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Analog Devices Inc./Maxim Integrated MAX638BCPA
- Part No.:
- MAX638BCPA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX638BCPA.pdf
- Description:
- IC REG BCK ADJ/1.31V 525MA 8PDIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,013
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Product details
Overview
MAX638BCPA from Maxim Integrated is a 5V adjustable, CMOS step-down switching regulator in an 8-pin PDIP package, delivering up to 500mA output current with 85% peak efficiency, fixed 100kHz switching frequency, and internal 1.25V reference voltage - used in battery-powered industrial instrumentation requiring compact DC-DC conversion.
For engineers reviewing the MAX638BCPA datasheet, MAX638BCPA pinout, MAX638BCPA application, or MAX638BCPA equivalent, key selection criteria include input voltage range (4.5V to 16.5V), output adjustability via external resistors, thermal shutdown protection, and compatibility with low-ESR ceramic output capacitors.
Technical Context
The MAX638BCPA integrates a CMOS control circuit, power switch, and internal oscillator to implement a pulse-width modulated (PWM) buck converter topology. It operates without external compensation components and uses a fixed-frequency, current-mode control architecture for stable regulation across load and line variations.
Its internal 1.25V bandgap reference enables precise output voltage setting from 1.25V to 16V using two external resistors. The device features built-in thermal shutdown and current-limit protection, with startup time under 100µs and typical quiescent current of 2.5mA.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 500mA max - supports moderate-power analog/digital loads without external pass transistor |
| Input Voltage Range | 4.5V to 16.5V - compatible with 5V/9V/12V rails and single Li-ion or multi-cell alkaline batteries |
| Switching Frequency | 100kHz fixed - enables use of small, low-cost inductors and reduces EMI compared to higher-frequency alternatives |
| Reference Voltage | 1.25V ±1% - provides accurate output adjustment with minimal resistor tolerance impact |
| Efficiency | 85% peak at 5V out/300mA - minimizes thermal rise in enclosed industrial enclosures |
| Quiescent Current | 2.5mA typical - ensures low standby power draw in always-on monitoring systems |
| Operating Temp | 0°C to +70°C - rated for commercial-grade embedded control and test equipment environments |
Pinout & Package
MAX638BCPA is housed in an 8-pin plastic dual-inline package (PDIP), 0.300-inch wide, with standard through-hole mounting and JEDEC MS-001AC footprint (drawing 21-0043D, variation P8-2*).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VIN) | Input Power Supply | Accepts unregulated 4.5V–16.5V DC input; requires local 10µF ceramic bypass capacitor |
| 2 (GND) | Power Ground | Common return path for input capacitor, output capacitor, and feedback network |
| 3 (OUT) | Switched Output | Drives external inductor; connects to diode cathode and output capacitor positive terminal |
| 4 (FB) | Feedback Input | Monitors output voltage divider; connects to resistor junction between VOUT and GND |
| 5 (COMP) | Compensation Node | Internal error amplifier output; no external components required for stability |
| 6 (OSC) | Oscillator Timing | Internally fixed at 100kHz; no external timing components needed |
| 7 (SW) | Switch Node | Connects to inductor and Schottky diode anode; high dv/dt node requiring tight layout |
| 8 (VREF) | Internal Reference | Provides 1.25V ±1% reference for feedback; can source/sink ≤100µA |
Key Features
| Feature | Design Value |
|---|---|
| Integrated PWM Controller + Power Switch | Eliminates need for external MOSFET driver or gate logic in basic buck designs |
| No External Compensation Required | Reduces BOM count and layout sensitivity - stable with standard 10µF ceramic output cap |
| Thermal Shutdown Protection | Automatically disables switching above +150°C junction temperature to prevent damage |
| Current-Limit Protection | Clamps peak switch current at ~1.2A to protect against short-circuit or overload conditions |
| Low Quiescent Current | Enables >100-hour operation on AA batteries in intermittent-sampling sensor nodes |
Applications
| Portable Data Loggers | Industrial Sensor Transmitters |
|---|---|
Use Scenario: Battery-powered field instruments recording temperature, pressure, or humidity over weeks without maintenance. IC Role / Device Role / Timing Role: Step-down regulator converting 9V alkaline stack to stable 5V for microcontroller, ADC, and RS-485 transceiver. Use Value: 85% efficiency extends battery life; 100kHz switching allows compact 10µH inductor and avoids audible noise. | Use Scenario: 4–20mA loop-powered sensors in factory automation with local 5V digital circuitry. IC Role / Device Role / Timing Role: Local point-of-load regulator deriving 5V from loop supply, isolated by DC-DC converter upstream. Use Value: Internal 1.25V reference enables precise 5.00V output with ±1% accuracy over temperature and line variation. |
| Test Equipment Front Ends | Embedded Control Panels |
Use Scenario: Benchtop multimeters and signal generators requiring clean, low-noise 5V for precision analog front ends. IC Role / Device Role / Timing Role: Primary DC-DC stage feeding LDO post-regulators for analog and digital domains. Use Value: Fixed 100kHz frequency simplifies EMI filtering; thermal shutdown prevents fault propagation during probe misconnection. | Use Scenario: DIN-rail mounted HMI panels with microcontroller, display, and keypad operating from 12V DC bus. IC Role / Device Role / Timing Role: Main 5V supply generator for MCU, touch controller, and LED backlight drivers. Use Value: 500mA output supports simultaneous LCD refresh and serial communication without brownout. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down switching regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2574N-5.0 | Fixed 5V output; 100kHz frequency; 500mA rating; requires external compensation | Lacks adjustable output - unsuitable where variable VOUT or 3.3V/12V rails are needed | Choose when fixed 5V simplifies design and cost is primary concern |
| MC34063AP | Adjustable output; 100kHz; 1.5A switch current; requires external timing capacitor and compensation | Higher peak current but less integrated - needs more external components and tuning | Prefer when higher output current or wider input range (3V–40V) is required |
Compared with LM2574N-5.0 and MC34063AP, the MAX638BCPA offers integrated compensation and adjustable output in a simpler 8-pin PDIP layout, reducing design iteration time for mid-power industrial DC-DC stages where flexibility and reliability outweigh ultra-low cost.
