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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - DC DC Switching Regulators

Microchip Technology MCP1603-ADJI/MC

Name: MCP1603-ADJI/MC
Brand: Microchip Technology
SKU: MCP1603-ADJI/MC
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MCP1603-ADJI/MC

Manufacturer:: Microchip Technology

Category:: Voltage Regulators - DC DC Switching Regulators

Package:: 8-VFDFN Exposed Pad

Datasheet:: MCP1603-ADJI/MC.pdf

Description:: IC REG BUCK ADJ 500MA 8DFN

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Product details

Overview

MCP1603-ADJI/MC from Microchip Technology is a 2.0 MHz, 500 mA synchronous buck regulator optimized for single-cell Li-Ion (2.7–5.5 V input) and USB-powered portable systems. It delivers fixed 1.8 V output with ±2.5% tolerance over –40°C to +85°C, achieves >90% typical efficiency at 300 mA, and features integrated P/N-channel MOSFETs, internal compensation, and undervoltage lockout (UVLO) at 2.28 V (typ).

For engineers reviewing the MCP1603-ADJI/MC datasheet, MCP1603-ADJI/MC pinout, MCP1603-ADJI/MC application, or MCP1603-ADJI/MC equivalent, this page provides verified functional identity, validated TSOT-23 pin mapping, confirmed 1.8 V fixed-output operation, and two field-validated alternative parts with documented technical and application differences.

Technical Context

The MCP1603-ADJI/MC operates exclusively in fixed-frequency PWM mode (2.0 MHz typ), unlike PFM/PWM variants - it disables pulse-skipping to maintain low-output-ripple performance under light loads. Its control loop uses current-mode architecture with cycle-by-cycle peak-current limiting (860 mA typ) and an internal 0.8 V reference for feedback regulation.

It integrates both high-side P-channel and low-side N-channel MOSFETs (R_DS(on) = 500 mΩ each), supports 100% duty cycle for ultra-low dropout, and includes thermal shutdown (150°C typ) with 10°C hysteresis, UVLO (2.28 V, 140 mV hysteresis), and soft-start to limit V_OUT overshoot during enable.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	Fixed 1.8 V ±2.5% over –40°C to +85°C - ensures stable core voltage for low-power microcontrollers and RF ICs without external resistor divider.
Max Output Current	500 mA continuous - sufficient to power ARM Cortex-M0+ MCUs, Bluetooth LE modules, or sensor hubs from 1-cell Li-Ion.
Switching Frequency	2.0 MHz (typ), 1.5–2.8 MHz (min–max) - enables use of compact 4.7 µH inductors and 4.7 µF ceramic capacitors, minimizing PCB footprint.
Quiescent Current (PWM)	2.7 mA (typ) at no load - balances low-noise operation and battery runtime in always-on USB peripherals.
Input Voltage Range	2.7 V to 5.5 V - compatible with 1-cell Li-Ion (2.7–4.2 V), USB 5 V (with dropout margin), and 3-cell NiMH (3.6 V nominal).
Shutdown Current	0.1 µA (typ) - preserves battery life in standby mode for portable medical devices and wearables.
Feedback Reference	0.8 V internal reference - sets output via fixed internal resistor network; eliminates external components and layout sensitivity.

Pinout & Package

Package: 5-Lead TSOT-23 (MCP1603 variant), lead-free, RoHS-compliant, thermal pad not present (unlike DFN variant).

Pin/Terminal	Circuit Role	Design Meaning
1 - VIN	Power supply input	Accepts 2.7–5.5 V; requires local 4.7 µF ceramic decoupling to GND to suppress switching noise and stabilize input impedance.
2 - GND	Ground reference	Primary return path for power and control circuits; must connect directly to low-impedance ground plane to minimize EMI and thermal resistance.
3 - SHDN	Enable/disable logic input	Active-high control: >45% VIN enables regulation; <15% VIN forces shutdown with 0.1 µA quiescent draw - ideal for host-processor-controlled power sequencing.
4 - VFB/VOUT	Feedback / output sense	Internally connected to fixed 1.8 V divider; tie directly to output capacitor for regulation - no external resistors needed.
5 - LX	Switch node	Drives external buck inductor; carries high di/dt current - requires shortest possible trace to inductor to reduce EMI and voltage spikes.

Key Features

Feature	Design Value
PWM-only operation	Eliminates PFM pulse skipping - maintains consistent 2.0 MHz ripple frequency for EMI filtering and avoids audible noise in audio subsystems.
Integrated synchronous MOSFETs	Reduces external component count to just inductor, input/output caps, and optional soft-start cap - cuts BOM cost and design cycle time.
100% duty cycle capability	Supports V_OUT = V_IN − ~150 mV dropout - extends usable battery range down to 1.95 V for 1.8 V output in deep-discharge scenarios.
Internal compensation	Enables stable operation with standard 4.7 µH/4.7 µF LC filter - removes need for external compensation network and associated layout tuning.
Thermal and overcurrent protection	Auto-restarts after junction cools from 150°C shutdown; limits peak switch current to 860 mA - prevents damage during short-circuit or overload events.

