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Analog Devices Inc. LT1952EGN-1#PBF
- Part No.:
- LT1952EGN-1#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
LT1952EGN-1#PBF.pdf
- Description:
- IC REG CTRLR FWRD CONV 16SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:275
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Product details
Overview
LT1952EGN-1#PBF from Analog Devices (formerly Linear Technology) is a current-mode PWM controller optimized for single-switch synchronous forward converters, featuring programmable 100–500 kHz switching frequency, precision 107 mV overcurrent threshold, and adaptive volt-second clamp for transformer reset protection. It drives primary-side N-MOSFETs and provides synchronized SOUT output for secondary-side synchronous rectification in 36–72 V input, 12 V/20 A bus converters.
For engineers reviewing the LT1952EGN-1#PBF datasheet, LT1952EGN-1#PBF pinout, LT1952EGN-1#PBF application, or LT1952EGN-1#PBF equivalent, key selection considerations include its low 400 µA start-up current, VIN ON/OFF thresholds of 7.75 V / 6.5 V, 16-pin SSOP package, synchronous rectifier timing delay control, and programmable slope compensation for wide inductor/MOSFET compatibility.
Technical Context
The LT1952EGN-1#PBF implements current-mode control with a true op-amp error amplifier (65–85 dB open-loop gain, 3 MHz unity-gain bandwidth), enabling flexible compensation networks for isolated and non-isolated topologies. Its adaptive volt-second clamp uses resistor-ratio programming via SD_VSEC and SS_MAXDC pins-eliminating external capacitors and reducing oscillator drift dependency.
It integrates dual gate drivers: OUT delivers ±1 A peak drive clamped to 13 V for primary MOSFETs, while SOUT provides ±50 mA peak drive clamped to 12 V for synchronous rectifiers, with programmable tDELAY (40–120 ns) between rising edges to optimize forward converter efficiency. Leading edge blanking (180–540 ns) and hiccup-mode short-circuit protection are hardware-implemented.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | Programmable 100–500 kHz via ROSC resistor; enables compact magnetics and EMI optimization in 25–500 W power systems. |
| Overcurrent Threshold | Precision 107 mV (±9 mV), duty-cycle independent; triggers hiccup-mode soft-start for low-stress short-circuit recovery. |
| VIN Start-up Current | 400 µA typical at 7.75 V turn-on; allows micropower bootstrap start from low-input-voltage rails without auxiliary winding. |
| UVLO Thresholds | VIN ON = 7.75 V, OFF = 6.5 V (1.25 V hysteresis); SD_VSEC turn-off threshold = 1.32 V with 10 µA hysteresis for programmable system UVLO. |
| Gate Drive Outputs | OUT: ±1 A, 13 V clamp; SOUT: ±50 mA, 12 V clamp; both feature active pull-off in shutdown for safe FET biasing. |
| Error Amplifier | True op-amp with 1.226 V FB reference, 65–85 dB gain, 3 MHz GBW; supports Type II/III compensation for fast load transient response. |
| Synchronous Timing Delay | tDELAY programmable 40–120 ns via DELAY pin resistor; aligns SOUT-to-OUT edge for optimal synchronous rectifier conduction in forward topology. |
Pinout & Package
LT1952EGN-1#PBF is housed in a 16-lead plastic SSOP package (GN grade), with exposed pad for thermal performance. Pin functions are validated per Linear Technology's official datasheet (19521fe) and confirmed on Analog Devices' product page.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| COMP (1) | Error amplifier output | Drives external compensation network; voltage (0.8–2.5 V) maps linearly to ISENSE current (0–220 mV); disabled when FB = VREF. |
| FB (2) | Feedback input | Compares output voltage divider against 1.226 V internal reference; open or tied to VREF disables regulation loop. |
| ROSC (3) | Oscillator programming | Resistor to ground sets fOSC from 100–500 kHz; nominal pin voltage = 1.0 V. |
| SYNC (4) | External clock input | Accepts logic-level signal (10–90% duty cycle); synchronizes internal oscillator up to 1.5× fOSC (max 500 kHz). |
| SS_MAXDC (5) | Soft-start & max duty clamp | Capacitor-resistor network ramps voltage to control soft-start timing; voltage level sets adaptive duty cycle limit (e.g., 1.84 V → 72%). |
| VREF (6) | 2.5 V reference output | Supplies internal circuitry and external bias; sources up to 2.5 mA; requires 0.1 µF ceramic bypass to GND. |
| SD_VSEC (7) | Volt-second clamp & UVLO | Resistive divider from input defines transformer reset guardrail and system undervoltage lockout; 1.32 V threshold with 10 µA hysteresis. |
| GND (8) | Analog ground | Reference for FB, COMP, ROSC, SYNC, SS_MAXDC, VREF, SD_VSEC, BLANK, OC, DELAY; separate from PGND. |
| BLANK (9) | Leading edge blanking control | Resistor to ground sets blanking time (180–540 ns); prevents false current-limit trips during MOSFET turn-on noise. |
| ISENSE (10) | Primary current sense input | Connects to source of primary N-MOSFET; slope compensation programmed via series resistor; max threshold = 220 mV. |
| OC (11) | Dedicated overcurrent input | Hardwired 107 mV threshold; independent of duty cycle; triggers immediate soft-start latch on fault. |
