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Analog Devices Inc. LT1956IFE-5#PBF
- Part No.:
- LT1956IFE-5#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT1956IFE-5#PBF.pdf
- Description:
- IC REG BUCK 5V 1.5A 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:167
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Product details
Overview
LT1956IFE-5#PBF from Analog Devices (formerly Linear Technology) is a high-voltage, fixed-output 5V synchronous buck switching regulator IC with integrated 1.5A NPN power switch, 500kHz constant-frequency current-mode control, and wide 5.5V–60V input range. It delivers up to 1.5A load current in thermally enhanced 16-pin TSSOP package and is used in industrial power supplies, battery chargers, and distributed power systems requiring robust overvoltage tolerance.
For engineers reviewing the LT1956IFE-5#PBF datasheet, LT1956IFE-5#PBF pinout, LT1956IFE-5#PBF application, or LT1956IFE-5#PBF equivalent, key selection criteria include its fixed 5V output, 0.2Ω switch on-resistance, cycle-by-cycle current limiting, shutdown current of 25µA, and synchronization capability from 580kHz to 700kHz.
Technical Context
The LT1956IFE-5#PBF employs a current-mode architecture with internal slope compensation and patented circuitry that maintains peak switch current across the full duty cycle range-unlike conventional current-mode controllers where limit degrades above 50% duty. Its BOOST pin enables saturation of the on-chip NPN switch via external capacitor/diode, reducing conduction loss to ~0.2Ω equivalent.
It integrates dual shutdown thresholds (0.4V for deep shutdown, 2.38V for UVLO), frequency foldback below 0.8V FB/SENSE voltage, and foldback current limiting below 0.6V SENSE voltage-features critical for short-circuit protection in high-input-voltage applications. The BIAS pin allows efficiency optimization by sourcing bias current from the regulated 5V output when VIN ≫ 5V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.00V ±1.2% (guaranteed over –40°C to 125°C) |
| Input Voltage Range | 5.5V to 60V - supports 48V industrial rails and transient-tolerant battery systems |
| Switch Current Limit | 1.5A minimum peak - maintained across full duty cycle, enabling high step-down ratios |
| Switch On Resistance | 0.2Ω typical - achieved via BOOST-assisted saturation, minimizing conduction loss |
| Switching Frequency | 500kHz ±10% - fixed frequency simplifies EMI filtering; externally synchronizable to 580–700kHz |
| Shutdown Current | 25µA maximum - enables ultra-low-power standby in battery-backed systems |
| SENSE Pin Voltage | 4.94V to 5.06V - precision 5V reference with <±1.2% tolerance at full temperature range |
Pinout & Package
LT1956IFE-5#PBF is housed in a 16-lead plastic TSSOP package with exposed thermal pad (FE package), requiring soldering of the backside pad to PCB ground plane for θJC = 10°C/W thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pins 1, 8, 9, 16) | Power and signal reference ground | Four dedicated GND pins minimize ground impedance; exposed pad must be soldered to PCB ground plane |
| SW (Pin 2) | Switch emitter node | Connects to inductor and catch diode cathode; swings from near-GND to VIN during operation |
| VIN (Pin 4) | Power switch collector supply | Primary input for internal switch and bias circuitry; requires low-inductance input bypass |
| BOOST (Pin 6) | Switch driver boost supply | Driven 5V above VIN via external capacitor/diode to saturate NPN switch and achieve 0.2Ω RON |
| SHDN (Pin 15) | Enable/shutdown control | Logic-compatible input: <0.4V = full shutdown (25µA), >2.38V = UVLO disable, >6V = absolute max |
| SYNC (Pin 14) | External oscillator sync input | Accepts 10–90% duty cycle logic-level signal; locks internal 500kHz oscillator to 580–700kHz range |
| SENSE (Pin 12) | Output voltage sense input | Direct connection to 5V output; internal divider eliminates external resistors; enables foldback protection |
