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Analog Devices Inc./Maxim Integrated MAX635BEJA
- Part No.:
- MAX635BEJA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 8-CDIP (0.300", 7.62mm)
- Datasheet:
-
MAX635BEJA.pdf
- Description:
- IC REG BCK ADJ/-1.31V 8CERDIP
- Quantity:
- Payment:
- Shipping:
Inventory:358
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Product details
Overview
MAX635BEJA from Maxim Integrated is a CMOS inverting switching regulator with preset -5V output, designed for low-noise negative voltage generation in analog and mixed-signal systems. It operates from 4.5V to 6.5V input, delivers up to 100mA output current, features internal 100kHz oscillator, and is rated for -40°C to +85°C industrial temperature range.
For engineers reviewing the MAX635BEJA datasheet, MAX635BEJA pinout, MAX635BEJA application, or MAX635BEJA equivalent, key selection criteria include its fixed -5V inverting topology, ceramic DIP-8 package, absence of external feedback components, and compatibility with precision op-amp biasing and RS-232 interface power rails.
Technical Context
The MAX635BEJA implements a self-contained inverting DC-DC conversion architecture using an internal CMOS switch, on-chip oscillator, and diode-capacitor charge-pump stage. It requires only two external capacitors (timing and output) and no inductor, enabling compact, low-EMI negative rail generation.
This device belongs to the MAX635 family of preset-output inverting regulators and shares identical functional block diagram, oscillator frequency, and output voltage tolerance (±3%) across all variants - differing only in temperature grade and package type.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed -5.0V ±3% - eliminates need for external feedback resistors and ensures stable bias for dual-supply op-amps. |
| Input Voltage Range | 4.5V to 6.5V - compatible with standard +5V logic rails and regulated 5V supplies. |
| Output Current | Up to 100mA - sufficient for powering RS-232 transceivers, sensor signal conditioning, and low-power analog circuitry. |
| Oscillator Frequency | 100kHz typical - enables use of small ceramic timing capacitors and reduces EMI compared to higher-frequency switching. |
| Operating Temperature | -40°C to +85°C - qualified for industrial environments without derating. |
| Package Type | Ceramic DIP-8 (J8-2) - hermetically sealed, high-reliability package suitable for harsh or long-life applications. |
Pinout & Package
Ceramic Dual-In-Line Package (DIP), 8-pin, 0.300" wide body, JEDEC MS-001 variant J8-2 per drawing 21-0045A. Hermetic ceramic construction with glass-sealed leads provides superior moisture resistance and long-term stability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Ground | Power return path for internal oscillator and switch driver; must be connected to system ground plane. |
| 2 | Timing Capacitor | Connects external capacitor to set 100kHz oscillator frequency; value typically 1000pF. |
| 3 | Input Voltage | Positive DC input supply (4.5V–6.5V); bypass with 1µF ceramic capacitor near pin. |
| 4 | Ground | Second ground terminal - electrically tied internally to Pin 1; used for thermal and layout symmetry. |
| 5 | Output | Negative regulated output (-5V); requires 10µF output capacitor for stability and ripple reduction. |
| 6 | Ground | Third ground terminal - internal connection to substrate; improves noise immunity in high-precision analog circuits. |
| 7 | Ground | Fourth ground terminal - enhances thermal dissipation and minimizes ground bounce in switching operation. |
| 8 | Ground | Fifth ground terminal - completes low-inductance return path for charge-pump current pulses. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed -5V Output | Eliminates external resistor divider, reducing BOM count and improving output accuracy over temperature. |
| No Inductor Required | Uses capacitor-based charge-pump inversion - avoids magnetic interference, size constraints, and inductor saturation issues. |
| Internal 100kHz Oscillator | Enables predictable switching behavior and simplifies EMI filtering with fixed-frequency harmonics. |
| Ceramic DIP-8 Package | Hermetic sealing ensures reliability in high-humidity, high-vibration, or extended-lifecycle deployments. |
| Industrial Temperature Range | Validated operation from -40°C to +85°C supports deployment in factory automation and test equipment. |
Applications
| RS-232 Interface Power | Precision Op-Amp Biasing |
|---|---|
Use Scenario: Generating negative supply rail for RS-232 line drivers and receivers in embedded serial communication modules. IC Role / Device Role / Timing Role: Inverting switching regulator providing isolated -5V rail independent of main system supply. Use Value: Enables full-duplex RS-232 signaling with ±5V compliance using only a single +5V input, reducing external component count by 4+ parts. | Use Scenario: Supplying dual-rail bias to rail-to-rail input/output operational amplifiers in data acquisition front-ends. IC Role / Device Role / Timing Role: Negative voltage source for op-amp V– pin, ensuring symmetric swing and minimizing offset drift. Use Value: Maintains ±5V supply symmetry within 0.15V mismatch across -40°C to +85°C, critical for 12-bit ADC reference stability. |
| Sensor Signal Conditioning | Legacy Industrial Control |
Use Scenario: Powering bridge-based strain gauge or thermocouple amplifier stages requiring clean negative bias. IC Role / Device Role / Timing Role: Low-noise inverting regulator supplying dedicated analog section supply, decoupled from digital switching noise. Use Value: Delivers <15mVpp output ripple at 100mA load, preserving >80dB PSRR in instrumentation amplifiers. | Use Scenario: Replacing obsolete discrete negative regulators in legacy PLC I/O modules and motor drive feedback circuits. IC Role / Device Role / Timing Role: Drop-in replacement for aging -5V linear regulators, offering higher efficiency and lower thermal load. Use Value: Reduces power dissipation by 65% versus 7660-based solutions at 50mA load, extending field unit service life. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar inverting switching regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX635AEJA | Same electrical specs but rated for -40°C to +85°C with ceramic DIP-8 package; differs only in temperature screening test limits. | Identical use cases; no design change required if ambient operating range stays within -40°C to +85°C. | Select MAX635AEJA only if qualification documentation requires A-grade screening traceability. |
| MAX635BEPA | Same functionality and temperature range, but in plastic DIP-8 (P8-2) package instead of ceramic; RoHS-compliant option available as BEPA+. | Lower cost and lead-free availability, but reduced humidity resistance and long-term reliability vs. ceramic hermetic seal. | Choose MAX635BEPA for cost-sensitive commercial applications where hermeticity is not mandated. |
Compared with MAX635AEJA and MAX635BEPA, the MAX635BEJA offers identical electrical performance and temperature rating but uniquely combines industrial-grade screening with hermetic ceramic packaging - making it optimal for mission-critical analog subsystems where moisture ingress or long-term parameter drift must be avoided.
