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Analog Devices Inc./Maxim Integrated MAX639EPA+
- Part No.:
- MAX639EPA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX639EPA+.pdf
- Description:
- IC REG BUCK ADJ/1.3V 225MA 8PDIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,917
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Product details
Overview
MAX639EPA+ from Maxim Integrated is a 5V fixed-output, high-efficiency step-down DC-DC switching regulator with internal 1A PMOS power switch, 10µA quiescent current, and -40°C to +85°C operating temperature range. It delivers up to 225mA output current from 4V–11.5V input, targeting battery-powered portable instruments requiring stable low-noise 5V rail generation.
For engineers reviewing the MAX639EPA+ datasheet, MAX639EPA+ pinout, MAX639EPA+ application, or MAX639EPA+ equivalent, key selection criteria include its PFM control scheme for ultra-low IQ operation, integrated low-battery detection (LBI/LBO), adjustable vs. fixed-output configuration flexibility, and compatibility with standard 100µH inductors and Schottky diodes in compact DIP-8 layouts.
Technical Context
The MAX639EPA+ implements a current-limiting pulse-frequency-modulated (PFM) control architecture that dynamically adjusts switching frequency and duty cycle to maintain constant peak inductor current (IPEAK = 50µs × V / L), enabling high efficiency across light-to-heavy loads without external compensation. Its error comparator drives a variable-frequency oscillator only when output voltage dips below regulation threshold.
It integrates a 1.28V bandgap reference for both feedback (VFB) and low-battery detection (LBI), supports shutdown via active-low SHDN pin with 0.8V–1.15V threshold, and maintains LBO functionality even during shutdown. The LX pin drives an external inductor directly, while VOUT is internally regulated to 5.00V ±2% over temperature and line.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.00V ±2% (guaranteed by correlation to on-resistance, timing, and trip-point measurements) |
| Input Voltage Range | 4.0V to 11.5V - supports 9V battery, dual-AA, or industrial 5V/12V rails with margin |
| Max Output Current | 225mA at VIN ≥ 6V with 100µH inductor - sufficient for microcontrollers, sensors, and logic |
| Quiescent Supply Current | 10µA typical - enables >1-year battery life in always-on portable devices |
| Efficiency | 89% typical at 100mA load, 9V input - exceeds linear regulators by >4× at medium loads |
| Low-Battery Threshold | 1.28V on LBI pin - configurable via external resistor divider for system-level brownout detection |
| Shutdown Threshold | 0.80V to 1.15V on SHDN pin - ensures clean disable with standard logic-level signals |
Pinout & Package
MAX639EPA+ uses an 8-pin plastic DIP package (0.300" wide) with through-hole mounting, rated for -40°C to +85°C operation and 727mW continuous power dissipation at +70°C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VOUT | Regulated output sense node | Internally connected to voltage divider; must be tied directly to output capacitor for stable 5V regulation |
| LBO | Open-drain low-battery output | Sinks up to 10mA when LBI < 1.28V; requires external pull-up for system alert signaling |
| LBI | Low-battery input comparator | Monitors external voltage divider; remains active during shutdown for battery monitoring |
| GND | Power and signal reference ground | Must be star-connected with CIN, COUT, and diode anode to minimize ground bounce |
| LX | PMOS switch drain terminal | Drives external inductor; handles 1A peak current and fast dI/dt transitions |
| V+ | Positive supply input | Accepts 4V–11.5V; must be bypassed with ≥33µF low-ESR capacitor near IC |
| VFB | Dual-mode feedback pin | Grounded for fixed 5V output; connected to external divider for adjustable outputs (1.3V–VIN) |
| SHDN | Active-low shutdown control | Pulled below 0.8V disables LX; tied to V+ for always-on operation |
Key Features
| Feature | Design Value |
|---|---|
| PFM control architecture | Enables 10µA quiescent current and >85% efficiency at 1mA load - critical for battery longevity |
| Integrated 1A PMOS switch | Eliminates need for external MOSFET and gate driver - reduces BOM count and layout area |
| Low-battery detection with LBI/LBO | Provides system-level battery monitoring without additional comparators or references |
| Fixed 5V or adjustable output | Supports drop-in 5V replacement or custom voltages (1.3V–VIN) using two resistors |
| Startup time & transient response | Typical 10ms startup to 5V at 100mA; <100mV load transient deviation with 100µH/1N5817 design |
Applications
| 9V Battery to 5V Conversion | High-Efficiency Linear Regulator Replacement |
|---|---|
|
Use Scenario: Powering microcontroller-based handheld terminals from a single 9V alkaline battery. IC Role / Device Role / Timing Role: Primary step-down regulator generating stable 5V rail with dynamic load handling up to 225mA. Use Value: Extends battery life >3× versus 78L05 due to 10µA IQ and PFM efficiency down to µA loads. |
Use Scenario: Replacing obsolete 7805 linear regulators in industrial sensor nodes where thermal derating limits output current. IC Role / Device Role / Timing Role: Efficient 5V DC-DC converter eliminating heatsink requirement and enabling higher ambient temperature operation. Use Value: Delivers full 225mA at +85°C without thermal shutdown, unlike linear regulators limited to ~100mA under same conditions. |
| Portable Instruments | 5V-to-3.3V Converter Interface |
|
