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Analog Devices Inc. LT1956EGN#TRPBF
- Part No.:
- LT1956EGN#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
LT1956EGN#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 1.5A 16SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,420
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Product details
Overview
LT1956EGN#TRPBF from Analog Devices (formerly Linear Technology) is a high-voltage, current-mode 500kHz monolithic buck switching regulator with 5.5V–60V input range, 1.5A peak switch current, and 0.2Ω on-resistance. It integrates a high-efficiency NPN power switch, oscillator, error amplifier, and cycle-by-cycle current limiting-designed for industrial power conversion where wide VIN and robust short-circuit protection are required.
For engineers reviewing the LT1956EGN#TRPBF datasheet, LT1956EGN#TRPBF pinout, LT1956EGN#TRPBF application, or LT1956EGN#TRPBF equivalent, key selection criteria include its fixed 1.219V feedback reference (not 5V), guaranteed 1.5A peak switch current across full duty cycle, thermally enhanced 16-pin SSOP package with four ground pins, and frequency foldback behavior below 0.8V FB voltage during startup or overload.
Technical Context
The LT1956EGN#TRPBF employs a current-mode architecture with an internal 500kHz oscillator, slope compensation cancellation circuitry (U.S. Patent No. 6,498,466), and dual-threshold shutdown comparator (2.38V UVLO / 0.4V deep shutdown). Its BOOST pin enables saturation of the integrated NPN switch via external capacitor-diode charge pump, reducing conduction loss to ~0.2Ω equivalent.
It features patented peak switch current maintenance over full duty cycle (0–90%), cycle-by-cycle current limiting, and FB pin–driven frequency foldback (down to ~100kHz) and current limit reduction when FB < 0.8V or < 0.6V-critical for safe short-circuit operation at high VIN without thermal runaway.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 5.5V to 60V - supports 24V/48V industrial rails and automotive transients up to 60V. |
| Switch Current Limit | 1.5A (min), maintained across 0–90% duty cycle - enables stable operation at high step-down ratios without current derating. |
| Switch On Resistance | 0.2Ω (typ) - achieved via BOOST-assisted saturation, enabling low conduction loss comparable to MOSFET-based regulators. |
| Feedback Reference | 1.219V (±1.2%) - precise internal reference for adjustable output; not 5V (LT1956-5 variant only has fixed 5V). |
| Switching Frequency | 500kHz (±10%) - fixed-frequency operation simplifies EMI filtering; synchronizable from 580kHz to 700kHz via SYNC pin. |
| Shutdown Current | 25µA (max) - ultra-low quiescent draw in shutdown, suitable for battery-backed systems. |
| Operating Temp Range | –40°C to 125°C - qualified for industrial and automotive under-hood environments. |
Pinout & Package
LT1956EGN#TRPBF is housed in a 16-lead plastic SSOP package (GN grade) with exposed ground plane connection via pins 1, 8, 9, and 16. The fused-lead construction improves thermal performance (θJA = 85°C/W) and mechanical reliability in high-vibration environments.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (1, 8, 9, 16) | Power and signal ground reference | Four dedicated ground pins minimize ground bounce and improve load regulation; must be tied to low-impedance PCB ground plane. |
| SW (2) | Emitter of internal NPN power switch | Drives external catch diode and inductor; swings from –0.8V (clamped) to VIN; requires low-inductance layout. |
| VIN (4) | Collector of internal NPN switch & bias source | Powers control circuitry when BIAS pin is unconnected; subject to high dI/dt - demands local 10µF+ ceramic bypass. |
| BOOST (6) | Charge-pump drive for switch saturation | Must be connected to SW via 100V ceramic capacitor + Schottky diode; enables 0.2Ω RCE(sat) equivalent. |
| BIAS (10) | Efficiency-boosting auxiliary supply input | When tied to VOUT ≥ 3V, shifts internal bias current from VIN to VOUT - improves efficiency at high VIN/light loads. |
| FB (12) | Feedback input for adjustable output | Accepts 1.219V reference; connects to resistor divider from VOUT; enables frequency/current foldback below 0.8V/0.6V. |
| VC (11) | Error amplifier output & current limit setpoint | Used for loop compensation; clamps at ~2.1V; can override current limit or disable switching if driven to GND. |
