Analog Devices Inc. ADP1109AN-5

Overview

ADP1109AN-5 from Analog Devices is a micropower fixed-output step-up DC-to-DC converter delivering 5 V at up to 100 mA from a 3 V input, operating at 120 kHz with 320 µA ground current and logic-controlled shutdown. It integrates an internal NPN power switch, 1.25 V reference, and comparator for feedback regulation-designed for battery-powered portable electronics requiring compact, low-quiescent-power voltage boosting.

For engineers reviewing the ADP1109AN-5 datasheet, ADP1109AN-5 pinout, ADP1109AN-5 application, or ADP1109AN-5 equivalent, key selection criteria include its fixed 5 V output accuracy (±5%), 2 V to 9 V input range, 8-lead PDIP package, and absence of external compensation-critical for space-constrained, low-noise, single-cell-to-5V conversion designs.

Technical Context

The ADP1109AN-5 uses a gated-oscillator architecture with internal 1.25 V reference and comparator hysteresis (8–14 mV) to regulate output without external frequency compensation. Its oscillator operates at 120 kHz (±17%) across input voltage (2–9 V) and temperature (0°C to +70°C), enabling use of small surface-mount inductors and capacitors.

Regulation relies on sensing voltage at the FB/SENSE pin (Pin 8), internally connected to laser-trimmed resistive divider for fixed 5 V output. Shutdown control (Pin 7) disables oscillation when pulled low, reducing quiescent current to 450 µA while maintaining regulated output hold-up via external components.

Key Specifications

Pinout & Package

ADP1109AN-5 is housed in an 8-lead plastic DIP (N-8) package with 0.300-inch width, through-hole mounting, and RoHS-compliant lead finish. Pin 1 is marked by notch or dot; pins 2, 5, and 6 are no-connect (NC) and must remain unconnected.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar step-up converter applications.

Compared with MAX630CPA+ and TPS61200DRCR, the ADP1109AN-5 offers the lowest quiescent current among fixed 5 V boosters and eliminates compensation components-making it optimal for cost-sensitive, space-constrained, battery-operated systems where output voltage stability and simplicity outweigh programmability or ultra-high efficiency.

Availability

ADP1109AN-5 is available at Aetrix Electronics and suitable for cellular telephones, portable instruments, and palmtop computers requiring stable component supply, long-term obsolescence management, and traceable sourcing for industrial and medical-grade designs.

Supply support for ADP1109AN-5 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets since 1965.

The ADP1109 series was designed specifically for micropower, low-component-count DC-DC boosting in portable battery-powered equipment-emphasizing simplicity, reliability, and minimal external part count over programmability or wide input flexibility.

FAQ

What is the maximum output current capability of the ADP1109AN-5?

The ADP1109AN-5 delivers up to 100 mA at 5 V when supplied from a 3 V input, as specified in the Typical Application section. Output current decreases with lower input voltage-e.g., ~50 mA at 2 V input-due to duty cycle and switch saturation limitations. Peak switch current is rated at 1.2 A, but sustained output is thermally limited by the 8-lead PDIP package's 300 mW dissipation rating.

Does the ADP1109AN-5 require external feedback resistors to set the 5 V output?

No. The ADP1109AN-5 incorporates laser-trimmed internal resistors that fix the output at 5.00 V ±5%. The FB/SENSE pin (Pin 8) connects directly to the output node-no external resistors are needed. This distinguishes it from the adjustable ADP1109A version, which requires an external R1/R2 divider.

Can the ADP1109AN-5 operate from a 2 V input source?

Yes. The ADP1109AN-5 supports input voltages from 2 V to 9 V, making it compatible with single-cell alkaline, NiMH, or partially discharged Li-ion batteries. At 2 V input, it delivers ~50 mA at 5 V (per Figure 3), with oscillator frequency and efficiency reduced relative to 3 V operation-but regulation remains stable per datasheet specifications.

What is the purpose of the NC pins (2, 5, 6) on the ADP1109AN-5?

Pins 2, 5, and 6 on the ADP1109AN-5 are designated "No Connection" and contain no internal circuitry. They must remain unconnected-neither routed nor soldered-to avoid parasitic coupling or mechanical stress on the die bond wires. This is explicitly confirmed in the Pin Function Descriptions and Pin Configurations sections of the datasheet.

How does the shutdown function affect power consumption in the ADP1109AN-5?

When the SHUTDOWN pin (Pin 7) is pulled low (<0.8 V), the ADP1109AN-5 disables its oscillator and reduces quiescent current to 450–590 µA-identical to its off-state draw. The internal reference and comparator remain active, allowing fast wake-up (<10 µs), but the power switch is fully disabled, eliminating switching losses and inductor current ripple.