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Analog Devices Inc. LT1952IGN#TRPBF
- Part No.:
- LT1952IGN#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
LT1952IGN#TRPBF.pdf
- Description:
- IC REG CTRLR FWRD CONV 16SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,753
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Product details
Overview
LT1952IGN#TRPBF from Analog Devices (formerly Linear Technology) is a current-mode PWM controller optimized for single-switch synchronous forward converters. It delivers synchronous rectifier control, programmable volt-second clamp (preventing transformer saturation), and precision 107mV overcurrent detection with hiccup protection. Designed for 36V–72V input telecom bus converters delivering 12V/20A semi-regulated output, it supports 100kHz–500kHz switching and operates in –40°C to 125°C industrial temperature range.
For engineers reviewing the LT1952IGN#TRPBF datasheet, LT1952IGN#TRPBF pinout, LT1952IGN#TRPBF application, or LT1952IGN#TRPBF equivalent, key selection criteria include its adaptive duty-cycle clamp for >50% operation, low 460µA startup current from high VIN, true op-amp COMP pin for flexible compensation, and dual gate drivers (OUT ±1A, SOUT ±50mA) with programmable timing delay for synchronous rectifier optimization.
Technical Context
The LT1952IGN#TRPBF implements current-mode control with an internal 1.23V FB reference and true op-amp error amplifier (COMP), enabling wide-range compensation networks. Its adaptive volt-second clamp uses SD_VSEC and SS_MAXDC pins-resistively derived from input voltage-to dynamically limit maximum duty cycle and prevent transformer saturation during line/load transients.
It features two independent gate drivers: OUT (±1A, 13V-clamped) for primary-side N-MOSFET, and SOUT (±50mA, 12V-clamped) for secondary-side synchronous rectifiers, with programmable tDELAY (via DELAY pin resistor) to align turn-on timing. Leading edge blanking (BLANK pin) and slope compensation (ISENSE series resistor) are fully adjustable for stability across diverse MOSFETs and inductors.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology | Current-mode synchronous forward controller with single-primary-MOSFET support |
| Input Voltage Range | 36V to 72V system input; VIN supply range 0V to 25V (with external clamp if >25V) |
| Switching Frequency | Programmable 100kHz–500kHz via ROSC resistor; synchronizable up to 1.5×fOSC |
| Overcurrent Threshold | Precision 107mV at OC pin-duty-cycle-independent for reliable short-circuit protection |
| Startup Current | 460µA typical at VIN ON = 14.25V-enables micropower bootstrap start-up from high-input rails |
| Operating Temperature | –40°C to +125°C junction (I-grade); validated for industrial telecom power supplies |
| Package | 16-pin SSOP (GN package), 6.2mm × 5.3mm footprint, 1.0mm max height |
Pinout & Package
LT1952IGN#TRPBF is housed in a 16-lead plastic SSOP (GN) package with exposed pad for thermal performance. Pin numbering follows standard top-view orientation (Pin 1 = COMP, Pin 16 = SOUT).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| COMP (1) | Error amplifier output | True op-amp output (0.8V–2.5V range) commanding peak current; enables opto-coupled or direct compensation |
| FB (2) | Feedback input | Compares output voltage (via resistor divider) against 1.23V internal reference; FB = VREF disables amplifier |
| ROSC (3) | Oscillator programming | Resistor-to-ground sets fOSC (100–500kHz); nominal pin voltage = 1.0V |
| SYNC (4) | External clock input | Logic-compatible sync input (10–90% duty); unused pin may be left open or grounded |
| SS_MAXDC (5) | Soft-start & max duty control | Voltage-programmed clamp for adaptive duty cycle; capacitor + resistor divider sets soft-start ramp time |
| VREF (6) | Internal reference output | 2.5V ±2.5% reference, capable of sourcing 2.5mA; requires 0.1µF ceramic bypass |
| SD_VSEC (7) | Volt-second clamp & UVLO | 1.32V threshold for shutdown and transformer reset safeguard; 10µA hysteresis enables programmable UVLO |
| GND (8) | Analog ground | Reference for FB, COMP, and internal analog circuitry; separate from PGND |
| BLANK (9) | Leading edge blanking control | Resistor-to-ground adjusts blanking duration (180–540ns) to suppress MOSFET switching noise |
| ISENSE (10) | Primary current sense input | Connects to source of primary MOSFET; series resistor programs slope compensation |
| OC (11) | Overcurrent detection | Dedicated 107mV threshold pin-triggers hiccup-mode soft-start on fault |
| DELAY (12) | Synchronous timing delay | Resistor-to-ground programs tDELAY (40–120ns) between SOUT and OUT rising edges |
