precise control over inrush behavior.
LT3759IMSE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 12-TSSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Up, Step-Up/Step-Down
- Output Configuration:
- Positive or Negative, Isolation Capable
- Topology:
- Boost, Flyback, SEPIC
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 1.6V ~ 42V
- Frequency - Switching:
- 100kHz ~ 1MHz
- Duty Cycle (Max):
- -
- Synchronous Rectifier:
- No
- Clock Sync:
- Yes
- Serial Interfaces:
- -
- Control Features:
- Enable, Frequency Control, Power Good, Soft Start
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 12-MSOP-EP
LT3759IMSE#PBF FAQ
1.How can I place an order for LT3759IMSE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3759IMSE#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 LT3759IMSE#PBF reliable?
The price and inventory of LT3759IMSE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3759IMSE#PBF is usually 5 days.
3.What payment methods are accepted for LT3759IMSE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3759IMSE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3759IMSE#PBF?
LT3759IMSE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3759IMSE#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 LT3759IMSE#PBF?
For technical support, including LT3759IMSE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3759IMSE#PBF requirements.
6.How does Aetrix verify that LT3759IMSE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3759IMSE#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 LT3759IMSE#PBF meets industry standards.
7.What is the process for return or replacement of LT3759IMSE#PBF?
All LT3759IMSE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3759IMSE#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 LT3759IMSE#PBF part is unused and in its original packaging.
Return procedure for LT3759IMSE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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