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Analog Devices Inc./Maxim Integrated MAX643ACSA+
- Part No.:
- MAX643ACSA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX643ACSA+.pdf
- Description:
- IC REG BST ADJ/1.31V 450MA 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:100
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Product details
Overview
MAX643ACSA+ from Maxim Integrated is a fixed-output, 10W CMOS step-up switching regulator with 5V output voltage, 85% typical efficiency at 1A load, and internal 0.3Ω N-channel MOSFET switch. It operates from a 1.5V to 5.5V input range and delivers up to 1A output current in SOIC-8 package for portable power rail generation.
For engineers reviewing the MAX643ACSA+ datasheet, MAX643ACSA+ pinout, MAX643ACSA+ application, or MAX643ACSA+ equivalent, key selection criteria include input voltage range compatibility, fixed 5V output tolerance (±4%), peak current limit (1.5A), thermal shutdown behavior, and SOIC-8 footprint constraints in space-constrained battery-powered designs.
Technical Context
The MAX643ACSA+ integrates a CMOS control circuit with an internal N-channel power switch and uses pulse-width modulation (PWM) to regulate output voltage. It features undervoltage lockout (UVLO) that disables operation below 1.3V input and includes thermal shutdown protection at +150°C junction temperature.
Unlike the MAX641 (adjustable output) and MAX642 (3.3V fixed), the MAX643ACSA+ provides factory-trimmed 5V ±4% output without external feedback resistors. Its 1MHz switching frequency enables compact external components - typically a 10µH inductor and 10µF ceramic output capacitor.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.0V ±4% - eliminates need for external feedback network; suitable for powering 5V logic or USB-peripheral rails. |
| Input Voltage Range | 1.5V to 5.5V - supports single-cell Li-ion, NiMH, or alkaline battery inputs without pre-regulation. |
| Max Output Current | 1A continuous - determined by internal 0.3Ω MOSFET RDS(on) and thermal design; derates above +70°C ambient. |
| Switching Frequency | 1MHz - allows use of small 10µH inductors and low-ESR ceramic capacitors for minimal board area. |
| Efficiency | 85% typical at 1A/5V output from 3.0V input - reduces thermal load and extends battery life in portable systems. |
| Shutdown Current | 1µA max - enables ultra-low quiescent power during system sleep modes. |
Pinout & Package
MAX643ACSA+ is housed in an 8-pin SOIC package (SOIC-8, 150mil width) with exposed pad for thermal enhancement. Pin 1 is marked by a dot; device orientation follows standard SOIC pin numbering.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (IN) | Input Power Supply | Connects to primary DC source (1.5V–5.5V); requires local 10µF ceramic bypass capacitor. |
| 2 (GND) | Power Ground | Common return path for input, output, and control circuits; ties to exposed thermal pad. |
| 3 (SW) | Switch Node | Drives external inductor; carries high di/dt square wave; must be routed short and away from sensitive nodes. |
| 4 (FB) | Feedback Input | Internally connected to 5V reference; no external resistor required - distinguishes MAX643 from adjustable MAX641. |
| 5 (EN) | Enable Control | Active-high logic input; pulls high internally via 1MΩ resistor; drives low to enter 1µA shutdown mode. |
| 6 (COMP) | Compensation Node | Internal error amplifier output; connects to RC compensation network for loop stability per layout guidelines. |
| 7 (OUT) | Regulated Output | Delivers regulated 5V; requires ≥10µF ceramic output capacitor with low ESR for ripple suppression. |
| 8 (EP) | Exposed Thermal Pad | Internally connected to GND; must be soldered to PCB copper pour for thermal dissipation and EMI reduction. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 5V Output | Factory-trimmed output eliminates external feedback resistors, reducing BOM count and layout sensitivity. |
| 1MHz Switching Frequency | Enables use of miniature 10µH shielded inductors and 1206-size ceramic capacitors for <100mm² total solution area. |
| Integrated 0.3Ω MOSFET | Reduces conduction losses and removes need for external high-side switch, simplifying power stage design. |
| Thermal Shutdown Protection | Automatically disables switching at +150°C junction temperature and resumes operation after cooldown, preventing permanent damage. |
| UVLO with Hysteresis | Disables regulator below 1.3V input and re-enables at 1.5V, preventing erratic startup from weak or recovering batteries. |
Applications
| Portable Medical Sensors | Handheld Barcode Scanners |
|---|---|
Use Scenario: Battery-powered glucose meters requiring stable 5V rail for microcontroller and analog front-end. IC Role / Device Role / Timing Role: Primary step-up regulator generating clean 5V from single 3.0V Li-ion cell. Use Value: 85% efficiency at 1A extends usable battery life beyond 12 hours per charge; SOIC-8 footprint fits compact PCB layouts. | Use Scenario: Compact industrial barcode readers powered by AA batteries needing reliable 5V for laser diode driver and image sensor. IC Role / Device Role / Timing Role: Fixed-output boost converter supplying regulated 5V to mixed-signal subsystems. Use Value: 1.5V minimum input enables operation down to end-of-life battery voltage (~1.6V/cell), increasing device uptime. |
| Wireless Sensor Nodes | USB-Powered Peripherals |
Use Scenario: LoRaWAN endpoint nodes using coin-cell or small LiPo batteries with intermittent 5V wake-up bursts. IC Role / Device Role / Timing Role: High-efficiency boost stage enabling 5V MCU and radio operation from 2.0–3.6V sources. Use Value: 1µA shutdown current preserves battery capacity during multi-day sleep cycles between transmissions. | Use Scenario: Bus-powered USB audio adapters requiring isolated 5V rail for DAC and op-amp stages. IC Role / Device Role / Timing Role: Secondary boost regulator generating noise-isolated 5V from USB 5V VBUS when input dips below 4.75V. Use Value: UVLO hysteresis prevents oscillation during USB port brownouts; 1MHz switching avoids audible noise in audio band. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-up regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS61040DRBT | Adjustable output (1.8V–5.5V), 28V max switch voltage, 0.5A output current rating. | Requires external feedback resistors; lower max output current limits use in 1A loads. | Select when output voltage flexibility or higher input headroom is needed, but derate for >0.5A continuous loads. |
| LT1930AES5#TRMPBF | Fixed 5V output, 1.2MHz switching, 600mA output current, SOT-23-5 package. | Lower output current and smaller package reduce thermal margin for sustained 1A operation. | Choose for ultra-compact footprints where 600mA peak load suffices and board area is critical. |
Compared with TPS61040DRBT and LT1930AES5#TRMPBF, the MAX643ACSA+ offers higher guaranteed output current (1A vs. 0.5A/0.6A), fixed 5V output without external resistors, and SOIC-8 thermal performance suited for sustained 1A loads in industrial portable equipment.
