Overview
The UC2842BN, produced by STMicroelectronics, is a high-performance current mode PWM (Pulse Width Modulation) controller. This IC is part of the UC284xB and UC384xB family, designed to implement off-line or DC to DC fixed frequency current mode control schemes with a minimal external parts count. It features a trimmed oscillator for precise frequency control, automatic feed-forward compensation, and latching PWM for cycle-by-cycle current limiting. The device is suitable for driving N-Channel MOSFETs and includes a high current totem pole output stage.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Supply Voltage (Vi) | - | - | 30 | V |
| Output Current (IO) | - | - | ±1 A | A |
| Output Energy (Capacitive Load) | - | - | 5 µJ | µJ |
| Reference Output Voltage (Vref) | 4.95 | 5.00 | 5.05 | V |
| Oscillator Frequency | 48 | 50 | 52 | kHz |
| Under-Voltage Lockout Start Threshold | 14.5 | 16 | 17.5 | V |
| Maximum Duty Cycle | 94 | 96 | 100 | % |
| Start-up Current (Ist) | 0.3 | 0.5 | 0.5 | mA |
| Operating Supply Current (Ii) | 12 | 17 | 17 | mA |
| Storage Temperature Range (Tstg) | -65 | - | 150 | °C |
| Junction Operating Temperature (TJ) | -40 | - | 150 | °C |
Key Features
- Trimmed oscillator for precise frequency control up to 500 kHz.
- Current mode operation with automatic feed-forward compensation.
- Latching PWM for cycle-by-cycle current limiting.
- Internally trimmed reference with under-voltage lockout and hysteresis.
- High current totem pole output stage suitable for driving N-Channel MOSFETs.
- Low start-up and operating current.
- Different under-voltage lockout thresholds and maximum duty cycle ranges for various applications.
- Error amplifier output available for loop compensation.
Applications
- Off-line power supplies.
- DC to DC converters.
- Switch-mode power supplies.
- High-frequency power conversion systems.
- Industrial power supplies and control systems.
Q & A
- What is the primary function of the UC2842BN?
The UC2842BN is a high-performance current mode PWM controller used for implementing off-line or DC to DC fixed frequency current mode control schemes.
- What is the typical oscillator frequency of the UC2842BN?
The typical oscillator frequency is around 50 kHz, but it can range from 48 kHz to 52 kHz.
- What are the under-voltage lockout thresholds for the UC2842BN?
The start threshold is between 14.5V and 17.5V, and the minimum operating voltage after turn-on is between 9V and 11.5V.
- What is the maximum duty cycle of the UC2842BN?
The maximum duty cycle can approach 100%.
- What is the output current capability of the UC2842BN?
The output can source or sink up to ±1 A.
- What is the power dissipation limit for the UC2842BN at 25°C?
The power dissipation limit is 1.25 W for the Minidip package and 800 mW for the SO8 package.
- What are the storage and operating temperature ranges for the UC2842BN?
The storage temperature range is -65°C to 150°C, and the junction operating temperature range is -40°C to 150°C.
- Can the UC2842BN be used in high-frequency applications?
Yes, it is suitable for high-frequency power conversion systems up to 500 kHz.
- How does the UC2842BN handle cycle-by-cycle current limiting?
It uses latching PWM for cycle-by-cycle current limiting.
- What type of MOSFETs can the UC2842BN drive?
The UC2842BN is designed to drive N-Channel MOSFETs.
