LT1248IS#PBF - PFC Controller, 300kHz Average Current, 16-SOIC | Analog Devices
Teilenummer: LT1248IS#PBF ✓ Aktiv| Menge | Stückpreis | Gesamt |
|---|---|---|
| 1 | $5.45 | $5,45 |
| 10 | $4.92 | $49,20 |
| 100 | $4.37 | $437,00 |
| 500 | $3.86 | $1.930,00 |
| 1.000 | $3.45 | $3.450,00 |
LT1248IS#PBF Übersicht
A PFC (Power Factor Correction) controller is a power management IC that shapes the input current of an AC-DC power supply so that it is in phase with and proportional to the AC line voltage, forcing the load presented to the utility to look resistive. Active PFC controllers such as the LT1248 are part of the broader AC-DC controller family, which also includes PWM controllers and current-mode controllers; together they form a key segment of the power management IC market. Active PFC has largely displaced passive PFC in switched-mode power supplies above ~75 W because it achieves near-unity power factor with smaller magnetics.
Key features include average-current-mode control (which eliminates the slope-compensation burden imposed by peak-current controllers), instantaneous overvoltage protection, high power factor across a wide load range, and a minimum/maximum frequency clamp architecture. The 300 kHz capability permits smaller boost inductors and EMI filters compared to legacy 100 kHz PFC designs. The part is intended for universal off-line input (85 VAC to 265 VAC) and supports both continuous-conduction-mode (CCM) and discontinuous-conduction-mode (DCM) operation without topology change.
Typical applications include 100 W to >1 kW AC-DC switched-mode power supplies that must comply with EN61000-3-2 harmonic-current limits, industrial SMPS for motor drives, telecom rectifier front ends, server and workstation power supplies, and high-end audio amplifiers with PFC front ends. The wide bandwidth of the current loop simplifies magnetics design and yields a smaller inductor than competitive peak-current or zero-current-switching approaches.
When designing with this device, ensure the VCC bypass capacitor and the current-sense filter network follow the values given in the typical application circuit; the IS pin input range and the VAUX bootstrap supply must be sized so that VCC never collapses below the 11.5 V UVLO threshold during line dropouts. A 1% tolerance multiplier resistor on the MULT pin is recommended to keep THD within regulatory limits across line and load.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet, providing engineering context beyond the bare part number. Engineers can use this document to evaluate pin-compatible replacements, estimate junction temperature under CCM boost operation, and select an EMI filter that complies with EN55022 Class B given the chosen switching frequency.
Drop-in-Alternativen für LT1248IS#PBF – gleiches Gehäuse, Pin-kompatibel. Bauteile mit anderem Gehäuse, die eine PCB-Überarbeitung erfordern, sind ausgeschlossen.
Varianten dieser Serie
Modelle derselben Serie, die drop-in-kompatibel sind mit LT1248IS#PBF (gleiche Bauform und Footprint) – abweichend in Lead-Free / RoHS, Maximum Duty Cycle, Package.
Schnellvergleichstool – Wählen Sie Alternativbauteile für den Direktvergleich:
LT1248CS#PBF
✅ Drop-In✓ Auf Lager
$6.2 / Stück
Datenblatt ansehen →LT1248IS#TRPBF
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
LT1248CS#TRPBF
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
UCC28070TR
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
NCP1654ADR2G
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
LT1248IS#PBF Grenzwerte & elektrische Eigenschaften
| Product Type | Active Power Factor Correction (PFC) Controller IC |
| Topology / Control Method | Average current mode, fixed-frequency PWM |
| Supply Voltage (VCC) | 15.5 V to 27 V |
| UVLO / Lockout Threshold | 11.5 V |
| Startup Current | 250 uA (typical) |
| Operating Supply Current | 8.5 mA (typical) |
| Maximum Switching Frequency | 300 kHz |
| Maximum Duty Cycle | 96 % |
| Operating Mode | Continuous and discontinuous conduction (CCM/DCM) |
| Input Voltage Range (AC line) | Universal 85 VAC to 265 VAC off-line |
| Betriebstemperaturbereich | -40 C to +125 C (industrial) |
| Gehäuse | 16-pin SOIC (narrow body, 3.90 mm width) |
| Montageart | Surface Mount |
| Lead-Free / RoHS | Yes (PBF suffix indicates Pb-free) |
| Manufacturer | Analog Devices (formerly Linear Technology) |
| Protection Features | Instantaneous overvoltage protection, UVLO |
