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Analog Devices Inc. LT1950IGN#TRPBF
- Part No.:
- LT1950IGN#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
LT1950IGN#TRPBF.pdf
- Description:
- IC REG CTRLR MULT TOP 16SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,615
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Product details
Overview
LT1950IGN#TRPBF from Analog Devices (formerly Linear Technology) is a wide-input, current-mode PWM controller for forward, flyback, boost, and SEPIC DC/DC converters, driving external N-channel MOSFETs. It features programmable 100–500 kHz switching frequency, 60 ns current-sense delay, ±2% 1.23 V FB reference, 2.5 V auxiliary reference output, and integrated auxiliary boost converter enabling 10 V gate drive from as low as 3 V input - used in telecom power supplies delivering 26 V/5 A.
For engineers reviewing the LT1950IGN#TRPBF datasheet, LT1950IGN#TRPBF pinout, LT1950IGN#TRPBF application, or LT1950IGN#TRPBF equivalent, key selection considerations include volt-second clamp programming via VSEC, slope compensation adjustability, shutdown hysteresis configuration, and VIN2 supply architecture for low-input-voltage gate drive integrity.
Technical Context
The LT1950IGN#TRPBF implements true current-mode control with externally adjustable slope compensation to prevent subharmonic oscillation above 50% duty cycle. Its fast 60 ns current-sense comparator enables precise peak-current limiting, while the error amplifier operates as a full op amp supporting flexible RC compensation networks between COMP and FB pins.
It integrates an auxiliary boost switcher (125 mA limit, 0.5 µs fixed off-time) on the BOOST pin to generate regulated ~11 V at VIN2 from inputs as low as 3 V, enabling robust gate drive for standard-level N-MOSFETs. The VSEC pin programs maximum duty cycle as (105/VSEC)% over 1.4–2.8 V, providing critical volt-second clamping for forward converter transformer reset.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3 V to 25 V - supports wide-range industrial, automotive, and telecom inputs without pre-regulation |
| Switching Frequency | 100 kHz to 500 kHz - set by single ROSC resistor; enables optimization of size vs. efficiency trade-offs |
| FB Reference Voltage | 1.23 V ±2% - high-accuracy feedback threshold enabling tight output voltage regulation |
| Current Sense Delay | 60 ns - minimizes propagation delay in peak-current loop, improving transient response and stability |
| VREF Output | 2.500 V ±0.075 V - stable, 2.5 mA-capable reference for external circuitry or biasing |
| Shutdown Threshold | 1.32 V ±0.06 V - precise UVLO trigger with programmable hysteresis via SHDN pin current |
| Max Duty Cycle Clamp | 63–87% - programmable via VSEC pin voltage for safe forward converter operation |
| GATE Drive Capability | 10 V min at VIN ≥ 3 V - enabled by internal boost converter, ensuring reliable N-MOSFET turn-on |
Pinout & Package
LT1950IGN#TRPBF is housed in a 16-lead narrow plastic SSOP package (GN), with 0.65 mm lead pitch and exposed pad thermal design. Pin 8 is analog ground (GND); Pin 13 is power ground (PGND) for gate driver stage; thermal resistance θJA = 110°C/W, θJC = 30°C/W (pin 8).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| COMP (1) | Error amplifier output | Drives current sense threshold; connects to RC network for loop compensation |
| FB (2) | Inverting input to error amplifier | Compares output divider voltage to 1.23 V reference; sets regulated output voltage |
| ROSC (3) | Oscillator frequency programming | Resistor to GND sets fOSC from 100–500 kHz; nominal pin voltage = 1 V |
| SYNC (4) | External clock synchronization input | Accepts logic-level signal up to 1.5×fOSC; enables system-wide clock alignment |
| SLOPE (5) | Slope compensation adjustment | Open = default; resistor to VREF increases compensation for >50% duty cycles |
| VREF (6) | 2.5 V reference output | Sources up to 2.5 mA; requires 0.1 µF ceramic bypass to GND |
| SHDN (7) | Shutdown control input | 1.32 V threshold with programmable hysteresis; pulls device into 5 µA shutdown state |
| GND (8) | Analog ground reference | Reference point for FB, ROSC, VREF bypass, and sensitive analog circuitry |
| BLANK (9) | Leading edge blanking control | Resistor to GND extends blanking time from 110 ns to 290 ns to suppress turn-on noise |
| ISENSE (10) | Current sense comparator input | Monitors MOSFET source resistor; trip threshold = COMP voltage, max 100 mV |
| VIN2 (11) | Gate driver supply input | Must exceed 8 V to enable GATE output; can be boosted from VIN ≥ 3 V via BOOST pin |
| GATE (12) | High-current MOSFET gate driver output | Drives N-MOSFET gate with 10–13 V swing; clamped to 13 V when VIN2 > 12 V |
