**ADM8843ACPZ-REEL7: A Comprehensive Technical Overview of the Charge Pump DC-to-DC Converter**

The **ADM8843ACPZ-REEL7** from Analog Devices is a highly integrated, switched capacitor **voltage inverter** and **doubler** designed to provide regulated output voltages from a single input supply. This charge pump DC-to-DC converter is engineered for space-constrained, battery-powered portable electronics, where component count, efficiency, and footprint are paramount. Its ability to generate a negative supply rail from a positive input or double a positive input voltage makes it indispensable for applications like powering operational amplifiers, LCD displays, CCD sensors, and audio amplifiers.

**Architecture and Operating Modes**

At the core of the ADM8843 is a charge pump circuit, a topology that utilizes capacitors rather than inductors for energy storage and voltage conversion. This architecture eliminates the need for large, expensive, and EMI-prone inductors, resulting in a compact and simple solution. The device operates in three primary modes, selected via two logic control inputs (**PS0** and **PS1**):

1. **×1 Mode (Voltage Inverter):** The device generates a negative output voltage (**-VIN**) from the positive input supply. This is ideal for generating a simple negative rail.

2. **×2 Mode (Voltage Doubler):** The device generates a positive output voltage that is approximately twice the input voltage (**2×VIN**).

3. **×1.5 Mode (Voltage Tripler):** The device generates a positive output voltage that is approximately 1.5 times the input voltage (**1.5×VIN**). This mode offers a compromise between output current capability and voltage boost.

A key feature of the ADM8843 is its **internal low-dropout (LDO) linear regulator**. This post-regulator actively regulates the output voltage, ensuring a stable and precise supply regardless of variations in input voltage or load current. This sets it apart from simpler, unregulated charge pumps whose output voltage can sag significantly under load.

**Key Technical Specifications and Features**

* **Wide Input Voltage Range:** **2.5V to 5.5V**, making it compatible with common power sources like single-cell Li-ion batteries (3.0V to 4.2V), 3.3V system rails, and 5V supplies.

* **Precision Regulated Output:** The integrated LDO provides a highly stable output, available in fixed -5V, +5V, or +3.3V versions, as well as an adjustable option.

* **High Output Current:** Capable of delivering up to **150 mA** of output current, sufficient for a wide range of analog and mixed-signal components.

* **High Operating Frequency:** The device switches at a high **750 kHz**, allowing for the use of very small, low-value ceramic capacitors (typically 1µF). This minimizes the total solution size and cost.

* **Low Power Consumption:** Features a low quiescent current and an automatic **shutdown mode** (drawing <1µA) when enabled via a logic pin, drastically extending battery life in portable devices.

* **Minimal External Components:** Requires only three small ceramic capacitors (flying and reservoir capacitors) to form a complete DC-DC conversion solution.

* **Compact Package:** Housed in a space-saving **16-lead, 3mm × 3mm LFCSP (Lead Frame Chip Scale Package)**.

**Applications**

The combination of small size, high efficiency, and simplicity makes the ADM8843ACPZ-REEL7 a perfect fit for:

* Smartphones, Tablets, and Portable Media Players

* Portable Medical and Industrial Instruments

* USB-Powered Devices

* Generating Negative Supplies for Op-Amps and Data Converters

* Powering LCD Bias and Audio Amplifiers

**ICGOODFIND**

**ICGOODFIND:** The ADM8843ACPZ-REEL7 stands out as an exceptionally versatile and efficient component for power management design. Its **inductorless architecture** drastically simplifies PCB layout and reduces EMI, while its **integrated LDO regulator** ensures performance stability that unregulated charge pumps cannot match. For engineers developing compact, battery-sensitive portable applications requiring auxiliary positive or negative voltage rails, this device represents a superior, all-in-one power conversion solution.

**Keywords:**

1. **Charge Pump**

2. **Voltage Inverter**

3. **DC-DC Converter**

4. **Regulated Output**

5. **Portable Electronics**