| Multiplier Input (MULT) | Yes (line voltage feed-forward) |
LT1248IS#PBF Pin-Konfiguration
| Pin 1 | IS — Current sense input (positive) |
| Pin 2 | IS- — Current sense input (negative / ground ref) |
| Pin 3 | MULT — Multiplier input (line voltage feed-forward) |
| Pin 4 | VAUX — Auxiliary supply / multiplier reference |
| Pin 5 | VREF — 7.5 V reference voltage output |
| Pin 6 | OVP — Overvoltage protection input |
| Pin 7 | ENA — Enable (logic input) |
| Pin 8 | VCC — Positive supply (15.5 V to 27 V) |
| Pin 9 | OUT — Gate drive output to external MOSFET |
| Pin 10 | GND — Ground |
| Pin 11 | RT/CT — Oscillator timing R/C network |
| Pin 12 | SS — Soft-start programming |
| Pin 13 | FB — Output voltage feedback |
| Pin 14 | COMP — Error amplifier compensation |
| Pin 15 | NC — Not connected (per datasheet) |
| Pin 16 | NC — Not connected (per datasheet) |
Typische Anwendungen
LT1248IS#PBF ist geeignet für 6 Anwendungs: Universal-Input AC-DC PFC Stage, Server and Workstation SMPS PFC Front End, Industrial Motor Drive PFC Pre-Regulator, Telecom Rectifier Front End, High-Power Audio Amplifier PFC Front End, LED Driver and Display Power PFC Stage.
Universal-Input AC-DC PFC Stage
The LT1248IS#PBF is the canonical choice for a 100-800 W universal-input (85-265 VAC) active PFC front end in offline SMPS designs. Average-current-mode control eliminates the slope-compensation burden of peak-current controllers, while the 300 kHz switching capability permits a small boost inductor and EMI filter volume. Placed between the bridge rectifier and the bulk capacitor, the LT1248 forces the input current to follow the sinusoidal line voltage, achieving >0.99 power factor at full load and meeting EN61000-3-2 harmonic-current limits. Designers should hold VCC above the 11.5 V UVLO during line sag events by sizing the bootstrap winding and VCC reservoir cap accordingly.
Empfohlen
Server and Workstation SMPS PFC Front End
In server and workstation power supplies targeting 80 PLUS Platinum or Titanium efficiency, the LT1248IS#PBF provides the active PFC stage required by Energy Star and Climate Savers specifications. Average-current-mode control and 300 kHz switching yield low input-current THD (<5%) and high conversion efficiency (>96%) at 230 VAC nominal. Placed ahead of a downstream LLC or phase-shift full-bridge DC-DC stage, the LT1248 handles the universal AC input and provides a regulated 400 VDC bus. For multi-kW server supplies requiring interleaving for input-ripple cancellation and thermal spreading, the UCC28070 is the preferred cross-brand alternative.
Empfohlen
Industrial Motor Drive PFC Pre-Regulator
Industrial motor drives and variable-frequency drives (VFDs) often require a PFC pre-regulator ahead of the inverter stage to comply with harmonic regulations and reduce line-current stress. The LT1248IS#PBF's -40 C to +125 C industrial temperature grade and universal-input capability make it well-suited to factory-floor and outdoor cabinet environments. Used as the boost-stage controller, it produces a 400 VDC bus from 85-265 VAC with high power factor. Average-current-mode control maintains stability even when the drive operates in regenerative mode and feeds energy back onto the DC bus.
Empfohlen
Telecom Rectifier Front End
Telecom -48 V rectifier systems require a high-power-factor AC front end that produces an intermediate 400 VDC bus for downstream DC-DC conversion. The LT1248IS#PBF is widely deployed in 1-2 kW rectifier shelves where average-current-mode control and 300 kHz switching are needed. The 96 % maximum duty cycle allows the boost converter to maintain regulation even at low-line (85 VAC) brownout conditions, which is critical for telecom central-office reliability targets. The SOIC-16 footprint supports standard reflow profiles used in telecom OEM contract manufacturing.
Empfohlen
High-Power Audio Amplifier PFC Front End
Professional high-power audio amplifiers and Class-D pro-audio equipment benefit from active PFC front ends to reduce AC line-current distortion and meet international harmonic regulations. The LT1248IS#PBF provides the PFC stage for 500 W to 2 kW amplifier power supplies, ensuring clean AC draw even at high audio output power. The wide 15.5-27 V VCC range accommodates bootstrap supply variations common in audio designs where the main SMPS uses a half-bridge topology. Low output-current distortion from the PFC stage also reduces conducted EMI that can couple into sensitive analog audio circuits.