| PGND (13) | Power ground for gate driver | Separate return path for high di/dt gate current; must be routed to minimize noise coupling |
| BOOST (14) | Internal boost switch collector | Drives external inductor/diode/capacitor to generate ~11 V at VIN2 from low VIN |
| VIN (15) | Main IC supply input | Bypassed locally; powers internal circuitry; UVLO = 2.6 V; functional down to 3 V with BOOST active |
| VSEC (16) | Volt-second clamp programming | Programs max duty cycle as (105/VSEC)% for forward converter safety; tie to GND if unused |
Key Features
| Feature | Design Value |
|---|---|
| Wide input range operation | 3 V to 25 V input enables direct battery or unregulated rail use without pre-buck stage |
| Integrated auxiliary boost converter | Generates 10–11 V gate drive from VIN ≥ 3 V, supporting standard N-MOSFETs at low input |
| Programmable volt-second clamp | VSEC pin sets (105/VSEC)% max duty cycle - essential for transformer reset in forward topologies |
| Adjustable slope compensation | External resistor from SLOPE to VREF scales compensation to match inductor and fOSC choice |
| Fast 60 ns current sense path | Minimizes delay in current-mode loop, improving stability margin and load transient response |
| Accurate shutdown with hysteresis | 1.32 V SHDN threshold + programmable µA-level hysteresis enables precise, noise-immune UVLO |
Applications
| Telecom Power Supplies | Automotive Power Supplies |
|---|---|
Use Scenario: 36–72 V DC input converted to isolated 26 V/5 A output in base station power modules. IC Role / Device Role / Timing Role: Primary-side PWM controller managing forward converter topology with volt-second clamp via VSEC pin. Use Value: Enables transformer reset protection and stable operation across wide input range without auxiliary winding. |
Use Scenario: 12 V battery input stepped up to 24 V for ADAS camera or radar subsystems in start-stop vehicles. IC Role / Device Role / Timing Role: Boost controller with programmable frequency and leading-edge blanking for EMI-sensitive environments. Use Value: 60 ns current sense delay and adjustable blanking ensure reliable current limiting during cold-crank transients. |
| Isolated DC/DC Converters | Portable Electronic Equipment |
Use Scenario: Flyback-based medical-grade isolated 5 V/2 A supply meeting IEC 60601 creepage requirements. IC Role / Device Role / Timing Role: Current-mode flyback controller with slope compensation and SYNC capability for noise reduction. Use Value: External slope adjustability avoids subharmonic oscillation across variable line/load conditions. |
Use Scenario: Compact 24 V-to-5 V nonisolated buck-boost converter in portable test equipment with 3 V minimum battery input. IC Role / Device Role / Timing Role: SEPIC controller leveraging BOOST pin to sustain 10 V gate drive during battery discharge. Use Value: Maintains MOSFET RDS(ON) performance and efficiency down to 3 V input without external LDO. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PWM controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3748IMS#TRPBF | Primary-side flyback controller with integrated MOSFET driver; no BOOST pin or VSEC clamp; 5 V VREF only | Designed specifically for flyback with opto-couplerless regulation; lacks forward/SEPIC support | Select when flyback isolation is required and gate drive boosting is unnecessary |
| UCC28064DR | Fixed-frequency current-mode controller; no integrated boost; 1.25 V FB reference; 500 kHz max fOSC; SOIC-16 | Requires external gate driver supply ≥ 10 V; no VIN2 boost capability limits <8 V operation | Select for cost-sensitive designs with stable ≥8 V input and no low-VIN gate drive requirement |
Compared with LT1950IGN#TRPBF, LT3748IMS#TRPBF offers tighter flyback regulation but omits volt-second clamping and low-VIN boosting, while UCC28064DR provides similar frequency range but lacks the integrated auxiliary boost converter essential for 3–8 V input operation.
Availability
LT1950IGN#TRPBF is available at Aetrix Electronics and suitable for telecom power supplies, automotive DC/DC converters, and isolated medical power systems requiring stable component supply, long-term lifecycle support, and guaranteed −40°C to +125°C operation.
Supply support for LT1950IGN#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. (including legacy Linear Technology products) is a global leader in high-performance analog, mixed-signal, and power management semiconductors for precision signal chain and power applications.
The LT1950IGN#TRPBF belongs to Linear's high-voltage current-mode PWM controller product line, designed for rugged, wide-input DC/DC conversion in telecom infrastructure, industrial power, and transportation systems where reliability under voltage transients is critical.
