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Analog Devices Inc. LTC3256HMSE#TRPBF
- Part No.:
- LTC3256HMSE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Voltage Regulators - Linear + Switching
- Package:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LTC3256HMSE#TRPBF.pdf
- Description:
- IC REG DL BUCK/LINEAR 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,075
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Product details
Overview
LTC3256HMSE#TRPBF from Analog Devices (formerly Linear Technology) is a wide-input, dual-output switched-capacitor DC/DC converter with integrated watchdog timer and power-good monitoring. It delivers regulated 5V (100mA max) and 3.3V (250mA max) outputs from 5.5V–38V input, using automatic 2:1/1:1 charge pump mode switching to maximize efficiency-reducing power dissipation by >2W vs dual-LDO solutions at 12VIN and full load. It serves as a housekeeping supply in automotive ECUs and industrial controllers requiring high reliability and diagnostic coverage.
For engineers reviewing the LTC3256HMSE#TRPBF datasheet, LTC3256HMSE#TRPBF pinout, LTC3256HMSE#TRPBF application, or LTC3256HMSE#TRPBF equivalent, key selection criteria include its 150°C max junction temperature rating, buffered 1.1V reference for system self-test, independent enable control for each output, overcurrent/overtemperature protection, and ISO 26262 diagnostic coverage support.
Technical Context
The LTC3256HMSE#TRPBF implements a multimode step-down charge pump pre-regulator that automatically selects between 2:1 (VIN/2) and 1:1 (VIN) operation based on input voltage and load conditions-maintaining regulation while minimizing power loss. Its 5V output is sourced either from the charge pump output (via fault-protected PMOS switch when VIN > ~10.1V) or directly from VIN via an internal 1:1 regulator when VIN drops below that threshold.
It integrates independent power-good comparators (PG3/PG5), a reset controller with adjustable timeout (RT pin), and a watchdog timer (WT/WDI pins) with programmable upper/lower boundaries. The buffered 1.1V reference (REFOUT) provides low-impedance, temperature-stable voltage for safety-critical diagnostics, and all logic inputs tolerate 38V transients.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 5.5V to 38V - supports automotive battery transients and industrial unregulated rails without external protection. |
| 5V Output Current | Up to 100mA - regulated via charge pump output or VIN-powered 1:1 switch; includes overvoltage/undervoltage fault detection. |
| 3.3V LDO Output Current | Up to 250mA - powered exclusively by OUTCP; maintains regulation down to 3.6V OUTCP in 2:1 mode. |
| Quiescent Current | 20µA (both outputs regulating, no load) - enables always-on monitoring in low-power systems. |
| Junction Temperature Max | 150°C - rated for harsh environments; thermal shutdown activates above this limit. |
| Reference Output | 1.1V ±32mV (0mA load) - buffered bandgap reference with 2kΩ output impedance for accurate system diagnostics. |
| Watchdog Timeout | Internal: 37.5–62.5ms lower / 1.3–2s upper boundary - ensures timely fault recovery without external timing components. |
Pinout & Package
The LTC3256HMSE#TRPBF is housed in a thermally enhanced 16-lead MSOP package with exposed GND pad (MSE16), requiring soldering of the exposed pad to PCB ground for thermal performance (θJA = 40°C/W, θJC = 10°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| C– (1) | Flying capacitor negative terminal | Connects to negative side of external ceramic flying capacitor (≥0.4µF, ≥6V); critical for charge pump energy transfer. |
| C+ (2) | Flying capacitor positive terminal | Connects to positive side of flying capacitor; forms charge transfer path with C– during clock phases. |
| OUTCP (3) | Charge pump output | Regulated ~5.05V output; powers both OUT5 switch and OUT3 LDO; requires ≥10µF X7R ceramic bypass. |
| OUT5 (4) | 5V regulated output | Delivers up to 100mA; enabled by EN5; sourced from OUTCP (2:1 mode) or VIN (1:1 mode) depending on input voltage. |
| REFOUT (5) | Buffered 1.1V reference | Low-impedance diagnostic reference; must be bypassed with 0.1µF ceramic for optimal PSRR. |
| OUT3 (6) | 3.3V LDO output | Delivers up to 250mA; enabled by EN3; powered only by OUTCP; includes PG3 monitoring. |
| PG3 (7) | 3.3V power-good open-drain | Asserts high-impedance when OUT3 reaches 97.5% of regulation; requires external pull-up to OUT3/OUT5/OUTCP. |
| PG5 (8) | 5V power-good open-drain | Asserts high-impedance when OUT5 reaches regulation; undervoltage threshold = 4.6–4.75V, overvoltage = 5.1–5.4V. |
| RST (9) | Reset open-drain output | Drives low during reset timeout (150–260ms internal, adjustable via RT); requires external pull-up. |
| WT (10) | Watchdog timer control | External capacitor sets upper timeout boundary; tie to OUTCP for ~1.6s default; grounding disables watchdog. |
| RT (11) | Reset timeout control | External capacitor sets reset duration; open for ~200ms default; tie to OUTCP for fixed 200ms timeout. |
| RSTI (12) | Reset input comparator | Triggers reset when voltage falls below 1.1–1.26V threshold; used for external system fault signaling. |
