Analog Devices Inc. LTC1144CS8#TRPBF

LTC1144CS8#TRPBF Charge Pump Switching Regulator Product Summary by Analog Devices Inc.

The LTC1144CS8#TRPBF, produced by Analog Devices Inc., is a high-performance charge pump switching regulator IC engineered to deliver flexible voltage conversion for a range of electronic systems. Housed in an 8-lead SOIC package (0.154", 3.90mm width), this monolithic CMOS device operates as a ratiometric voltage converter, capable of producing either positive or negative output voltages based on its input configuration. The device supports a single output with a sourcing capability of up to 50mA and targets applications requiring specialized voltage rails, particularly where compact regulation and minimal external components are desirable.

Main Features and Functions of LTC1144CS8#TRPBF

Engineers evaluating the LTC1144CS8#TRPBF will find several standout attributes that support robust and versatile design:

Wide operating supply voltage range: 2V to 18V, enabling use from portable battery systems to higher-voltage industrial rails.

Output configurations: Generates -Vin, 2Vin, or Vin/2 outputs, accommodating both positive and negative voltage conversions with minimal design complexity.

High efficiency: 99.9% typical voltage conversion efficiency and 93% typical power conversion efficiency, vital for applications sensitive to power loss.

Low output resistance: Typical values ranging from 56Ω at 15V and 10kHz operation, ensuring strong voltage regulation under load.

Power-saving shutdown mode: Via SHDN pin, quiescent current drops to 8μA when not active, an important consideration for battery-powered or low-power applications.

Flexible switching frequency: Internal oscillator runs at 10kHz but can be accelerated to higher frequencies via the boost pin, or externally clocked for frequency optimization.

Minimal external components: Requires only two non-critical capacitors for charge pump operation, reducing board space and design complexity.

Temperature range: Rated for 0°C to 70°C, the LTC1144CS8#TRPBF is suitable for most commercial environments.

Electrical Specifications of LTC1144CS8#TRPBF

For technical selection, understanding core electrical parameters is essential:

Supply Voltage Range: 2V to 18V, supporting varied infrastructure requirements.

Output Current: Up to 50mA, ideal for low to moderate load regulation tasks.

Switching Frequency: 4kHz to 10kHz internally, with capacity for higher speeds via boost pin (up to 10x).

Quiescent Current: 1.1mA typical in standard operation; just 8μA in shutdown mode.

Output Resistance: 56Ω typical at 15V and 10kHz, scaling to 250Ω at 5V/4kHz, ensuring predictable voltage drop under load.

Operating Temperature: 0°C to 70°C (LTC1144CS8#TRPBF variant).

Compliance: ROHS3 compliant, REACH unaffected, MSL1 rating for ease of handling in manufacturing.

LTC1144CS8#TRPBF Pinout Diagram and Functionality Overview

A clear understanding of pin assignments is crucial for correct PCB layout and performance. The LTC1144CS8#TRPBF features the following pinout:

Boost: Tie high to raise internal oscillator frequency by factor of ten.

CAP+: Positive terminal for pump capacitor.

GND: Device ground reference.

CAP-: Negative terminal for pump capacitor.

VOUT: Voltage output of the converter.

SHDN: Shutdown pin; low logic disables and powers down device.

OSC: Oscillator input; external clock can drive this pin, or an external capacitor can lower frequency.

V+: Main input voltage supply.

Functional descriptions clarify that the boost pin increases frequency to reduce ripple and output impedance. The SHDN pin allows for dynamic power management, while OSC and CAP+/- manage timing and charge transfer.

Principle of Operation and Application Insights for LTC1144CS8#TRPBF

The LTC1144CS8#TRPBF leverages a switched-capacitor voltage converter architecture. At its core, charge is transferred between capacitors via internal MOSFET switches, governed by an onboard oscillator. Charge pump operation alternates capacitor charge/discharge cycles between the input and output rails, producing either inverted or doubled output voltages. The internal divide-by-two logic and oscillator are designed to minimize losses and optimize efficiency.