| SHDN (15) | Enable/disable control with dual thresholds | 2.38V = UVLO start-up threshold; 0.4V = deep shutdown; open-circuit defaults to enabled via internal bias. |
| SYNC (14) | External clock synchronization input | Logic-compatible (1.5–2.2V min amplitude); accepts 580–700kHz square wave; tie to GND if unused. |
Key Features
| Feature | Design Value |
|---|---|
| Patented duty-cycle–independent current limit | Maintains 1.5A peak switch current from 0% to 90% duty cycle - eliminates need for slope compensation derating in high-VIN applications. |
| Integrated BOOST-driven NPN switch | 0.2Ω effective on-resistance achieved without external gate driver - reduces die size vs. MOSFET while retaining low conduction loss. |
| FB pin–activated protection suite | Automatically reduces switching frequency (<0.8V FB) and current limit (<0.6V FB) during startup or short-circuit - prevents thermal runaway without external circuitry. |
| Thermally enhanced SSOP package | Four ground pins and fused-lead construction deliver θJA = 85°C/W - enables 1.5A continuous operation without heatsink at 25°C ambient. |
| Wide-input, high-temp industrial qualification | Specified from –40°C to 125°C junction; absolute max VIN = 60V, BOOST = 68V - suitable for 48V telecom, railway, and off-highway equipment. |
Applications
| Industrial Power Supply | Automotive Subsystem |
|---|---|
Use Scenario: 48V rail conversion to 5V/3.3V for PLC I/O modules and sensor interfaces in factory automation cabinets. IC Role / Device Role / Timing Role: Primary buck regulator delivering regulated 5V from fluctuating 36–57V DC input; handles load dumps and cold-crank transients. Use Value: 60V absolute max input and 125°C operation ensure uninterrupted function during brownouts and ambient temperature spikes in enclosed enclosures. | Use Scenario: Powering infotainment head-unit microcontrollers and CAN transceivers from vehicle battery (9–16V nominal, up to 60V during load dump). IC Role / Device Role / Timing Role: High-reliability step-down converter with UVLO (2.38V SHDN threshold) and foldback protection against reverse-battery and short-circuit faults. Use Value: Dual-threshold shutdown prevents false turn-on during cranking; frequency foldback limits power dissipation during sustained shorts. |
| Battery Charger Front-End | Distributed Telecom Power |
Use Scenario: Intermediate stage in multi-cell Li-ion charger converting 24V adapter output to 12.6V for CC/CV charging circuitry. IC Role / Device Role / Timing Role: Constant-frequency buck controller regulating mid-rail voltage; interfaces with analog front-end and battery management IC. Use Value: 500kHz fixed frequency enables compact LC filter design; BIAS pin connection to 12.6V output improves efficiency by >3% vs. VIN-powered bias. | Use Scenario: Point-of-load conversion in 48V telecom shelf, powering FPGA I/O banks and SerDes supplies requiring tight regulation and fast transient response. IC Role / Device Role / Timing Role: Current-mode buck regulator providing 1.8V/3.3V outputs; synchronized to system clock via SYNC pin to reduce beat-frequency noise. Use Value: Cycle-by-cycle current limiting and 1.5A peak current support rapid load steps up to 1A without output droop or instability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-voltage buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3632EMSE#PBF | 40V max VIN, 1.2A switch, integrated MOSFET, 3mm × 4mm MSOP; no BOOST pin or duty-cycle–independent current limit. | Suitable for lower-input, space-constrained designs; lacks 60V capability and industrial temp range. | Select LTC3632EMSE#PBF only if VIN ≤ 40V and board area is critical; LT1956EGN#TRPBF remains preferred for 48V+ systems. |
| LM5164QPWPRQ1 | 65V max VIN, 1A switch, integrated MOSFET, automotive AEC-Q100 Grade 1; uses external compensation, no FB-foldback. | Qualified for automotive use but rated only to 125°C junction (same as LT1956EGN#TRPBF); lower peak current limits short-circuit robustness. | Choose LM5164QPWPRQ1 for automotive production with AEC-Q100 compliance; LT1956EGN#TRPBF offers superior 1.5A fault current handling and foldback safety. |
Compared with LTC3632EMSE#PBF and LM5164QPWPRQ1, the LT1956EGN#TRPBF uniquely combines 60V input, 1.5A duty-cycle–invariant current limit, and FB-triggered foldback - making it the only option among the three capable of surviving sustained 60V input with dead-short output without thermal shutdown.