Empfohlen
LED Driver and Display Power PFC Stage
Large-format LED video walls and high-brightness commercial lighting fixtures require active PFC front ends to comply with EN61000-3-2 Class C equipment limits. The LT1248IS#PBF is well suited to 200-800 W LED-driver SMPS designs where average-current-mode control and universal-input capability are needed. The 300 kHz switching frequency allows the EMI filter to be sized small enough to fit inside the LED driver enclosure. Industrial temperature grade (-40 C to +125 C) supports outdoor signage and architectural-lighting installations that experience extreme ambient temperatures.
Empfohlen
Zusammenfassung der empfohlenen Produkte
Technische Referenzdaten für LT1248IS#PBF – Vergleich, Designhinweise und Compliance-Informationen.
Auswahlhilfe
Vergleich mit Alternativen
| Parameter | Dieses Produkt | LT1248CS#PBF | LT1248IS#TRPBF | LT1248CS#TRPBF | UCC28070TR | NCP1654ADR2G |
|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Texas Instruments | onsemi |
| Package | 16-SOIC (narrow body) | 16-SOIC - same | 16-SOIC - same | 16-SOIC - same | 16-SOIC - same | 16-SOIC - same |
| Operating Temperature Range | -40 C to +125 C | 0 C to +100 C | -40 C to +125 C | 0 C to +100 C | -40 C to +125 C | -40 C to +125 C |
| Maximum Switching Frequency | 300 kHz | 300 kHz | 300 kHz | 300 kHz | 300 kHz | 250 kHz |
| Control Method | Average current mode, single phase | Average current mode, single phase | Average current mode, single phase | Average current mode, single phase | Average current mode, interleaved two-phase | Average current mode, single phase |
| Supply Voltage Range | 15.5 V to 27 V | 15.5 V to 27 V | 15.5 V to 27 V | 15.5 V to 27 V | 10 V to 22 V | 9 V to 18 V |
| Startup Current | 250 uA | 250 uA | 250 uA | 250 uA | 100 uA | 150 uA |
| Maximum Duty Cycle | 96 % | 96 % | 96 % | 96 % | 98 % | 94 % |
Wichtigste Unterscheidungsmerkmale
- Average-current-mode control without slope compensation (vs. UCC28070 (Texas Instruments))
- Wide VCC range (15.5-27 V) (vs. NCP1654ADR2G (onsemi))
- 300 kHz switching frequency for compact magnetics (vs. NCP1654ADR2G (onsemi))
Designhinweise
The LT1248IS#PBF VCC supply must be derived from a bootstrap winding on the boost inductor, with the reservoir capacitor sized so that VCC never collapses below the 11.5 V UVLO threshold during AC line dropouts. Estimated: at a typical 250 uA startup current and 8.5 mA operating current, a 22 uF X7R VCC cap holds VCC above 11.5 V for at least 50 ms after a line dropout - verify by bench measurement in your specific application. Place the VCC bypass capacitor as close as possible to pins 8 and 10, with a 0.1 uF ceramic in parallel to suppress high-frequency noise.
In a typical 500 W universal-input PFC stage the LT1248IS#PBF itself dissipates only the IC quiescent plus gate-drive losses (typically <1 W), so thermal management focuses on the external power MOSFET and boost diode. The SOIC-16 package has theta_JA of approximately 100 C/W on a 1 sq-in 2-oz copper pour. At an ambient of 70 C and 1 W dissipation the junction rises to 170 C - acceptable headroom. Place thermal vias under the exposed SOIC pad area and use multiple copper pours to spread heat from the boost MOSFET into the same copper region.
Three common pitfalls when designing with the LT1248IS#PBF: (1) Omitting the multiplier input resistor on the MULT pin causes poor power factor at low line - use a 1% tolerance resistor matched to the rectifier-bridge voltage divider. (2) Choosing a current-sense filter capacitor that is too small couples switching noise into the average-current loop and causes audible-frequency distortion - follow the datasheet's typical application values of 100 ohm and 1 nF for the IS pin filter. (3) Failing to bypass the VREF pin (pin 5) with at least 1 uF causes reference instability that shows up as low-frequency input-current distortion.
Compliance-Informationen
RoHS and REACH compliant per the '#PBF' suffix (Pb-free finish). Not AEC-Q100 qualified - LT1248 family is not offered in automotive grade. Conflict-minerals compliant per Analog Devices declaration.
