Overview
The ADM8843ACPZ-REEL7 is a high-performance LED driver IC produced by Analog Devices Inc. This component is designed to drive white LEDs in various display applications, offering advanced features such as brightness control, low power consumption, and high current accuracy. The ADM8843 is fabricated using CMOS technology, ensuring minimal power consumption and is packaged in a 16-lead lead frame chip scale package (LFCSP).
Key Specifications
| Parameter | Min | Typ | Max | Unit | Test Conditions |
|---|---|---|---|---|---|
| Input Voltage, VCC | 2.6 | 5.5 | V | ||
| Supply Current, ICC | 2.6 | 5 | mA | All four LEDs disabled, VCC = 3.3 V, RSET = 7.08 kΩ, CTRL1 = 1, CTRL2 = 1 | |
| Shutdown Current | 5 | µA | |||
| Charge Pump Frequency | 1.5 | MHz | |||
| Charge Pump Mode Thresholds | 1.5× to 2×: 3.33 V | 2× to 1.5×: 3.36 V | V | ||
| Hysteresis | 40 | mV | |||
| ISET Pin LED Matching | 0.3% | % | ILED = 20 mA, VFB = 0.4 V | ||
| ISET Pin Voltage | 1.18 | V | |||
| ILED-to-ISET Ratio | 120 | ||||
| ILED-to-ISET Ratio Accuracy | ±5% | % | |||
| Charge Pump Output Resistance | 1.2 | 8.0 | Ω | 1× mode: 1.2 Ω, 1.5× mode: 3.5 Ω, 2× mode: 8.0 Ω | |
| LED Current | 20 | mA | |||
| PWM Frequency | 0.1 | 200 | kHz | ||
| Digital Input High | 0.7 VCC | V | |||
| Digital Input Low | 0.3 VCC | V | |||
| Input Leakage Current | 1 | µA | |||
| Charge Pump Power Efficiency | 88% | % | CTRL1 = 1, CTRL2 = 1, VCC = 3.4 V, VFB = 0.2 V, IFB = 20 mA | ||
| VOUT Ripple | 30 | mV | VCC = 3.6 V, ILED = 20 mA, all four LEDs enabled |
Key Features
- Brightness Control: The ADM8843 allows for brightness control of the white LEDs using either a digital PWM signal or a DC voltage applied to the VBRIGHT pin.
- High Current Accuracy: The device features four separate current sinks to sense each LED current individually, ensuring a typical matching performance of 0.3% for uniform brightness.
- Low Power Consumption: Fabricated using CMOS technology, the ADM8843 minimizes power consumption and includes soft start circuitry to limit in-rush current flow at power-up.
- Charge Pump Modes: The device operates in 1×, 1.5×, and 2× charge pump modes with thresholds and hysteresis to ensure stable operation.
- Shutdown and Control: The CTRL1 and CTRL2 digital input control pins manage the shutdown operation and the brightness of the main and sub displays.
- Compact Packaging: Available in a 16-lead lead frame chip scale package (LFCSP), making it suitable for space-constrained applications.
Applications
- Display Backlighting: Ideal for driving white LEDs in LCD display backlighting applications, including mobile devices, automotive displays, and industrial control panels.
- LED Lighting Systems: Suitable for various LED lighting systems that require precise current control and brightness adjustment.
- Portable Electronics: Used in portable electronics where low power consumption and compact design are essential.
Q & A
- What is the input voltage range for the ADM8843?
The input voltage range for the ADM8843 is from 2.6 V to 5.5 V.
- How does the ADM8843 control LED brightness?
The ADM8843 controls LED brightness using either a digital PWM signal or a DC voltage applied to the VBRIGHT pin.
- What is the typical current matching performance of the ADM8843?
The typical current matching performance is 0.3%.
- What are the charge pump modes available in the ADM8843?
The ADM8843 operates in 1×, 1.5×, and 2× charge pump modes.
- How does the ADM8843 manage shutdown and display control?
The shutdown and display control are managed by the CTRL1 and CTRL2 digital input control pins.
- What is the maximum operating temperature for the ADM8843?
The maximum operating temperature is +85°C.
- What is the package type for the ADM8843ACPZ-REEL7?
The package type is a 16-lead lead frame chip scale package (LFCSP).
- How does the ADM8843 ensure uniform brightness across LEDs?
The ADM8843 ensures uniform brightness by using four separate current sinks to sense each LED current individually.
- What is the charge pump power efficiency of the ADM8843?
The charge pump power efficiency is typically 88% under specified conditions.
- What is the VOUT ripple for the ADM8843?
The VOUT ripple is 30 mV under specified conditions.