Use Scenario: Providing main 5V supply for portable multimeters and data loggers with LCD and ADC subsystems. IC Role / Device Role / Timing Role: Core power management IC with integrated low-battery warning (LBI/LBO) for user alerts. Use Value: Single-chip solution reduces component count by 4+ parts (regulator, comparator, reference, pull-up) versus discrete alternatives. |
Use Scenario: Generating clean 3.3V logic rail from existing 5V system bus in mixed-voltage embedded designs. IC Role / Device Role / Timing Role: Secondary regulator stage feeding FPGA I/O banks or low-voltage microcontrollers. Use Value: Achieves <15mV output ripple with 100µF aluminum + 0.1µF ceramic output filter - meets 3.3V digital noise budgets. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down DC-DC converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX640EPA+ | Fixed 3.3V output; identical pinout, package, and PFM architecture; 10µA IQ, 225mA capability | Used where 3.3V logic rail required instead of 5V - no circuit redesign needed beyond output capacitor | Select MAX640EPA+ when system requires 3.3V instead of 5V; shares same layout and external components |
| TPS62231DRVR | 3MHz PWM converter; 22µA IQ; 300mA output; 2mm × 2mm WSON package; requires external compensation | Better suited for space-constrained PCBs and noise-sensitive analog circuits due to fixed-frequency operation | Choose TPS62231DRVR for high-density layouts or EMI-critical applications; not pin-compatible with MAX639EPA+ |
Compared with MAX640EPA+, MAX639EPA+ provides higher output voltage for legacy 5V peripherals; compared with TPS62231DRVR, it offers lower IQ and simpler design but lacks fixed-frequency EMI control and smaller footprint.
Availability
MAX639EPA+ is available at Aetrix Electronics and suitable for portable instrumentation, battery-powered handheld terminals, and industrial sensor nodes requiring stable component supply with extended temperature support and long-term obsolescence management.
Supply support for MAX639EPA+ 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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, automotive, and communications markets.
The MAX639/MAX640/MAX653 family was designed specifically for ultra-low-power, high-efficiency DC-DC conversion in portable and battery-operated systems where quiescent current and simplicity are critical.
FAQ
What is the guaranteed output voltage tolerance for MAX639EPA+?
The MAX639EPA+ guarantees 5.00V output with ±2% tolerance over full temperature (-40°C to +85°C) and line (4V–11.5V) ranges, verified by correlation to switch on-resistance, on/off times, and output voltage trip points - not just initial characterization.
Can MAX639EPA+ operate with input voltage below 4V?
No. The absolute minimum input voltage for MAX639EPA+ is 4.0V per Absolute Maximum Ratings and Electrical Characteristics tables; operation below this risks failure to regulate or undefined behavior. For sub-4V inputs, consider MAX662 or other low-VIN buck regulators.
Does MAX639EPA+ require external compensation components?
No. The MAX639EPA+ uses a current-limiting PFM control scheme with internal compensation - no external capacitors or resistors are needed for stability, simplifying design and reducing bill-of-materials versus voltage-mode PWM regulators.
How does the low-battery detector function in shutdown mode?
The low-battery comparator remains fully active during shutdown: LBI continues monitoring external voltage, and LBO will sink current if LBI drops below 1.28V, enabling battery status awareness even when the main regulator is disabled - a key feature for sleep-mode systems.
What inductor value is recommended for maximum 225mA output with MAX639EPA+?
A 100µH inductor with ≥600mA saturation current rating is recommended for MAX639EPA+ to deliver full 225mA output; lower values risk saturation and reduced current capability, while higher values improve light-load efficiency but increase size and cost.
MAX639EPA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable (Fixed)
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4V
- Voltage - Input (Max):
- 11.5V
- Voltage - Output (Min/Fixed):
- 1.3V (5V)
- Voltage - Output (Max):
- 11.5V
- Current - Output:
- 225mA
- Frequency - Switching:
- -
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
MAX639EPA+ FAQ
1.How can I place an order for MAX639EPA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX639EPA+ 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 MAX639EPA+ reliable?
The price and inventory of MAX639EPA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX639EPA+ is usually 5 days.
3.What payment methods are accepted for MAX639EPA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX639EPA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX639EPA+?
MAX639EPA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX639EPA+ 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 MAX639EPA+?
For technical support, including MAX639EPA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX639EPA+ requirements.
6.How does Aetrix verify that MAX639EPA+ is sourced from the original manufacturer or authorized distributors?
All MAX639EPA+ 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 MAX639EPA+ meets industry standards.
7.What is the process for return or replacement of MAX639EPA+?
All MAX639EPA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX639EPA+, 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 MAX639EPA+ part is unused and in its original packaging.
Return procedure for MAX639EPA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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