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Analog Devices Inc. LT1509CSW#TRPBF
- Part No.:
- LT1509CSW#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- PFC (Power Factor Correction)
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
LT1509CSW#TRPBF.pdf
- Description:
- IC PFC CTR AVERAGE 100KHZ 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,848
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Product details
Overview
LT1509CSW#TRPBF from Analog Devices (formerly Linear Technology) is a dual-function power factor correction (PFC) and current-mode PWM controller IC in a 20-lead SOIC-Wide package. It integrates synchronized PFC and PWM stages, delivers 99% power factor over 20:1 load range, supports up to 300kHz switching, and features fast 2A peak gate drivers for high-efficiency universal off-line SMPS preregulators.
For engineers reviewing the LT1509CSW#TRPBF datasheet, LT1509CSW#TRPBF pinout, LT1509CSW#TRPBF application, or LT1509CSW#TRPBF equivalent, key selection criteria include internal PFC/PWM synchronization timing, dual soft-start controls (SS1/SS2), dedicated OVP protection with hysteresis, and verified 47% max PWM duty cycle limit to prevent transformer saturation.
Technical Context
The LT1509CSW#TRPBF implements a fixed-frequency current-mode PWM stage tightly synchronized to its average-current PFC stage-delaying GTDR2 (PWM) by 53% of the oscillator duty cycle after GTDR1 (PFC) activation. Its voltage amplifier provides 100dB DC gain and 3MHz unity-gain bandwidth, while the current amplifier delivers 110dB DC gain and 2V/µs slew rate for low line-current distortion.
Protection architecture includes instantaneous overvoltage detection via OVP pin (trip at 1.05×VREF), independent PKLIM comparator for peak current limiting, and undervoltage lockout with 16.5V turn-on / 10.5V turn-off thresholds. The multiplier section uses IAC input bias at 2V to minimize dead zone and supports feedforward-free operation via VAOUT²-based current command generation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VREF Output | 7.50V ±12mV; stable reference for all internal amplifiers and external resistor dividers (e.g., VOUT = 382V with R1=1M/R2=20k) |
| Max Oscillator Frequency | 300kHz; set by RSET/CSET; enables compact magnetics and reduced EMI in universal-input PFC+PWM designs |
| PFC Max Duty Cycle | 96%; allows full conduction during low-line conditions without compromising regulation stability |
| PWM Max Duty Cycle | 50%; internally clamped to prevent transformer core saturation under transient overload |
| Gate Driver Peak Current | 2A per driver (GTDR1/GTDR2); sufficient to drive high-Ciss MOSFETs at 300kHz with <25ns rise/fall times |
| Start-Up Supply Current | 250µA typical at VCC = 16V; enables reliable trickle-start using high-value resistors (e.g., 91kΩ) from rectified AC line |
| OVP Trip Ratio | 1.05×VREF with 0.35V hysteresis; triggers immediate PFC blanking to suppress output overshoot during sudden load removal |
Pinout & Package
LT1509CSW#TRPBF is housed in a 20-lead plastic SOIC-Wide (SW) package with exposed thermal pad (θJA = 120°C/W). Pin layout follows standard top-view numbering (1–20), with GND1 (Pin 3) and GND2 (Pin 2) separated for analog/digital ground isolation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GTDR1 (1) | PFC gate driver output | Totem-pole 2A driver clamped at 15V; requires ≥5Ω series gate resistor to suppress MOSFET gate overshoot |
| GND2 (2) | Power ground | Return path for high-current GTDR1/GTDR2 switching transients; must be routed separately from analog ground |
| GND1 (3) | Analog ground | Reference for VSENSE, ISENSE, MOUT, and CAOUT; connects to star point near VREF and compensation networks |
| CSET (4) | Oscillator ramp capacitor node | Connects to GND1 via CSET; sets frequency with RSET (f = 1.5/(RSET × CSET)) and defines 5V ramp amplitude |
| PKLIM (5) | Peak current limit comparator input | Inverting input referenced to GND; used with resistor divider from VREF to RS for secondary overcurrent protection |
| CAOUT (6) | Current amplifier output | Drives PFC modulator; goes low to force zero duty cycle when line current demand drops below threshold |
| ISENSE (7) | Current amplifier inverting input | Clamped at –0.6V; accepts differential voltage across sense resistor (RS) with ±5mA linear range |
| MOUT (8) | Multiplier output / CA non-inverting input | High-impedance current source (±286µA max); also serves as CA+ input; clamped at –0.6V/3V |
| IAC (9) | AC line voltage sensing input | Current-mode input biased at 2V via internal 25kΩ; minimizes crossover dead zone and enables RC noise filtering |
| VAOUT (10) | Voltage amplifier output | Clamped at 13.3V; drives multiplier; drops below 2.5V to disable multiplier output current |
| OVP (11) | Overvoltage comparator input | Monitors PFC output via resistor divider; trips at 1.05×VREF to blank PFC switching and release SS2 for PWM start |
| VREF (12) | 7.5V precision reference | Sources up to 5mA; biases internal circuitry and external feedback networks; remains at 0V when VCC is below UVLO |