| WDI (13) | Watchdog input | Must be toggled within watchdog window (37.5ms–2s); floating or static state asserts RST; grounding disables. |
| VIN (14) | Main power input | Accepts 5.5V–38V; powers internal circuitry and charge pump; requires ≥10µF low-ESR ceramic bypass. |
| EN3 (15) | 3.3V output enable | Logic-high enables OUT3 and starts charge pump; 1µA internal pull-down; 38V tolerant. |
| EN5 (16) | 5V output enable | Logic-high enables OUT5 and starts charge pump; 1µA internal pull-down; 38V tolerant. |
| GND (Exposed Pad) | Ground reference & thermal path | Must be soldered to PCB ground plane; primary thermal conduction path; electrically connected to all internal grounds. |
Key Features
| Feature | Design Value |
|---|---|
| Automated 2:1/1:1 charge pump mode switching | Maximizes efficiency across 5.5V–38V input range without user intervention; avoids thermal derating in 12V automotive systems. |
| Independent output enable (EN3/EN5) | Enables flexible power sequencing-e.g., bring up 3.3V LDO first, then 5V output-reducing inrush and enabling partial system operation. |
| Integrated watchdog timer with dual boundaries | Prevents software lockup by requiring WDI toggling within strict time windows (e.g., 37.5ms–2s), eliminating need for external watchdog ICs. |
| Buffered 1.1V reference (REFOUT) | Provides stable, low-noise reference for ADC calibration or safety-critical self-test routines without loading internal bandgap. |
| ISO 26262 diagnostic coverage support | Includes built-in fault monitors (PG3/PG5, overcurrent, overtemperature, RSTI, WDI), enabling ASIL-B system compliance with minimal external components. |
| 38V input transient tolerance | Withstands automotive load-dump events without external TVS, reducing BOM count and board space in ECU designs. |
Applications
| Automotive ECU Housekeeping Supply | Industrial PLC I/O Module Power |
|---|---|
Use Scenario: Providing isolated 5V and 3.3V rails for microcontroller, CAN transceiver, and sensor interface in engine control units operating from 9V–16V battery with 38V transients. IC Role / Device Role / Timing Role: Dual-output DC/DC converter with integrated watchdog and power-good signals; acts as primary housekeeping supply with diagnostic readiness. Use Value: Eliminates need for two discrete LDOs and external watchdog, reduces power dissipation by >2W at full load, and supports ISO 26262 ASIL-B requirements via built-in fault detection. | Use Scenario: Generating stable 3.3V for FPGA configuration and 5V for relay drivers in modular industrial PLC backplanes with 24V DC input. IC Role / Device Role / Timing Role: Wide-input step-down converter with independent output control; supplies critical logic and actuation rails with coordinated power sequencing. Use Value: Enables single-chip solution for dual-rail generation across varying input voltages (18V–32V), simplifies thermal design with 150°C rating, and provides REFOUT for real-time voltage margining. |
| Telecom Base Station Management | Safety-Critical Medical Monitor Power |
Use Scenario: Delivering 3.3V for baseband processor and 5V for optical transceiver bias in remote radio units exposed to wide ambient temperatures (−40°C to +85°C). IC Role / Device Role / Timing Role: High-reliability dual-output regulator with extended temperature grade (H-grade: −40°C to +150°C); provides power-good status and reset coordination. Use Value: Ensures uninterrupted operation under thermal stress; PG3/PG5 enable safe boot sequencing; watchdog prevents firmware hangs during field updates. | Use Scenario: Powering patient monitoring subsystems (ECG front-end, display controller) requiring redundant voltage supervision and self-test capability per IEC 62304. IC Role / Device Role / Timing Role: Diagnostic-ready power management IC; REFOUT feeds ADC reference channel for continuous rail integrity verification. Use Value: Meets Class C software safety requirements via hardware-enforced watchdog, power-good assertion, and buffered reference for automated self-diagnosis. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-output wide-input regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3255HMSE#TRPBF | Single 3.3V output (250mA), no 5V rail or watchdog timer; same package and temp grade. | Lacks dual-rail capability and safety features-suitable only where 3.3V-only supply suffices. | Select when system requires only one regulated output and diagnostic functions are handled externally. |
| MAX17504ATP+T | Inductor-based synchronous buck (5V/3.3V dual output), higher peak efficiency (>92%), but requires external inductors and lacks integrated watchdog/REFOUT. | Higher EMI, larger footprint, no built-in safety monitoring-requires additional ICs for ISO 26262 compliance. | Choose for highest efficiency in space-tolerant designs where external magnetics and discrete safety circuitry are acceptable. |
Compared with LTC3255HMSE#TRPBF and MAX17504ATP+T, the LTC3256HMSE#TRPBF uniquely combines dual fixed outputs, inductorless operation, integrated watchdog, buffered reference, and automotive-grade thermal rating in a single MSE16 package-making it optimal for compact, safety-conscious, wide-input applications where board area and component count are constrained.