FAQ
What is the minimum input voltage required for LT1950IGN#TRPBF to operate with full functionality?
The LT1950IGN#TRPBF achieves full functionality-including 10 V gate drive-down to 3 V input when the BOOST pin is used to generate VIN2. Without BOOST, VIN2 must be supplied externally ≥8 V, raising the effective minimum input to 8 V. Internal undervoltage lockout activates below 2.6 V on VIN, and the 2.5 V VREF becomes active only after both VIN > 2.6 V and VIN2 > 6.8 V. This dual-threshold behavior ensures controlled startup and fault-safe disable.
How does the VSEC pin function in LT1950IGN#TRPBF, and what happens if it is left unconnected?
The VSEC pin on the LT1950IGN#TRPBF programs maximum duty cycle as (105/VSEC)% for VSEC between 1.4 V and 2.8 V, providing critical volt-second clamping in forward converters. If left unconnected, VSEC floats near 0 V, disabling the clamp and allowing natural duty cycle up to ~95%. To ensure safe default operation, the datasheet specifies that VSEC must be tied to GND if unused - otherwise unpredictable behavior may occur due to leakage currents affecting the internal comparator.
Can LT1950IGN#TRPBF synchronize to an external clock, and what are the frequency limits?
Yes, the LT1950IGN#TRPBF supports synchronization via its SYNC pin, accepting logic-level signals with 10–90% duty cycle. The maximum allowable SYNC frequency is 1.5 × fOSC, where fOSC is the free-running oscillator frequency set by ROSC. For example, with ROSC = 249 kΩ (fOSC ≈ 200 kHz), SYNC must not exceed 300 kHz. Exceeding this limit risks loss of slope compensation and potential instability, as the internal ramp generator may not align properly with the external clock edge.
What is the purpose of the BLANK pin on LT1950IGN#TRPBF, and how is blanking time adjusted?
The BLANK pin on the LT1950IGN#TRPBF controls leading-edge blanking duration to suppress noise during MOSFET turn-on. With BLANK shorted to GND, blanking is ~110 ns; inserting a resistor (e.g., 75 kΩ) between BLANK and GND extends it to ~290 ns. Blank time is independent of switching frequency and remains fixed per configuration. Fault conditions exceeding 125 mV at ISENSE override blanking, reducing the ISENSE-to-GATE delay to 60 ns for fast overcurrent protection - a critical safety feature confirmed in the Electrical Characteristics table.
Does LT1950IGN#TRPBF support both isolated and non-isolated topologies, and which ones are explicitly validated?
Yes, the LT1950IGN#TRPBF is explicitly validated for forward, flyback, boost, and SEPIC topologies - covering both isolated (forward, flyback) and non-isolated (boost, SEPIC) configurations. The datasheet includes complete reference designs for 36–72 V to 26 V/5 A forward converters and 3–25 V to 5 V SEPIC supplies. Its current-mode architecture, programmable slope compensation, and VSEC-based volt-second clamp make it uniquely suited for forward converters, while the BOOST pin enables robust operation in low-input non-isolated applications where gate drive voltage is critical.
LT1950IGN#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
- Output Type:
- Transistor Driver
- Function:
- Step-Up, Step-Up/Step-Down
- Output Configuration:
- Positive, Isolation Capable
- Topology:
- Boost, Flyback, Forward Converter, SEPIC
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 3V ~ 25V
- Frequency - Switching:
- 100kHz ~ 500kHz
- Duty Cycle (Max):
- 95%
- Synchronous Rectifier:
- No
- Clock Sync:
- Yes
- Serial Interfaces:
- -
- Control Features:
- Enable, Frequency Control
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SSOP
LT1950IGN#TRPBF FAQ
1.How can I place an order for LT1950IGN#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1950IGN#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 LT1950IGN#TRPBF reliable?
The price and inventory of LT1950IGN#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1950IGN#TRPBF is usually 5 days.
3.What payment methods are accepted for LT1950IGN#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1950IGN#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1950IGN#TRPBF?
LT1950IGN#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1950IGN#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 LT1950IGN#TRPBF?
For technical support, including LT1950IGN#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1950IGN#TRPBF requirements.
6.How does Aetrix verify that LT1950IGN#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT1950IGN#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 LT1950IGN#TRPBF meets industry standards.
7.What is the process for return or replacement of LT1950IGN#TRPBF?
All LT1950IGN#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1950IGN#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 LT1950IGN#TRPBF part is unused and in its original packaging.
Return procedure for LT1950IGN#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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