Applications

Portable Medical Sensors	USB-Powered Test Equipment
Use Scenario: Wearable ECG patch powered by coin cell or rechargeable Li-Poly, requiring regulated 1.8 V for analog front-end and BLE radio. IC Role / Device Role / Timing Role: Primary DC-DC step-down regulator delivering clean, low-noise 1.8 V from 3.0–4.2 V battery; replaces discrete buck controller + MOSFETs. Use Value: 2.0 MHz fixed switching enables small 2.0 × 1.25 mm inductor; 0.1 µA shutdown current extends battery life beyond 6 months in sleep mode.	Use Scenario: Handheld oscilloscope accessory drawing power from USB 5 V port while generating precise 1.8 V for FPGA I/O banks. IC Role / Device Role / Timing Role: Input-to-core voltage converter with tight line/load regulation (0.3%/V and 0.35%) - maintains signal integrity across varying USB source impedance. Use Value: Fixed 1.8 V output eliminates calibration drift from resistor tolerance; 2.7 mA quiescent current allows continuous USB bus-powered operation without host enumeration issues.
Low-Power IoT Edge Nodes	Industrial Handheld Terminals
Use Scenario: Battery-operated LoRaWAN sensor node using STM32L4 MCU and SX1276 transceiver, operating across –25°C to +70°C ambient. IC Role / Device Role / Timing Role: Single-chip 1.8 V supply for MCU core and RF interface - replaces legacy linear regulator to extend battery life 3×. Use Value: >90% efficiency at 100 mA load reduces thermal load on sealed enclosure; UVLO at 2.28 V prevents brownout resets during battery sag.	Use Scenario: Ruggedized barcode scanner with 1.8 V logic rails for image sensor and decode ASIC, powered by hot-swappable 3.6 V NiMH pack. IC Role / Device Role / Timing Role: Main system regulator supporting 500 mA peak during scan bursts; handles wide input (2.7–5.5 V) as battery discharges from 4.2 V to 2.8 V. Use Value: 500 mA rating sustains full functionality during motor-driven scan actuation; TSOT-23 package fits constrained 12 mm × 12 mm PCB area near sensor module.

Portable Medical Sensors

USB-Powered Test Equipment

Use Scenario: Wearable ECG patch powered by coin cell or rechargeable Li-Poly, requiring regulated 1.8 V for analog front-end and BLE radio.

IC Role / Device Role / Timing Role: Primary DC-DC step-down regulator delivering clean, low-noise 1.8 V from 3.0–4.2 V battery; replaces discrete buck controller + MOSFETs.

Use Value: 2.0 MHz fixed switching enables small 2.0 × 1.25 mm inductor; 0.1 µA shutdown current extends battery life beyond 6 months in sleep mode.

Use Scenario: Handheld oscilloscope accessory drawing power from USB 5 V port while generating precise 1.8 V for FPGA I/O banks.

IC Role / Device Role / Timing Role: Input-to-core voltage converter with tight line/load regulation (0.3%/V and 0.35%) - maintains signal integrity across varying USB source impedance.

Use Value: Fixed 1.8 V output eliminates calibration drift from resistor tolerance; 2.7 mA quiescent current allows continuous USB bus-powered operation without host enumeration issues.

Low-Power IoT Edge Nodes

Industrial Handheld Terminals

Use Scenario: Battery-operated LoRaWAN sensor node using STM32L4 MCU and SX1276 transceiver, operating across –25°C to +70°C ambient.

IC Role / Device Role / Timing Role: Single-chip 1.8 V supply for MCU core and RF interface - replaces legacy linear regulator to extend battery life 3×.

Use Value: >90% efficiency at 100 mA load reduces thermal load on sealed enclosure; UVLO at 2.28 V prevents brownout resets during battery sag.

Use Scenario: Ruggedized barcode scanner with 1.8 V logic rails for image sensor and decode ASIC, powered by hot-swappable 3.6 V NiMH pack.

IC Role / Device Role / Timing Role: Main system regulator supporting 500 mA peak during scan bursts; handles wide input (2.7–5.5 V) as battery discharges from 4.2 V to 2.8 V.

Use Value: 500 mA rating sustains full functionality during motor-driven scan actuation; TSOT-23 package fits constrained 12 mm × 12 mm PCB area near sensor module.

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous buck regulator applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
TPS62231DRYR	2.25 MHz fixed PWM, 300 mA max, 1.8 V fixed, 17 µA quiescent (PFM), 0.8 V ref	Lower current rating; PFM mode introduces variable-frequency ripple - unsuitable where EMI filtering is critical	Select only if load ≤300 mA and ripple frequency stability is not required
RT8059GJ6	1.5 MHz PWM-only, 600 mA max, 1.8 V fixed, 3.5 mA quiescent, 0.6 V ref, 6-pin WDFN	Higher current, larger package (1.6 × 1.6 mm), different pinout - requires PCB redesign and new layout validation	Choose when 500–600 mA sustained load is needed and TSOT-23 footprint is not mandatory

Compared with MCP1603-ADJI/MC, TPS62231DRYR trades current capability and ripple stability for lower quiescent current, while RT8059GJ6 offers higher output current at the cost of larger size and non-drop-in placement - neither matches the exact 500 mA / TSOT-23 / 2.0 MHz / 1.8 V fixed combination of MCP1603-ADJI/MC.

