UC3844BD1 STMicroelectronics Integrated Circuit (Small Outline Packages) In Stock
UC3844BD1 is a current-mode PWM controller IC by STMicroelectronics for boost and flyback converters. Key specs include 11.5 V to 30 V input, 1 A gate drive, 500 kHz maximum frequency, and 8-pin SOIC package. Available from stock with worldwide shipping.
- Manufacturer
- STMicroelectronics
- Package
- Small Outline Packages
- Pin Count
- 8
- Lifecycle
- ACTIVE
- Datasheet
- UC3844BD1 Datasheet PDF
- Category
- Integrated Circuit
- Price
- From $0.3032(MOQ 4)
- Temp Range
- ?°C to 70.0°C
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
Key Features
- Current-mode PWM control enables cycle-by-cycle peak current limiting for inherent short-circuit protection
- Up to 500 kHz oscillator frequency reduces transformer and filter size in compact converter designs
- 1 A totem-pole gate driver provides fast MOSFET switching without external buffer transistors
Applications
UC3844BD1 is used as the primary controller in offline flyback and boost switch-mode power supplies for industrial and telecom equipment. Its 11.5 V to 30 V operating range makes it well-suited for auxiliary supply rails derived from rectified mains through a startup resistor. The device also serves in DC-DC converter stages within uninterruptible power supplies and laboratory bench power instruments.
Specifications
| YTEOL | 7 |
| Analog IC - Other Type | SWITCHING CONTROLLER |
| Control Mode | CURRENT-MODE |
| Control Technique | PULSE WIDTH MODULATION |
| Input Voltage-Max | 30V |
| Input Voltage-Min | 11.5V |
| Input Voltage-Nom | 15V |
| JESD-30 Code | R-PDSO-G8 |
| JESD-609 Code | e4 |
| Number of Functions | 1 |
| Output Current-Max | 1A |
| Package Body Material | PLASTIC/EPOXY |
| Package Equivalence Code | SOP8,.25 |
| Package Shape | RECTANGULAR |
| Package Style | SMALL OUTLINE |
| Peak Reflow Temperature (Cel) | NOT SPECIFIED |
| Qualification Status | Not Qualified |
| Surface Mount | YES |
| Switcher Configuration | SINGLE |
| Switching Frequency-Max | 500kHz |
| Technology | BIPOLAR |
| Temperature Grade | COMMERCIAL |
| Terminal Finish | Nickel/Palladium/Gold (Ni/Pd/Au) |
| Terminal Form | GULL WING |
| Terminal Pitch | 1.27mm |
| Terminal Position | DUAL |
| Time@Peak Reflow Temperature-Max (s) | NOT SPECIFIED |
| ## UC3844BD1 Alternates Showing results | Image |
| Package | Small Outline Packages |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
| Moisture Sensitivity Level | MSL 1 |
| ECCN | EAR99 |
| HTS Code | 8542.39.00.60 |
| Country of Origin | Morocco |
Alternate & Equivalent Parts
Compatible alternatives and drop-in replacements for UC3844BD1:
suggested
suggested
suggested
Switching Controller, Current-mode, 1A, 500kHz Switching Freq-Max, BIPolar, PDSO8
Frequently Asked Questions
How does the 500 kHz oscillator capability of UC3844BD1 affect transformer design compared to lower-frequency controllers?
Running UC3844BD1 at 500 kHz allows the flyback transformer core size to shrink substantially compared to 100 kHz designs, because higher frequency reduces the volt-second product per cycle. This translates to a ferrite core roughly 4 times smaller by volume, lowering both cost and PCB footprint in the power stage.
What is the startup voltage threshold for UC3844BD1, and how should the bias supply circuit be designed?
UC3844BD1 requires at least 11.5 V on the VCC pin to start switching, with an 8.5 V undervoltage lockout release point that latches the output off during low-voltage conditions. Designers typically use a 15 V auxiliary winding and a startup resistor from the rectified bus to bring VCC above 11.5 V within the required startup time.
When evaluating UC3844BD1 versus UC3845BD1 for a flyback converter, which device suits duty-cycle-limited topologies?
UC3844BD1 is pinned for duty cycles up to 100%, making it suitable for boost converters and continuous-conduction flyback designs, whereas UC3845BD1 limits duty cycle to below 50% for two-switch forward converters. Choosing UC3844BD1 in a 30 V input flyback stage avoids the added complexity of a duty-cycle clamp circuit.
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About STMicroelectronics
STMicroelectronics is a global semiconductor leader serving customers across the spectrum of electronics applications. ST's products are found in a wide range of applications including automotive, industrial, personal electronics, and communications.
| Qty. | Unit Price | Ext. Price |
|---|---|---|
| 4+ | $0.4947 | $1.98 |
| 8+ | $0.4921 | $3.94 |
| 16+ | $0.3792 | $6.07 |
| 1500+ | $0.3350 | $502.50 |
| 2000+ | $0.3032 | $606.40 |
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