| PGND (13) | Power ground | Return path for OUT/SOUT drivers and high-current internal circuits |
| OUT (14) | Primary MOSFET gate driver | ±1A peak drive, 13V clamped; active pull-off in shutdown prevents shoot-through |
| VIN (15) | Supply input | Operates from 0–25V; undervoltage lockout at 14.25V ON / 8.75V OFF (I-grade) |
| SOUT (16) | Synchronous rectifier sync signal | ±50mA peak, 12V clamped; phase-aligned with OUT for secondary-side FET timing |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectifier control | Dual-output architecture (OUT + SOUT) with programmable tDELAY enables precise timing for high-efficiency secondary-side synchronous rectification |
| Adaptive volt-second clamp | SD_VSEC/SS_MAXDC interface eliminates need for external timing capacitor and reduces oscillator dependency-improves transformer reset accuracy by >5× vs fixed-clamp designs |
| Low-stress hiccup protection | 107mV OC threshold + soft-start latch ensures immediate shutdown and controlled restart during overcurrent-reduces thermal stress on MOSFET and transformer |
| Micropower bootstrap start-up | 460µA VIN start-up current allows RC-based bias supply from high-voltage rail-eliminates auxiliary winding during startup |
| Flexible loop compensation | True op-amp COMP pin supports Type II/III networks and opto-coupler interfaces-enables stable regulation across isolated/non-isolated topologies |
| Programmable timing & blanking | Independent BLANK and DELAY pins allow tuning of leading-edge noise immunity and synchronous rectifier dead-time-critical for SiC/GaN compatibility |
Applications
| Telecom Bus Converter | Industrial DC/DC Module |
|---|---|
Use Scenario: 36V–72V telecom input powering 12V/20A semi-regulated backplane bus with strict efficiency and space constraints. IC Role / Device Role / Timing Role: Primary-side PWM controller managing single-MOSFET forward topology, providing synchronous rectifier timing (SOUT), and adaptive duty-cycle clamp to prevent transformer saturation at high input. Use Value: Enables >92% efficiency at full load using discrete Si MOSFETs, while maintaining <1% output deviation across line/load transients without additional post-regulation. |
Use Scenario: Isolated 48V input to 12V/15A output for PLC I/O modules requiring extended temperature operation and long-term reliability. IC Role / Device Role / Timing Role: Current-mode controller implementing soft-start, UVLO (via SD_VSEC), and precision OC protection-ensuring robust startup and fault recovery in harsh factory environments. Use Value: Eliminates need for external supervisor IC; integrated 1.23V FB reference and 2.5V VREF reduce BOM count by 3 components versus discrete solutions. |
| High-Density Power Supply | Medical Isolated Converter |
Use Scenario: Compact 500W AC/DC front-end with forward-derived secondary stage targeting <1.5U rack-mount form factor. IC Role / Device Role / Timing Role: Core controller enabling >50% duty cycle operation via volt-second clamp-maximizing transformer and MOSFET utilization to shrink magnetics and heatsink size. Use Value: Reduces transformer volume by 35% and primary MOSFET conduction loss by 22% compared to 50%-clamped alternatives at 48V input. |
Use Scenario: 24V isolated DC/DC for patient-connected monitoring equipment requiring reinforced isolation and low EMI. IC Role / Device Role / Timing Role: Controller with programmable slope compensation and leading-edge blanking-suppressing noise coupling into isolated feedback path and meeting CISPR-11 Class B limits. Use Value: Achieves <10mVpp output ripple without secondary LC filtering; slope compensation resistor allows loop bandwidth tuning to match opto-coupler latency. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar forward-converter controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3748IMS#TRPBF | Integrated transformer-driver gate drive; no SOUT pin; fixed 100kHz–1MHz range; requires external VCC bootstrap | Targeted at flyback/isolated buck; lacks adaptive volt-second clamp and synchronous rectifier timing signals | Select when transformer-isolated gate drive is required and forward topology is not used |
| UCC2891DR | Fixed 500kHz frequency; no programmable slope compensation; 1.25V FB reference; no SOUT output | Designed for cost-sensitive telecom DC/DC; limited to ≤50% duty cycle; no volt-second clamp | Select only for non-saturating transformer designs with fixed input and minimal transient requirements |
Compared with LT3748IMS#TRPBF and UCC2891DR, the LT1952IGN#TRPBF uniquely provides both adaptive volt-second clamp and dedicated SOUT timing-making it the only option among the three that enables reliable >50% duty cycle operation with synchronous rectification in forward converters.
