Overview
The UC3846J, produced by Texas Instruments, is a current-mode PWM (Pulse Width Modulation) controller IC designed for use in a variety of DC-DC converter topologies. This integrated circuit is part of the UC3846 family and is known for its robust features and high performance in power management applications. The UC3846J is available in a 16-pin DIP (Dual In-Line Package) and is suitable for operating in temperatures from 0°C to 70°C.
Key Specifications
| Parameter | Test Conditions | Min. | Typ. | Max. | Units |
|---|---|---|---|---|---|
| Output Voltage | TJ=25°C, IO=1mA | 5.00 | 5.10 | 5.20 | V |
| Line Regulation | VIN=8V to 40V | 5 | 20 | 20 | mV |
| Load Regulation | IL=1mA to 10mA | 3 | 15 | 15 | mV |
| Temperature Stability | Over Operating Range | 0.4 | 0.4 | 0.4 | mV/°C |
| Total Output Variation | Line, Load, and Temperature | 4.95 | 5.20 | 5.25 | V |
| Output Noise Voltage | 10Hz≤ f ≤10kHz, TJ=25°C | 100 | 100 | 100 | µV |
| Oscillator Frequency | TJ=25°C | 39 | 43 | 47 | kHz |
| Sync Output High Level | Pin 8=0V | 3.9 | 4.35 | 4.35 | V |
| Shutdown Threshold Voltage | 250 | 350 | 400 | mV |
Key Features
- Built-in under-voltage lockout and soft start capabilities for safe startup and operation.
- Programmable pulse-by-pulse current limiting for enhanced protection.
- Automatic symmetry correction in push-pull configurations to ensure balanced operation.
- Feed forward compensation for improved stability.
- ±1% trimmed bandgap reference for high accuracy.
- Parallel operation capability for equal current sharing in modular power systems.
- Differential current sense amplifier with a wide common mode range.
- Double pulse suppression to prevent unwanted pulses.
- 500mA (Peak) totem-pole outputs for high drive capability.
- Shutdown function with options for complete shutdown or automatic restart.
Applications
- Boost, flyback, forward converters.
- Half-bridge and push-pull regulators.
- Positive output step-up and step-up/step-down DC-DC converters.
- Modular power systems requiring parallel operation.
- High-reliability power supplies in industrial, medical, and aerospace applications.
Q & A
- What is the operating temperature range of the UC3846J?
The UC3846J operates from 0°C to 70°C.
- What is the typical oscillator frequency of the UC3846J?
The typical oscillator frequency is 43 kHz.
- Does the UC3846J have built-in under-voltage lockout?
Yes, it does have built-in under-voltage lockout.
- What is the maximum output voltage variation over line, load, and temperature?
The maximum output voltage variation is 5.25 V.
- Can the UC3846J be used in parallel operation?
Yes, it supports parallel operation for equal current sharing in modular power systems.
- What is the peak output current of the totem-pole outputs?
The peak output current is 500 mA.
- Does the UC3846J have a shutdown function?
Yes, it has a shutdown function with options for complete shutdown or automatic restart.
- What is the typical line regulation of the UC3846J?
The typical line regulation is 20 mV.
- What is the input bias current of the error amplifier?
The input bias current of the error amplifier is typically -2.5 µA.
- What are the common applications of the UC3846J?
Common applications include boost, flyback, forward converters, half-bridge, and push-pull regulators, as well as modular power systems.