| DELAY (12) | Synchronous timing delay | Resistor to ground programs tDELAY (40–120 ns) between SOUT and OUT rising edges for optimal rectifier timing. |
| PGND (13) | Power ground | Return path for OUT and SOUT drivers; must be connected to GND at single point near IC for noise immunity. |
| OUT (14) | Primary MOSFET gate driver | ±1 A peak drive, 13 V clamp; active pull-off in shutdown; rise/fall times < 50/30 ns into 1 nF. |
| VIN (15) | Main supply input | Operates from 36–72 V system rail; internal UVLO (7.75 V ON / 6.5 V OFF); requires local 10 µF + 0.1 µF decoupling. |
| SOUT (16) | Synchronous rectifier sync output | ±50 mA peak drive, 12 V clamp; phase-aligned with OUT; used to drive secondary-side N-MOSFET gates. |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectifier control (SOUT) | Enables >90% efficiency in forward converters by precisely timing secondary-side MOSFETs with programmable 40–120 ns delay relative to OUT. |
| Adaptive volt-second clamp | Uses SD_VSEC and SS_MAXDC resistor ratios-not external capacitors-to dynamically limit duty cycle based on input voltage, preventing transformer saturation. |
| Low-stress hiccup protection | Combines 107 mV OC threshold with true PWM soft-start (via SS_MAXDC ramp) to limit inrush and recover safely after overloads without latching off. |
| Programmable slope compensation | Adjustable via ISENSE-series resistor to stabilize current-mode loop across wide inductance/MOSFET RDS(on) ranges, supporting multi-kHz bandwidths. |
| True op-amp error amplifier | Delivers 65–85 dB gain and 3 MHz bandwidth, enabling robust Type II/III compensation for fast load transients in telecom and industrial DC/DC systems. |
| Low-power start-up | 400 µA start-up current at 7.75 V enables direct bootstrap from high-voltage input rails using simple RC networks-no auxiliary winding required. |
Applications
| Telecom Bus Converter | Industrial Isolated DC/DC |
|---|---|
|
Use Scenario: 36–72 V telecom input converted to semi-regulated 12 V/20 A output for line cards and baseband processing. IC Role / Device Role / Timing Role: Primary-side PWM controller managing single-MOSFET forward topology with synchronous rectification timing via SOUT/OUT delay. Use Value: Adaptive volt-second clamp enables >50% duty cycle operation at high input voltages, improving transformer and MOSFET utilization while avoiding saturation. |
Use Scenario: 48 V factory automation rail powering isolated 5 V/10 A logic supplies with tight transient response requirements. IC Role / Device Role / Timing Role: Current-mode controller implementing optocoupler feedback loop with COMP-driven error amplifier for stable regulation under dynamic loads. Use Value: True op-amp error amplifier (3 MHz GBW) and programmable slope compensation ensure stable loop behavior across temperature and component tolerances. |
| Distributed Power Architecture | High-Efficiency Forward Converter |
|
Use Scenario: Central 48 V bus feeding multiple point-of-load converters in server racks or data center power shelves. IC Role / Device Role / Timing Role: Controller for semi-regulated 12 V intermediate bus converter delivering up to 500 W with minimal external components. Use Value: 100–500 kHz programmable frequency allows EMI spread-spectrum tuning and magnetic size optimization for space-constrained modules. |
Use Scenario: High-efficiency 25–500 W forward converter for medical or test equipment requiring low-noise, low-ripple outputs. IC Role / Device Role / Timing Role: Dual-output gate driver (OUT + SOUT) with precise timing control ensures zero-voltage switching of secondary rectifiers. Use Value: Programmable leading edge blanking (180–540 ns) eliminates false triggering from MOSFET switching noise, improving reliability in noisy environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar forward converter controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3900 | Dual N-channel synchronous rectifier driver only; no PWM controller, no FB/COMP/ISENSE; requires external controller. | Used downstream of LT1952EGN-1#PBF to drive secondary-side MOSFETs; not a functional replacement. | Select LTC3900 only as companion device for enhanced synchronous rectification-never as standalone controller alternative. |
| UCC28911 | PSR flyback controller with integrated 700 V MOSFET; no SOUT output; no volt-second clamp; fixed 70 kHz frequency. | Targets low-cost, low-power (<25 W) isolated flyback designs-not forward topology or high-power applications. | UCC28911 is unsuitable for forward converters or >50 W systems; use only for cost-sensitive, low-power PSR flyback where isolation and simplicity outweigh efficiency needs. |
Compared with LT1952EGN-1#PBF, LTC3900 serves a complementary role in synchronous rectification but lacks all control functions, while UCC28911 targets a different topology and power class-neither offers the adaptive volt-second clamp, programmable frequency, or dual-gate timing essential for high-efficiency forward conversion.
