Overview
The UC3843AD1G, produced by onsemi, is a high-performance, fixed-frequency, current-mode PWM controller. It is specifically designed for off-line and DC-to-DC converter applications, offering a cost-effective solution with minimal external components. This integrated circuit features a trimmed oscillator for precise duty cycle control, a temperature-compensated reference, a high-gain error amplifier, a current sensing comparator, and a high-current totem pole output ideal for driving power MOSFETs.
Key Specifications
| Parameter | Symbol | Min. | Typ. | Max. | Unit |
|---|---|---|---|---|---|
| Supply Voltage | VCC | - | - | 30 | V |
| Output Current | IO | - | - | ±1 | A |
| Reference Output Voltage | VREF | 4.90 | 5.00 | 5.10 | V |
| Line Regulation | ΔVREF | - | - | 20 | mV |
| Load Regulation | ΔVREF | - | - | 25 | mV |
| Oscillation Frequency | f | 47 | 52 | 57 | kHz |
| Current Sense Input Voltage Gain | GV | 2.85 | 3.0 | 3.15 | V/V |
| Maximum Current Sense Input Threshold | Vth | 0.9 | 1.0 | 1.1 | V |
| Power Supply Rejection Ratio | PSRR | - | - | 70 | dB |
| Output Voltage Low State (ISink = 20 mA) | VOL | - | - | 0.4 | V |
| Output Voltage High State (ISink = 20 mA) | VOH | 13 | 13.5 | - | V |
| Under-Voltage Lockout Start Threshold | VTH(ST) | 7.8 | 8.4 | 9.0 | V |
| Minimum Operating Voltage (After Turn On) | VOPR(MIN) | 7.0 | 7.6 | 8.2 | V |
Key Features
- Trimmed oscillator for precise duty cycle control
- Temperature-compensated reference
- High-gain error amplifier
- Current sensing comparator
- High-current totem pole output for driving power MOSFETs
- Low start-up and operating current
- Undervoltage lockout with hysteresis
- Automatic feed-forward compensation
- Latching PWM for cycle-by-cycle current limiting
- Programmable output deadtime
- Direct interface with ON Semiconductor SENSEFET™ products
- Pb-free packages available
Applications
The UC3843AD1G is designed for off-line and DC-to-DC converter applications. It is particularly suitable for:
- Switch-mode power supplies
- DC-DC converters
- High-efficiency power conversion systems
- Power management in industrial and consumer electronics
Q & A
- What is the primary function of the UC3843AD1G?
The UC3843AD1G is a high-performance, fixed-frequency, current-mode PWM controller designed for off-line and DC-to-DC converter applications.
- What is the typical operating frequency of the UC3843AD1G?
The typical operating frequency is around 52 kHz, with a range of 47 kHz to 57 kHz.
- What are the under-voltage lockout thresholds for the UC3843AD1G?
The start threshold is between 7.8 V and 9.0 V, and the minimum operating voltage after turn-on is between 7.0 V and 8.2 V.
- What is the maximum output current of the UC3843AD1G?
The maximum output current is ±1 A.
- What type of output stage does the UC3843AD1G have?
The UC3843AD1G has a high-current totem pole output stage.
- Does the UC3843AD1G support cycle-by-cycle current limiting?
Yes, it supports cycle-by-cycle current limiting through its latching PWM feature.
- What is the power supply rejection ratio (PSRR) of the UC3843AD1G?
The PSRR is typically 70 dB.
- What are the available package types for the UC3843AD1G?
The device is available in 8-pin dual-in-line plastic package and 14-pin plastic surface mount (SOIC-14) package.
- Is the UC3843AD1G Pb-free?
Yes, Pb-free packages are available.
- What is the storage temperature range for the UC3843AD1G?
The storage temperature range is from -65°C to +150°C.