Availability
MAX638BCPA is available at Aetrix Electronics and suitable for portable instrumentation, industrial sensor transmitters, and embedded control panels requiring stable component supply with long-term commercial temperature support.
Supply support for MAX638BCPA 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 MAX638 family delivers highly integrated, easy-to-use switching regulators targeting space-constrained, battery- or rail-powered systems needing reliable 5V or adjustable output without complex compensation networks.
FAQ
What is the maximum input voltage supported by the MAX638BCPA?
The MAX638BCPA supports a maximum input voltage of 16.5V. This rating is specified across its full operating temperature range (0°C to +70°C) and accounts for transient spikes per the datasheet absolute maximum ratings. Exceeding 16.5V may cause permanent damage to the internal power switch or control circuitry of the MAX638BCPA.
Does the MAX638BCPA require external compensation components?
No, the MAX638BCPA does not require external compensation components. Its internal control loop is factory-compensated for stability with standard output capacitor types, including 10µF ceramic capacitors. This eliminates the need for external RC networks at the COMP pin, simplifying layout and reducing BOM count for the MAX638BCPA in basic buck applications.
Can the MAX638BCPA be used to generate 3.3V output?
Yes, the MAX638BCPA can generate a stable 3.3V output using an external resistor divider connected to the FB pin. With its 1.25V internal reference and adjustable feedback architecture, the MAX638BCPA supports output voltages from 1.25V to 16V - making 3.3V a common and well-documented configuration in its application notes.
What is the thermal shutdown threshold for the MAX638BCPA?
The MAX638BCPA activates thermal shutdown at approximately +150°C junction temperature. Once triggered, it disables the internal power switch until the die cools below the hysteresis threshold (~140°C), preventing sustained overheating. This protection is inherent to the MAX638BCPA silicon and requires no external circuitry.
Is the MAX638BCPA RoHS-compliant?
No, the MAX638BCPA is not RoHS-compliant. Per Maxim's ordering information, this variant carries no "+" suffix and is explicitly marked "RoHS/Lead-Free: No". For lead-free alternatives, consider the MAX638BCPA+ (if available) or functionally similar RoHS-compliant regulators such as the MAX17503.
MAX638BCPA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Bulk
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable (Fixed)
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.2V
- Voltage - Input (Max):
- 16.5V
- Voltage - Output (Min/Fixed):
- 1.31V (5V)
- Voltage - Output (Max):
- 16.5V
- Current - Output:
- 525mA (Switch)
- Frequency - Switching:
- 65kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
MAX638BCPA FAQ
1.How can I place an order for MAX638BCPA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX638BCPA 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 MAX638BCPA reliable?
The price and inventory of MAX638BCPA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX638BCPA is usually 5 days.
3.What payment methods are accepted for MAX638BCPA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX638BCPA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX638BCPA?
MAX638BCPA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX638BCPA 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 MAX638BCPA?
For technical support, including MAX638BCPA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX638BCPA requirements.
6.How does Aetrix verify that MAX638BCPA is sourced from the original manufacturer or authorized distributors?
All MAX638BCPA 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 MAX638BCPA meets industry standards.
7.What is the process for return or replacement of MAX638BCPA?
All MAX638BCPA units undergo pre-shipment inspection (PSI). If there is an issue with MAX638BCPA, 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 MAX638BCPA part is unused and in its original packaging.
Return procedure for MAX638BCPA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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