The effective output impedance is determined principally by the equation Requiv = 1/(f × C1), where 'f' is the frequency and 'C1' the pump capacitance. This formula underscores the engineering trade-off between frequency (controlled via boost/OSC pins), capacitance (size and type selection), and the resulting regulation performance under varying load conditions.

Performance Data and Common Usage Examples of LTC1144CS8#TRPBF

Performance characterization is available across multiple application-relevant metrics:

Output voltage vs. load current: Exhibits stable voltage conversion with predictable drop-off as current approaches 50mA.

Output resistance: Demonstrates low resistance at optimal frequency/capacitance settings, with clear data showing effect of supply voltage, frequency, and ambient temperature.

Power conversion efficiency: Maintains >90% efficiency under typical load, decreasing at extreme frequencies or loads.

Ripple voltage: Low ripple at recommended capacitance and frequency, with data available for multiple configurations to inform design trade-offs.

Supply current: Minimal draw in low-load and shutdown modes, supporting battery longevity.

Application circuit examples provided include negative voltage conversion (e.g., +15V to –15V), voltage doubling using external diodes, ultra-precision voltage division for analog systems, and battery splitters to generate symmetric rails from a single supply. These examples illustrate typical engineering deployments, with data confirming device behavior under real-world conditions.

Selecting Capacitors and External Parts for LTC1144CS8#TRPBF

External capacitors C1 and C2 are required for proper charge pump operation, serving as both the transfer and storage elements. Selection criteria:

Value: 10μF commonly recommended for standard applications; larger capacitance lowers output impedance and ripple but increases physical size.

Tolerance and matching: Not critical; aluminum or tantalum electrolytics are generally suitable.

Capacitance on OSC pin: Adding external capacitance slows oscillator, increasing output impedance but may help noise-sensitive applications.

Designers must balance footprint, cost, and performance by adjusting capacitor values and types suited to their environment.

Engineering Use Cases for LTC1144CS8#TRPBF

Common engineering scenarios include:

Generating ±15V from a single supply for analog signal processing or OP-AMP rails.

Supplying inexpensive negative voltages to data acquisition or instrumentation systems.

Upgrading legacy designs based on LTC1044 or 7660 for higher voltage/power requirements.

Power supply division/multiplication in battery or automotive environments.

In each scenario, the LTC1144CS8#TRPBF delivers value through simplicity, high efficiency, and flexible voltage generation. Key considerations include load current limitations (50mA max), output impedance effects on voltage stability, and frequency optimization for ripple control.

Alternative or Equivalent Devices for LTC1144CS8#TRPBF

When evaluating alternatives, engineers may consider the following models:

LTC1044 series: For lower supply voltage or legacy compatibility; lower current and voltage range compared to LTC1144CS8#TRPBF.

ICL7660 series: A standard industry alternative for small current negative voltage generation, albeit with lower voltage/current handling.

LTC1144IN8#PBF/LTC1144CN8#TRPBF: Alternate package or extended temperature variants of the LTC1144 family, retaining identical electrical performance.

Selection among these depends on system voltage, current requirements, package preference, and operating temperature range.

Conclusion

: Choosing LTC1144CS8#TRPBF for efficient voltage conversion

The LTC1144CS8#TRPBF charge pump switching regulator from Analog Devices Inc. stands out as a flexible, efficient, and compact solution for engineers seeking robust voltage inversion, doubling, or division with minimal design overhead. The combination of broad supply range, high efficiency, programmable frequency, and simplified external component requirements make it an optimal choice for a wide range of analog, mixed-signal, and embedded designs. By understanding its functional capabilities, application theory, and integration considerations, product selection engineers and procurement professionals can confidently specify the LTC1144CS8#TRPBF to meet stringent voltage conversion needs in advanced electronic systems.