Availability
LT1956EGN#TRPBF is available at Aetrix Electronics and suitable for industrial power supplies, automotive subsystems, and distributed telecom power systems requiring stable component supply across extended temperature and high-input-voltage conditions.
Supply support for LT1956EGN#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.
The LT1956EGN#TRPBF belongs to Linear's legacy high-voltage monolithic buck regulator family, engineered specifically for rugged industrial and transportation applications demanding wide input range, fault resilience, and long-term supply stability.
FAQ
What is the key functional difference between LT1956EGN#TRPBF and LT1956EGN-5#TRPBF?
The LT1956EGN#TRPBF features an adjustable output using a 1.219V feedback reference, requiring external resistor divider to set VOUT. In contrast, the LT1956EGN-5#TRPBF has a fixed 5V output with internal divider; its FB pin functions as a SENSE pin directly connected to VOUT. Pin compatibility and package are identical, but feedback network design and application scope differ fundamentally.
Does LT1956EGN#TRPBF require an external BOOST capacitor and diode?
Yes, the LT1956EGN#TRPBF requires an external BOOST capacitor (typically 100V ceramic) and Schottky diode (e.g., MMSD914) connected between BOOST and SW pins. This charge-pump network generates the elevated gate drive voltage needed to saturate the internal NPN switch and achieve its specified 0.2Ω on-resistance - omission causes excessive conduction loss and thermal failure.
Can LT1956EGN#TRPBF operate with input voltage below 5.5V?
No - the absolute minimum input voltage for reliable operation of LT1956EGN#TRPBF is 5.5V, as guaranteed by internal bias line regulation. Attempting to operate below this threshold risks oscillator stall, reference drift, or undefined shutdown behavior. Note that "minimum input to run" rises with output voltage and load; e.g., 5V output requires ≥7.5V VIN at full load per typical curves.
How does the FB pin foldback protection work in LT1956EGN#TRPBF?
In LT1956EGN#TRPBF, when FB voltage drops below 0.8V (e.g., during startup or short-circuit), internal circuitry draws current from the FB pin to reduce switching frequency (~5:1 foldback). Below 0.6V, it also clamps VC to lower the current limit threshold. These actions jointly limit power dissipation in the IC, external diode, and inductor - verified in typical performance graphs G01, G09, and G10.
Is LT1956EGN#TRPBF pin-compatible with newer Analog Devices buck regulators?
No - LT1956EGN#TRPBF uses a proprietary 16-pin SSOP pinout optimized for its BOOST/NPN architecture and dual-threshold SHDN functionality. Modern Analog Devices parts like LTC3632 or LT86xx series use different pin assignments, integrated MOSFETs, and control schemes. Direct replacement requires PCB redesign; migration should be based on functional requirements, not pin count or package footprint.
LT1956EGN#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 5.5V
- Voltage - Input (Max):
- 60V
- Voltage - Output (Min/Fixed):
- 1.219V
- Voltage - Output (Max):
- 54V
- Current - Output:
- 1.5A (Switch)
- Frequency - Switching:
- 500kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SSOP
LT1956EGN#TRPBF FAQ
1.How can I place an order for LT1956EGN#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1956EGN#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 LT1956EGN#TRPBF reliable?
The price and inventory of LT1956EGN#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1956EGN#TRPBF is usually 5 days.
3.What payment methods are accepted for LT1956EGN#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1956EGN#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1956EGN#TRPBF?
LT1956EGN#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1956EGN#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 LT1956EGN#TRPBF?
For technical support, including LT1956EGN#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1956EGN#TRPBF requirements.
6.How does Aetrix verify that LT1956EGN#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT1956EGN#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 LT1956EGN#TRPBF meets industry standards.
7.What is the process for return or replacement of LT1956EGN#TRPBF?
All LT1956EGN#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1956EGN#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 LT1956EGN#TRPBF part is unused and in its original packaging.
Return procedure for LT1956EGN#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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