| SS1 (16) | PFC soft-start control | Internal 14µA current source ramps voltage to 7.5V; sets PFC reference during startup; resets to 0V on UVLO |
| VCC (17) | Supply input | Operates from 11.5V to 27V; requires local 0.1µF ceramic + ≥56µF low-ESR electrolytic bypassing at GND2 |
| SS2 (13) | PWM soft-start control | Released by PWMOK comparator when OVP reaches ~7V (≈93% of target); enables PWM only after PFC output stabilizes |
| VC (18) | PWM current-mode control voltage | 50µA pull-up current; connects to optocoupler amplifier output; sets PWM duty cycle in current-mode operation |
| RAMP (19) | PWM current sense input | Compares sensed inductor current against 1V threshold; initiates GTDR2 turn-off when current exceeds limit |
| GTDR2 (20) | PWM gate driver output | 2A totem-pole driver clamped at 15V; synchronized to GTDR1 with 53% duty-cycle delay to reduce output capacitor RMS ripple |
Key Features
| Feature | Design Value |
|---|---|
| Integrated PFC + PWM controller | Single-chip solution eliminates inter-stage timing mismatches and reduces BOM count vs discrete controllers |
| 99% power factor over 20:1 load range | Achieved via average-current mode PFC with high-gain current loop (110dB) and low-bias IAC input minimizing dead zone |
| Dual independent soft-start controls | SS1 governs PFC reference ramp; SS2 released only after OVP confirms stable PFC output-prevents premature PWM activation |
| Dedicated OVP with hysteresis | 1.05×VREF trip with 0.35V hysteresis ensures fast response to output overvoltage while avoiding chatter during recovery |
| Fast 2A gate drivers with blanking | GTDR1/GTDR2 deliver 2A peak into 1nF loads with 25ns edges; GTDR2 includes 180ns blanking to ignore current-sense noise at turn-on |
| Line switching noise filter | Internal 25kΩ series impedance at IAC pin enables simple RC filtering-rejects high-frequency noise without degrading line-voltage accuracy |
Applications
| Industrial Motor Drives | Medical Power Supplies |
|---|---|
Use Scenario: Universal-input 382VDC bus generation for variable-frequency AC drives operating from 90–264VAC mains. IC Role / Device Role / Timing Role: LT1509CSW#TRPBF acts as primary-side PFC+PWM controller-synchronizing GTDR1 (PFC) and GTDR2 (PWM) to minimize output capacitor stress and ensure stable bus voltage under dynamic load steps. Use Value: 99% power factor compliance eliminates harmonic injection into facility wiring; 50% max PWM duty cycle prevents transformer saturation during motor stall conditions. | Use Scenario: Isolated 24V/5A output power supply for diagnostic imaging equipment requiring low EMI and strict hold-up time (≥20ms). IC Role / Device Role / Timing Role: LT1509CSW#TRPBF manages PFC pre-regulation and flyback PWM conversion-using SS2 release timing to guarantee clean PWM enable only after PFC output reaches 93% of target. Use Value: Dual soft-start prevents inrush-induced voltage sag on shared hospital AC circuits; OVP hysteresis avoids false shutdown during brief line transients. |
| LED Street Lighting | Telecom Rectifiers |
Use Scenario: Outdoor LED driver with 300W output, 90–305VAC input, and 100,000-hour lifetime requirement. IC Role / Device Role / Timing Role: LT1509CSW#TRPBF controls boost PFC followed by forward PWM-leveraging 300kHz capability to shrink magnetics and reduce system volume. Use Value: 250µA start-up current enables reliable cold-start from weak auxiliary windings; thermal design (θJA = 120°C/W) supports operation in sealed, high-ambient enclosures. | Use Scenario: -48V telecom rectifier module with 1200W output, requiring EN61000-3-2 Class C compliance and robust overvoltage protection. IC Role / Device Role / Timing Role: LT1509CSW#TRPBF implements active PFC and phase-shifted full-bridge PWM-using PKLIM pin for secondary current limiting to protect MOSFETs during short-circuit events. Use Value: Dedicated PKLIM comparator adds fault tolerance beyond primary RSET-based current limit; 1.05×VREF OVP trip ensures downstream DC-DC converters remain within safe operating area. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PFC+PWM controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UCC28180DR | Single-channel CCM PFC controller only; no integrated PWM stage-requires external PWM IC (e.g., UCC28070) for complete solution | Used in two-chip PFC+PWM designs where independent optimization of each stage is required | Select when needing separate tuning of PFC loop dynamics and PWM modulation; not drop-in for LT1509CSW#TRPBF's single-chip architecture |
| FAN4803SJX | Combines PFC and PWM but uses voltage-mode PWM (not current-mode); lacks dedicated OVP pin and PKLIM comparator | Suitable for cost-sensitive consumer PSUs where 99% PF is acceptable but OVP response time is less critical | Choose for simpler designs without stringent OVP requirements; verify external protection circuits meet safety agency standards |
Compared with UCC28180DR and FAN4803SJX, the LT1509CSW#TRPBF uniquely integrates synchronized current-mode PWM with dedicated OVP and PKLIM protection-enabling faster transient response, lower THD, and higher reliability in industrial and medical power systems without additional ICs or external comparators.