Availability
LT1952EGN-1#PBF is available at Aetrix Electronics and suitable for telecommunications power supplies, industrial isolated DC/DC converters, and distributed power architectures requiring stable component supply, long-term lifecycle support, and guaranteed -40°C to +125°C operation.
Supply support for LT1952EGN-1#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) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving aerospace, industrial, automotive, and communications markets.
The LT1952EGN-1#PBF belongs to Linear Technology's legacy PWM controller product line, specifically engineered for high-efficiency, single-switch forward converters in telecom and industrial power systems demanding reliability, low start-up current, and adaptive transformer protection.
FAQ
What is the key difference between LT1952EGN-1#PBF and LT1952EGN#PBF?
The LT1952EGN-1#PBF features lower VIN undervoltage lockout thresholds (7.75 V ON / 6.5 V OFF) and reduced 400 µA start-up current versus the LT1952EGN#PBF (14.25 V ON / 8.75 V OFF, 460 µA). This makes LT1952EGN-1#PBF better suited for systems with lower input voltage rails or tighter bootstrap constraints. Both share identical pinout, package, and core functionality.
How does the volt-second clamp in LT1952EGN-1#PBF prevent transformer saturation?
The LT1952EGN-1#PBF implements an adaptive volt-second clamp using SD_VSEC and SS_MAXDC pins. When SD_VSEC is resistively divided from the input voltage, rising input increases the clamp's sensitivity-automatically reducing maximum duty cycle to maintain safe volt-second balance across the transformer. This avoids saturation without fixed 50% duty limits or external timing capacitors.
Can LT1952EGN-1#PBF drive both primary and secondary MOSFETs directly?
Yes-LT1952EGN-1#PBF integrates two dedicated gate drivers: OUT delivers ±1 A peak current (13 V clamp) for primary-side N-MOSFETs, while SOUT provides ±50 mA (12 V clamp) for secondary-side synchronous rectifiers. The programmable DELAY pin adjusts timing between their rising edges to maximize forward converter efficiency.
What is the purpose of the OC pin on LT1952EGN-1#PBF, and how does it differ from ISENSE?
The OC pin on LT1952EGN-1#PBF provides a dedicated, precision 107 mV overcurrent threshold independent of duty cycle-triggering immediate hiccup-mode soft-start on fault. In contrast, ISENSE feeds the main current-mode control loop with a programmable 0–220 mV threshold and supports slope compensation; OC is strictly for fault protection, not regulation.
Does LT1952EGN-1#PBF require an external oscillator or crystal?
No-LT1952EGN-1#PBF contains an internal oscillator programmed via a single resistor on the ROSC pin (100–500 kHz range). It also supports external synchronization via the SYNC pin, accepting logic-level signals up to 500 kHz, but no crystal or external oscillator component is needed for autonomous operation.
LT1952EGN-1#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tube
- 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):
- 6.82V ~ 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
LT1952EGN-1#PBF FAQ
1.How can I place an order for LT1952EGN-1#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1952EGN-1#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 LT1952EGN-1#PBF reliable?
The price and inventory of LT1952EGN-1#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1952EGN-1#PBF is usually 5 days.
3.What payment methods are accepted for LT1952EGN-1#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1952EGN-1#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1952EGN-1#PBF?
LT1952EGN-1#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1952EGN-1#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 LT1952EGN-1#PBF?
For technical support, including LT1952EGN-1#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1952EGN-1#PBF requirements.
6.How does Aetrix verify that LT1952EGN-1#PBF is sourced from the original manufacturer or authorized distributors?
All LT1952EGN-1#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 LT1952EGN-1#PBF meets industry standards.
7.What is the process for return or replacement of LT1952EGN-1#PBF?
All LT1952EGN-1#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1952EGN-1#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 LT1952EGN-1#PBF part is unused and in its original packaging.
Return procedure for LT1952EGN-1#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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