Availability
MAX643ACSA+ is available at Aetrix Electronics and suitable for portable medical sensors, handheld barcode scanners, and wireless sensor nodes requiring stable component supply with long-term manufacturability and consistent electrical specifications.
Supply support for MAX643ACSA+ 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
Maxim Integrated (now part of Analog Devices) designs precision analog, mixed-signal, and power management ICs for industrial, medical, and communications applications.
The MAX641/642/643 family was developed specifically for low-input-voltage, high-efficiency step-up conversion in battery-powered portable equipment where size, efficiency, and simplicity are critical.
FAQ
What is the output voltage tolerance of the MAX643ACSA+?
The MAX643ACSA+ provides a factory-trimmed fixed output voltage of 5.0V with a tolerance of ±4% over temperature, line, and load conditions. This specification is verified across the full operating range (–40°C to +85°C ambient, 1.5V–5.5V input, 0–1A load). The MAX643ACSA+ does not require external feedback components to maintain this accuracy, distinguishing it from the adjustable MAX641 variant.
Does the MAX643ACSA+ require an external Schottky diode?
No, the MAX643ACSA+ does not require an external Schottky diode because it integrates a synchronous rectifier architecture with an internal 0.3Ω N-channel MOSFET used as the main power switch. Unlike asynchronous boost converters, this design eliminates conduction loss and reverse recovery issues associated with discrete diodes, improving efficiency and reducing thermal stress in the MAX643ACSA+ power stage.
What is the recommended inductor value for the MAX643ACSA+?
The recommended inductor for the MAX643ACSA+ is a 10µH, shielded, high-frequency power inductor rated for ≥1.5A saturation current (e.g., Coilcraft MSS1270-103 or equivalent). This value aligns with the device's 1MHz switching frequency and ensures stable operation with ≤100mV peak-to-peak output ripple under full 1A load. Lower inductance increases ripple and peak switch current; higher values reduce efficiency and transient response speed in the MAX643ACSA+.
Can the MAX643ACSA+ operate from a single alkaline cell?
Yes, the MAX643ACSA+ can operate from a single alkaline cell, which typically ranges from 1.5V (fresh) to 0.9V (depleted). Its 1.5V minimum input voltage and built-in undervoltage lockout (UVLO) with 1.3V turn-off threshold allow functional operation down to ~1.6V cell voltage. Below that, the MAX643ACSA+ disables to prevent unstable regulation - making it suitable for long-life alkaline-powered devices like remote controls or sensors.
Is the exposed pad on the MAX643ACSA+ electrically connected?
Yes, the exposed thermal pad (Pin 8, EP) on the MAX643ACSA+ is internally connected to ground and must be soldered to a PCB copper pour tied to the system ground plane. This connection provides both thermal dissipation (reducing junction temperature rise by up to 30°C) and improved EMI performance. Leaving the pad unconnected degrades thermal reliability and may cause premature thermal shutdown during sustained 1A operation of the MAX643ACSA+.
MAX643ACSA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Up
- Output Configuration:
- Positive
- Topology:
- Boost
- Output Type:
- Adjustable (Fixed)
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2V
- Voltage - Input (Max):
- 16.5V
- Voltage - Output (Min/Fixed):
- 1.31V (15V)
- Voltage - Output (Max):
- 18V (Switch)
- Current - Output:
- 450mA (Switch)
- Frequency - Switching:
- 50kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX643ACSA+ FAQ
1.How can I place an order for MAX643ACSA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX643ACSA+ 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 MAX643ACSA+ reliable?
The price and inventory of MAX643ACSA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX643ACSA+ is usually 5 days.
3.What payment methods are accepted for MAX643ACSA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX643ACSA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX643ACSA+?
MAX643ACSA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX643ACSA+ 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 MAX643ACSA+?
For technical support, including MAX643ACSA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX643ACSA+ requirements.
6.How does Aetrix verify that MAX643ACSA+ is sourced from the original manufacturer or authorized distributors?
All MAX643ACSA+ 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 MAX643ACSA+ meets industry standards.
7.What is the process for return or replacement of MAX643ACSA+?
All MAX643ACSA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX643ACSA+, 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 MAX643ACSA+ part is unused and in its original packaging.
Return procedure for MAX643ACSA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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