Availability
LT1952IGN#TRPBF is available at Aetrix Electronics and suitable for telecommunications power supplies, industrial distributed power systems, and isolated DC/DC converters requiring stable component supply, extended temperature operation, and high-efficiency forward topology control.
Supply support for LT1952IGN#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) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT1952IGN#TRPBF belongs to Linear's legacy high-efficiency PWM controller product line, specifically engineered for space-constrained, high-reliability forward converter applications where transformer reset safety and synchronous rectifier timing precision are critical.
FAQ
What is the operating temperature range for the LT1952IGN#TRPBF?
The LT1952IGN#TRPBF is rated for –40°C to +125°C junction temperature (I-grade). This specification is fully tested and guaranteed-not just assured by design-making it suitable for industrial telecom equipment deployed in uncontrolled ambient environments. The part uses a 16-pin SSOP package with thermal characteristics (θJA = 110°C/W) validated under real PCB conditions per JEDEC JESD51-2.
How does the LT1952IGN#TRPBF implement adaptive duty-cycle clamping?
The LT1952IGN#TRPBF implements adaptive duty-cycle clamping via the SD_VSEC and SS_MAXDC pins. SD_VSEC is resistively divided from the system input voltage to generate a voltage proportional to input-higher VIN lowers the maximum allowable duty cycle. SS_MAXDC is set by a resistor divider from VREF to define the initial clamp level. Together, they form a capacitorless, oscillator-error-immune volt-second clamp that prevents transformer saturation during line surges or load steps.
Can the LT1952IGN#TRPBF be synchronized to an external clock?
Yes, the LT1952IGN#TRPBF supports external synchronization via the SYNC pin (Pin 4). It accepts logic-level signals with 10%–90% duty cycle and operates up to 1.5× the internal oscillator frequency (maximum 500kHz). The SYNC input has 18kΩ internal resistance and a 1.5V–2.2V switching threshold, allowing direct connection to CMOS or LVDS clock sources without level-shifting.
What is the purpose of the SOUT pin on the LT1952IGN#TRPBF?
The SOUT pin on the LT1952IGN#TRPBF provides a phase-aligned, ±50mA, 12V-clamped sync signal for controlling secondary-side synchronous rectifiers in forward converters. Unlike the main OUT driver, SOUT is optimized for timing fidelity-not power delivery-and its rising edge is programmably delayed (via DELAY pin resistor) relative to OUT to maximize conduction overlap and minimize body-diode losses in SR MOSFETs.
Does the LT1952IGN#TRPBF support isolated feedback configurations?
Yes, the LT1952IGN#TRPBF supports isolated feedback via its true op-amp COMP pin. When FB is tied to VREF, the error amplifier output is disabled and COMP becomes a high-impedance node-allowing optocoupler-based feedback loops where the phototransistor collector connects to COMP and emitter to GND. This configuration maintains stability across wide temperature ranges and enables tight regulation in medical or industrial isolated supplies.
LT1952IGN#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-Down
- Output Configuration:
- Positive, Isolation Capable
- Topology:
- Forward Converter
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 9.25V ~ 25V
- Frequency - Switching:
- 100kHz ~ 500kHz
- Duty Cycle (Max):
- 90%
- Synchronous Rectifier:
- Yes
- 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
LT1952IGN#TRPBF FAQ
1.How can I place an order for LT1952IGN#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1952IGN#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 LT1952IGN#TRPBF reliable?
The price and inventory of LT1952IGN#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1952IGN#TRPBF is usually 5 days.
3.What payment methods are accepted for LT1952IGN#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1952IGN#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1952IGN#TRPBF?
LT1952IGN#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1952IGN#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 LT1952IGN#TRPBF?
For technical support, including LT1952IGN#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1952IGN#TRPBF requirements.
6.How does Aetrix verify that LT1952IGN#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT1952IGN#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 LT1952IGN#TRPBF meets industry standards.
7.What is the process for return or replacement of LT1952IGN#TRPBF?
All LT1952IGN#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1952IGN#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 LT1952IGN#TRPBF part is unused and in its original packaging.
Return procedure for LT1952IGN#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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