| VC (Pin 11) | Error amplifier output / current limit setpoint | Used for loop compensation; clamped between 0.9V and 2.1V; drives current into external RC network |
| BIAS (Pin 10) | Efficiency-optimized bias supply | When tied to 5V output, shifts internal bias current from VIN to VOUT, improving efficiency at high VIN/VOUT ratios |
Key Features
| Feature | Design Value |
|---|---|
| Patented duty-cycle-independent current limit | Maintains 1.5A peak switch current up to 90% duty cycle-enables stable regulation at VOUT/VIN = 5V/60V (8.3%) without current foldback |
| Integrated BOOST drive architecture | Reduces effective switch RON to 0.2Ω using external capacitor/diode, eliminating need for external gate driver or MOSFET |
| Dual-threshold SHDN pin | Provides precise undervoltage lockout (2.38V) and micropower shutdown (0.4V), supporting sequenced power-up and battery cutoff |
| Automatic frequency & current foldback | Reduces switching frequency and peak current when SENSE < 0.8V or < 0.6V-limits power dissipation during startup or short-circuit faults |
| BIAS pin efficiency enhancement | When connected to 5V output, reduces total input-referred quiescent current to 2.4mA (VIN=15V), increasing light-load efficiency by up to 8% |
Applications
| Industrial Power Supplies | Battery Chargers |
|---|---|
Use Scenario: Converting 24V or 48V DC distribution bus to regulated 5V for PLC I/O modules and sensor interfaces. IC Role / Device Role / Timing Role: Primary non-isolated buck regulator delivering 1.5A at 5V with transient immunity to 60V line surges. Use Value: Wide 5.5–60V input range and 60V absolute max VIN rating eliminate need for upstream TVS or pre-regulator in harsh industrial environments. |
Use Scenario: Charging lead-acid or LiFePO4 batteries from variable solar or vehicle alternator sources. IC Role / Device Role / Timing Role: Constant-voltage stage regulator maintaining precise 5.00V ±1.2% for USB-powered charging circuits or microcontroller supervision. Use Value: Fixed 5V output with tight tolerance and built-in foldback protection prevents overvoltage damage during battery disconnect transients. |
| Distributed Power Systems | Automotive Aftermarket Electronics |
Use Scenario: Point-of-load conversion in telecom shelf systems where 48V backplane powers multiple 5V subsystems. IC Role / Device Role / Timing Role: High-efficiency, thermally robust buck converter operating continuously at 125°C junction temperature. Use Value: Exposed-pad TSSOP package (θJC = 10°C/W) and –40°C to 125°C guaranteed operation enable reliable deployment in confined, unventilated enclosures. |
Use Scenario: Powering dashcams, GPS trackers, or telematics units directly from vehicle battery (9–16V nominal, up to 60V load dump). IC Role / Device Role / Timing Role: Input-transient-hardened 5V regulator with UVLO (2.38V) and shutdown (0.4V) for cold-cranking and battery-dead detection. Use Value: Dual SHDN thresholds ensure clean power sequencing during engine start/stop cycles and prevent brownout-induced MCU resets. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar fixed-output buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3642EMSE-5#PBF | 40V max input, 2A switch, 3mm × 4mm MSOP; no BOOST pin; uses MOSFET switch | Lower input voltage ceiling; higher current capability; no external BOOST capacitor required | Preferred for space-constrained designs with VIN ≤ 40V and need for >1.5A output |
| LM5164QPWPRQ1 | 65V max input, 1A switch, integrated MOSFET; requires external compensation; no fixed 5V variant | Automotive AEC-Q100 qualified; needs external resistor divider for 5V; lower current rating | Chosen when automotive qualification, extended temperature, or higher VIN margin (>60V) is mandatory |
Compared with LTC3642EMSE-5#PBF and LM5164QPWPRQ1, LT1956IFE-5#PBF uniquely combines 60V input rating, fixed 5V output, 1.5A current, and BOOST-enabled bipolar switch in a single TSSOP package-making it optimal for cost-sensitive, high-VIN industrial converters where layout simplicity and proven surge resilience are prioritized over footprint size or AEC-Q100 compliance.
