The UC1842A/3A/4A/5A family of control ICs is a pin-for-pin compatible improved version of the UC3842/3/4/5 family. Providing the necessary features to control current mode switched mode power supplies, this family has the following improved features. Start up current is guaranteed to be less than 0.5 mA. Oscillator discharge is trimmed to 8.3 mA. During under voltage lockout, the output stage can sink at least 10 mA at less than 1.2 V for VCC over 5 V.

• Controlled Baseline
• One Assembly/Test Site, One Fabrication Site
• Extended Temperature Performance of –55°C to 125°C
• Enhanced Diminishing Manufacturing Sources (DMS) Support
• Enhanced Product Change Notification
• Qualification Pedigree(1)
• Optimized for Off-line and DC-to-DC Converters
• Low Start Up Current (<0.5 mA)
• Trimmed Oscillator Discharge Current
• Automatic Feed Forward Compensation
• Pulse-by-Pulse Current Limiting
• Enhanced Load Response Characteristics
• Under-Voltage Lockout With Hysteresis
• Double Pulse Suppression
• High Current Totem Pole Output
• Internally Trimmed Bandgap Reference
• 500 kHz Operation
• Low RO Error Amp

(1) Component qualification in accordance with JEDEC and industry standards to ensure reliable operation over an extended temperature range. This includes, but is not limited to, Highly Accelerated Stress Test (HAST) or biased 85/85, temperature cycle, autoclave or unbiased HAST, electromigration, bond intermetallic life, and mold compound life. Such qualification testing should not be viewed as justifying use of this component beyond specified performance and environmental limits.