Availability
LTC3256HMSE#TRPBF is available at Aetrix Electronics and suitable for automotive ECU supplies, industrial PLC housekeeping, and telecom base station management requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LTC3256HMSE#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 acquired Linear Technology in 2017 and continues to develop and support its high-performance analog and power management portfolio.
The LTC3256HMSE#TRPBF belongs to Linear's precision power management product line, engineered specifically for automotive and industrial applications demanding high reliability, diagnostic coverage, and operation across extreme input voltage and temperature ranges.
FAQ
What is the maximum junction temperature rating for the LTC3256HMSE#TRPBF?
The LTC3256HMSE#TRPBF is rated for a maximum junction temperature of 150°C, confirmed by its H-grade temperature specification (−40°C to +150°C). This allows reliable operation in under-hood automotive environments and high-ambient industrial settings. Thermal derating applies above 125°C, and the exposed pad must be soldered to PCB ground to achieve the specified θJA = 40°C/W.
How does the LTC3256HMSE#TRPBF handle input voltage transitions between 2:1 and 1:1 charge pump modes?
The LTC3256HMSE#TRPBF automatically switches between 2:1 (VIN/2) and 1:1 (VIN) charge pump modes based on real-time VIN and load conditions-no external control required. When VIN exceeds ~10.1V, it operates in 2:1 mode for highest efficiency; below ~7.2V, it enters 1:1 mode to maintain 3.3V LDO regulation. The transition region (~7.2V–10.1V) uses intermediate regulation to stay in 2:1 mode as long as possible.
Can the LTC3256HMSE#TRPBF's 5V output be used independently of the 3.3V output?
Yes-the LTC3256HMSE#TRPBF supports fully independent enable control via EN5 and EN3. Enabling EN5 alone activates the 5V output (OUT5) and the underlying charge pump; EN3 can remain low to keep the 3.3V LDO (OUT3) disabled. Each output has its own power-good signal (PG5/PG3), allowing separate sequencing and fault monitoring.
What is the purpose of the REFOUT pin on the LTC3256HMSE#TRPBF, and how should it be used?
The REFOUT pin on the LTC3256HMSE#TRPBF delivers a buffered 1.1V ±32mV reference voltage for system-level diagnostics and self-test. It features 2kΩ output impedance and must be bypassed with a 0.1µF ceramic capacitor. In safety-critical applications, REFOUT feeds ADC channels to verify rail integrity, validate voltage margins, or calibrate sensors-enabling ISO 26262 diagnostic coverage without external references.
Does the LTC3256HMSE#TRPBF require external components to implement its watchdog function?
The LTC3256HMSE#TRPBF supports both internal and external watchdog configurations. With WT tied to OUTCP, it defaults to ~1.6s upper timeout without external components. For adjustable timing, connect a capacitor from WT to GND-e.g., 2.2nF yields ~260ms external reset time. WDI must be actively toggled within the watchdog window; leaving it floating or static asserts RST. No external ICs are needed for basic watchdog operation.
LTC3256HMSE#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) (1)
- Number of Outputs:
- 2
- Frequency - Switching:
- -
- Voltage/Current - Output 1:
- 5V, 100mA
- Voltage/Current - Output 2:
- 3.3V, 250mA
- Voltage/Current - Output 3:
- -
- w/LED Driver:
- No
- w/Supervisor:
- No
- w/Sequencer:
- Yes
- Voltage - Supply:
- 5.5V ~ 38V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-MSOP-EP
LTC3256HMSE#TRPBF FAQ
1.How can I place an order for LTC3256HMSE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3256HMSE#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 LTC3256HMSE#TRPBF reliable?
The price and inventory of LTC3256HMSE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3256HMSE#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3256HMSE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3256HMSE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3256HMSE#TRPBF?
LTC3256HMSE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3256HMSE#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 LTC3256HMSE#TRPBF?
For technical support, including LTC3256HMSE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3256HMSE#TRPBF requirements.
6.How does Aetrix verify that LTC3256HMSE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3256HMSE#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 LTC3256HMSE#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3256HMSE#TRPBF?
All LTC3256HMSE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3256HMSE#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 LTC3256HMSE#TRPBF part is unused and in its original packaging.
Return procedure for LTC3256HMSE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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