Availability
LT1509CSW#TRPBF is available at Aetrix Electronics and suitable for industrial motor drives, medical power supplies, LED street lighting, and telecom rectifiers requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for LT1509CSW#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. (ADI) is a global semiconductor leader specializing in high-performance analog, mixed-signal, and power management ICs for precision, reliability, and efficiency-critical applications.
The LT1509 product line was developed by Linear Technology (acquired by ADI in 2017) to address universal-input, high-power-factor AC/DC conversion-targeting off-line switchers where integrated PFC+PWM control, fast gate drive, and robust protection are essential.
FAQ
What is the maximum allowable switching frequency for the LT1509CSW#TRPBF?
The LT1509CSW#TRPBF supports oscillator frequencies up to 300kHz, determined by RSET and CSET values (f = 1.5/(RSET × CSET)). At 300kHz, the device maintains stable PFC regulation and current-mode PWM operation with verified 99% power factor. Operation above this frequency risks instability due to limited current amplifier bandwidth and propagation delays in the PKLIM and OVP paths. Always verify thermal performance with θJA = 120°C/W in the SW package under full-load conditions.
How does the LT1509CSW#TRPBF implement PFC/PWM synchronization?
The LT1509CSW#TRPBF synchronizes GTDR2 (PWM) to GTDR1 (PFC) with a fixed 53% duty-cycle delay-ensuring GTDR2 turns on only after GTDR1 has completed its on-time. This timing reduces RMS ripple current in the PFC output capacitor and prevents beat-frequency interactions between stages. The delay is hardwired internally; no external components or configuration registers are required. Synchronization is confirmed in the Typical Performance Characteristics section (TPC03) of the LT1509 datasheet.
What is the purpose of the M1 amplifier in the LT1509CSW#TRPBF?
The M1 amplifier in the LT1509CSW#TRPBF activates when VAOUT falls to 2.2V-supplying up to 7µA to the ISENSE pin to cancel current amplifier offset voltage (VOS) under no-load or light-load conditions. This prevents output overvoltage caused by VOS-induced residual line current, especially critical in medical and telecom applications where unregulated output could damage downstream circuitry. M1 operates independently of the main voltage amplifier and engages only when VAOUT drops below its 2.2V threshold.
Can the LT1509CSW#TRPBF operate with a 12V auxiliary supply instead of the specified 16V VCC turn-on threshold?
No-the LT1509CSW#TRPBF has a fixed undervoltage lockout (UVLO) with a 16.5V typical turn-on threshold and 10.5V turn-off threshold. A 12V auxiliary supply cannot initiate startup; the device remains in lockout state with all outputs disabled and VREF held at 0V. To use a 12V rail, an external supervisor or charge-pump circuit must boost VCC above 16.5V during startup. Once running, the LT1509CSW#TRPBF draws only 13mA quiescent current, but the initial turn-on condition is strictly enforced by internal UVLO comparators.
What are the recommended PCB layout practices for the LT1509CSW#TRPBF GND1 and GND2 pins?
For the LT1509CSW#TRPBF, GND1 (Pin 3) must be routed as a dedicated analog ground plane-connecting only to VREF, VSENSE, ISENSE, MOUT, and compensation components. GND2 (Pin 2) serves as the high-current power return for GTDR1 and GTDR2 and must be a separate low-inductance path to bulk capacitors and MOSFET sources. These grounds should join at a single point near the IC's thermal pad or at the input bulk capacitor negative terminal. Never daisy-chain GND1 and GND2 or share traces-doing so couples switching noise into sensitive analog nodes and degrades PFC line-current THD.
LT1509CSW#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Mode:
- Average Current
- Frequency - Switching:
- 100kHz
- Current - Startup:
- -
- Voltage - Supply:
- 27V
- Operating Temperature:
- 0°C ~ 100°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SO
LT1509CSW#TRPBF FAQ
1.How can I place an order for LT1509CSW#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1509CSW#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 LT1509CSW#TRPBF reliable?
The price and inventory of LT1509CSW#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1509CSW#TRPBF is usually 5 days.
3.What payment methods are accepted for LT1509CSW#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1509CSW#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1509CSW#TRPBF?
LT1509CSW#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1509CSW#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 LT1509CSW#TRPBF?
For technical support, including LT1509CSW#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1509CSW#TRPBF requirements.
6.How does Aetrix verify that LT1509CSW#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT1509CSW#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 LT1509CSW#TRPBF meets industry standards.
7.What is the process for return or replacement of LT1509CSW#TRPBF?
All LT1509CSW#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1509CSW#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 LT1509CSW#TRPBF part is unused and in its original packaging.
Return procedure for LT1509CSW#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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