Availability
LT1956IFE-5#PBF is available at Aetrix Electronics and suitable for industrial power supplies, battery chargers, and distributed power systems requiring stable component supply, long-term lifecycle support, and guaranteed parametric performance across –40°C to 125°C.
Supply support for LT1956IFE-5#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 acquired Linear Technology in 2017 and maintains full product support, datasheets, and application engineering for legacy Linear parts including the LT1956 family.
The LT1956 series was designed as high-input-voltage monolithic buck regulators targeting industrial, automotive, and telecom power systems where reliability under voltage transients and wide input range are essential.
FAQ
What is the maximum input voltage rating for the LT1956IFE-5#PBF?
The LT1956IFE-5#PBF has an absolute maximum input voltage (VIN) rating of 60V, with guaranteed operation from 5.5V to 60V. This makes it suitable for 48V industrial buses and automotive load-dump tolerant applications. Exceeding 60V risks permanent damage, even momentarily.
Does the LT1956IFE-5#PBF require external feedback resistors to set the output voltage?
No. The LT1956IFE-5#PBF features an internal resistor divider that fixes the output to 5.00V, and Pin 12 functions as a SENSE input directly connected to the output. External resistors are unnecessary-unlike the adjustable LT1956 version which uses Pin 12 as FB with external dividers.
How does the BOOST pin function in the LT1956IFE-5#PBF?
The BOOST pin on the LT1956IFE-5#PBF accepts a voltage ~5V above VIN (via external capacitor and diode) to drive the base of the internal NPN power switch, forcing deep saturation and achieving an effective on-resistance of 0.2Ω. Without BOOST, switch losses would increase significantly, reducing efficiency and thermal margin.
What protection features does the LT1956IFE-5#PBF include during output short-circuit conditions?
The LT1956IFE-5#PBF implements dual-foldback protection: when SENSE voltage drops below 0.8V, switching frequency reduces ~5:1; below 0.6V, peak switch current folds back from 1.5A to <1A. These actions-combined with 25µA shutdown current-limit power dissipation and prevent thermal runaway during sustained shorts.
Can the LT1956IFE-5#PBF be synchronized to an external clock?
Yes. The SYNC pin (Pin 14) accepts logic-level signals with 10–90% duty cycle and synchronizes the internal 500kHz oscillator across a 580kHz–700kHz range. When unused, SYNC must be tied to GND to prevent noise coupling and erratic operation.
LT1956IFE-5#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 5.5V
- Voltage - Input (Max):
- 60V
- Voltage - Output (Min/Fixed):
- 5V
- Voltage - Output (Max):
- -
- Current - Output:
- 1.5A (Switch)
- Frequency - Switching:
- 500kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP-EP
LT1956IFE-5#PBF FAQ
1.How can I place an order for LT1956IFE-5#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1956IFE-5#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 LT1956IFE-5#PBF reliable?
The price and inventory of LT1956IFE-5#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1956IFE-5#PBF is usually 5 days.
3.What payment methods are accepted for LT1956IFE-5#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1956IFE-5#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1956IFE-5#PBF?
LT1956IFE-5#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1956IFE-5#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 LT1956IFE-5#PBF?
For technical support, including LT1956IFE-5#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1956IFE-5#PBF requirements.
6.How does Aetrix verify that LT1956IFE-5#PBF is sourced from the original manufacturer or authorized distributors?
All LT1956IFE-5#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 LT1956IFE-5#PBF meets industry standards.
7.What is the process for return or replacement of LT1956IFE-5#PBF?
All LT1956IFE-5#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1956IFE-5#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 LT1956IFE-5#PBF part is unused and in its original packaging.
Return procedure for LT1956IFE-5#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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