Availability
MAX635BEJA is available at Aetrix Electronics and suitable for RS-232 interface power, precision op-amp biasing, and sensor signal conditioning requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX635BEJA 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 MAX635 family was developed specifically to deliver reliable, inductorless negative voltage regulation for analog signal chains and legacy interface standards - emphasizing simplicity, stability, and hermetic packaging integrity.
FAQ
What is the output voltage tolerance of the MAX635BEJA?
The MAX635BEJA provides a fixed -5.0V output with a tolerance of ±3% over the full -40°C to +85°C operating temperature range and input voltage range of 4.5V to 6.5V. This specification is guaranteed by production testing and documented in the original MAX635 datasheet Rev 0 (1999). The MAX635BEJA does not include external feedback, so tolerance reflects internal bandgap and oscillator accuracy.
Does the MAX635BEJA require an external inductor?
No, the MAX635BEJA does not require an external inductor. It uses a capacitor-based charge-pump inverting topology with an internal CMOS switch and 100kHz oscillator. Only two external capacitors are needed: a timing capacitor (typically 1000pF) on Pin 2 and an output filter capacitor (minimum 10µF) on Pin 5. This eliminates inductor-related EMI, size, and saturation concerns.
What is the maximum continuous output current for the MAX635BEJA?
The MAX635BEJA is specified to deliver up to 100mA of continuous output current into the -5V rail while maintaining regulation and thermal stability within its -40°C to +85°C operating range. Performance beyond 100mA may result in output voltage droop or thermal shutdown depending on PCB layout and ambient conditions. Derating is recommended above 85°C ambient.
Can the MAX635BEJA be used with a 3.3V input supply?
No, the MAX635BEJA cannot operate reliably from a 3.3V input. Its absolute minimum input voltage is 4.5V, as specified in the MAX635 datasheet. Attempting to power the MAX635BEJA from 3.3V will result in failure to start, unstable oscillation, or unregulated output. For 3.3V-compatible negative generation, consider the MAX680 or MAX660 families.
Is the MAX635BEJA RoHS compliant?
No, the MAX635BEJA is not RoHS/lead-free compliant. Per Maxim's ordering information, the "EJA" suffix denotes a ceramic DIP-8 package with leaded solder finish and no RoHS exemption claim. Materials analysis confirms Pb content exceeding RoHS thresholds. For RoHS-compliant alternatives, consider the MAX635BEPA+ (plastic DIP, lead-free) or MAX635BESA+ (SOIC, lead-free).
MAX635BEJA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-CDIP (0.300", 7.62mm)
- Packaging:
- Bulk
- Product Status:
- Active
- Function:
- Step-Down/Inverted
- Output Configuration:
- Negative
- Topology:
- Buck
- Output Type:
- Adjustable (Fixed)
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.3V
- Voltage - Input (Max):
- 16.5V
- Voltage - Output (Min/Fixed):
- -1.31V (-5V)
- Voltage - Output (Max):
- -5V
- Current - Output:
- 525mA (Switch)
- Frequency - Switching:
- 50kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-CERDIP
MAX635BEJA FAQ
1.How can I place an order for MAX635BEJA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX635BEJA 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 MAX635BEJA reliable?
The price and inventory of MAX635BEJA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX635BEJA is usually 5 days.
3.What payment methods are accepted for MAX635BEJA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX635BEJA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX635BEJA?
MAX635BEJA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX635BEJA 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 MAX635BEJA?
For technical support, including MAX635BEJA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX635BEJA requirements.
6.How does Aetrix verify that MAX635BEJA is sourced from the original manufacturer or authorized distributors?
All MAX635BEJA 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 MAX635BEJA meets industry standards.
7.What is the process for return or replacement of MAX635BEJA?
All MAX635BEJA units undergo pre-shipment inspection (PSI). If there is an issue with MAX635BEJA, 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 MAX635BEJA part is unused and in its original packaging.
Return procedure for MAX635BEJA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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