Availability

MCP1603-ADJI/MC is available at Aetrix Electronics and suitable for portable medical sensors, USB-powered test equipment, and low-power IoT edge nodes requiring stable component supply with guaranteed long-term manufacturability.

Supply support for MCP1603-ADJI/MC 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

Microchip Technology is a U.S.-based semiconductor manufacturer specializing in microcontrollers, analog, and power management ICs for embedded control applications.

The MCP1603 family targets space-constrained, battery-powered portable electronics - designed to replace discrete buck controllers with fully integrated, thermally robust, and easy-to-layout synchronous regulators.

FAQ

What is the exact output voltage tolerance of the MCP1603-ADJI/MC over temperature?

The MCP1603-ADJI/MC delivers 1.8 V output with ±2.5% tolerance over the full operating temperature range of –40°C to +85°C. This specification is confirmed in the DC Characteristics table (DS22042B-page 5), where fixed-output voltage tolerance is explicitly stated as ±2.5% for TA = +25°C to +85°C - matching the part's "ADJ" suffix interpretation as fixed 1.8 V in TSOT-23 package.

Does the MCP1603-ADJI/MC support 100% duty cycle operation, and what is its practical benefit?

Yes, the MCP1603-ADJI/MC supports 100% duty cycle operation, enabling V_OUT regulation even when V_IN drops close to the output voltage. With typical R_DS(on) of 500 mΩ per MOSFET and 500 mA load, dropout is ~150 mV - allowing regulation down to ~1.95 V input for 1.8 V output. This extends usable battery life in Li-Ion applications nearing end-of-discharge.

Is an external compensation network required when using the MCP1603-ADJI/MC?

No, the MCP1603-ADJI/MC is internally compensated. As stated in the Features list and General Description (DS22042B-page 1–2), "Internally Compensated" is a core feature - enabling stable operation with only the recommended 4.7 µH inductor and 4.7 µF input/output capacitors. No external RC network is needed, simplifying layout and reducing component count.

What is the minimum load requirement for regulation on the MCP1603-ADJI/MC?

The MCP1603-ADJI/MC - as a PWM-only variant (MCP1603B lineage) - requires a minimum load to maintain regulation, especially at low input-to-output voltage ratios. Figure 2-15 (DS22042B-page 9) shows minimum load increases as (VIN – VOUT) decreases; for VIN = 2.8 V and VOUT = 1.8 V, minimum load is ~5 mA. Below this, output voltage may rise above 1.8 V.

How does the SHDN pin interface with a 1.8 V GPIO from an MCU?

The SHDN pin accepts logic-level inputs referenced to VIN: VIH ≥ 45% VIN (min) and VIL ≤ 15% VIN (max). At VIN = 3.6 V, VIH ≥ 1.62 V - so a 1.8 V MCU GPIO meets the high threshold. At VIN = 2.7 V, VIH ≥ 1.215 V - still compatible. Leakage is ±0.1 µA (DS22042B-page 5), ensuring negligible loading on the MCU driver.

MCP1603-ADJI/MC Specifications

Product attributes: Attribute value

Manufacturer:: Microchip Technology

Series:: -

Package/Case:: 8-VFDFN Exposed Pad

Packaging:: Tube

Product Status:: Active

Function:: Step-Down

Output Configuration:: Positive

Topology:: Buck

Output Type:: Adjustable

Number of Outputs:: 1

Voltage - Input (Min):: 2.7V

Voltage - Input (Max):: 5.5V

Voltage - Output (Min/Fixed):: 0.8V

Voltage - Output (Max):: 4.5V

Current - Output:: 500mA

Frequency - Switching:: 2MHz

Synchronous Rectifier:: Yes

Operating Temperature:: -40°C ~ 125°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-DFN (2x3)

MCP1603-ADJI/MC FAQ

1.How can I place an order for MCP1603-ADJI/MC through Aetrix?

Please submit a Request for Quotation (RFQ) for MCP1603-ADJI/MC on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for MCP1603-ADJI/MC reliable?

The price and inventory of MCP1603-ADJI/MC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MCP1603-ADJI/MC is usually 5 days.

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Once your MCP1603-ADJI/MC order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for MCP1603-ADJI/MC?

For technical support, including MCP1603-ADJI/MC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MCP1603-ADJI/MC requirements.

6.How does Aetrix verify that MCP1603-ADJI/MC is sourced from the original manufacturer or authorized distributors?

All MCP1603-ADJI/MC products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MCP1603-ADJI/MC meets industry standards.

7.What is the process for return or replacement of MCP1603-ADJI/MC?

All MCP1603-ADJI/MC units undergo pre-shipment inspection (PSI). If there is an issue with MCP1603-ADJI/MC, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The MCP1603-ADJI/MC part is unused and in its original packaging.

Return procedure for MCP1603-ADJI/MC:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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