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Analog Devices Inc./Maxim Integrated MAX757CSA+
- Part No.:
- MAX757CSA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX757CSA+.pdf
- Description:
- IC REG BOOST ADJ 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,754
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Product details
Overview
MAX757CSA+ from Maxim Integrated is an adjustable-output, CMOS step-up DC-DC switching regulator designed for low-input-voltage battery-powered systems. It operates down to 0.7V input, delivers 2.7V–5.5V output via external feedback (FB pin), achieves >87% efficiency at 200mA, and features 60µA quiescent current and 500kHz max switching frequency - used in glucose meters and portable data-collection equipment.
For engineers reviewing the MAX757CSA+ datasheet, MAX757CSA+ pinout, MAX757CSA+ application, or MAX757CSA+ equivalent, this page provides verified technical context, package mapping, real-world operating parameters, and validated alternative options for battery-powered step-up conversion designs requiring ultra-low start-up voltage and shutdown current.
Technical Context
The MAX757CSA+ integrates a 1A/0.5Ω N-channel power MOSFET, precision 1.25V reference (±1.5% over temperature), and low-battery detector (LBI/LBO) in a monolithic IC. Its constant-off-time pulse-frequency modulation (PFM) control enables self-oscillating operation without an external oscillator - peak switch current fixed at 1A ±0.2A, with switching frequency scaling from light-load minimum off-time (1µs) to up to 500kHz under load.
It uses bootstrapped internal supply derived from OUT, enabling operation even as input sags below 1V post-startup. The FB pin accepts external resistor divider for precise output setting (VOUT = 1.25V × (R1 + R2)/R2), while REF provides 250µA source / 20µA sink capability and remains active in shutdown mode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 0.7V min startup, 0.7V–5.5V operating - supports single-cell alkaline or NiMH batteries down to end-of-life voltage. |
| Output Voltage Range | 2.7V to 5.5V adjustable via FB pin - set by external resistor divider; no fixed-output variants required. |
| Efficiency | >87% typical at 200mA - reduces thermal stress and extends battery runtime in portable medical devices. |
| Quiescent Current | 60µA typical - minimizes standby drain in always-on battery systems like handheld diagnostics. |
| Shutdown Current | 20µA - maintains reference and LBI detector functionality while disabling SMPS, enabling wake-on-low-battery. |
| Switching Frequency | Up to 500kHz - allows use of compact 22µH surface-mount inductors (<5mm diameter) and reduces output filter size. |
| Reference Voltage | 1.25V ±1.5% over temperature - stable feedback reference for accurate output regulation across industrial temperature range. |
Pinout & Package
MAX757CSA+ is housed in an 8-pin SO (Small Outline) package, 3.9mm × 4.9mm body, 1.27mm pitch, JEDEC MS-012AC compliant. Pin 7 (GND) must be soldered directly to a low-impedance ground plane to minimize noise and maximize efficiency.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 SHDN | Shutdown control input | Active-low logic input; disables SMPS but keeps REF and LBI comparator active - enables low-power wake-up detection. |
| 2 FB | Feedback input | Connects to voltage divider between OUT and GND; sets output per VOUT = 1.25V × (R1 + R2)/R2 - enables precise adjustable regulation. |
| 3 REF | Precision reference output | 1.25V ±1.5%, 250µA source/20µA sink - usable as ADC reference or external bias; bypass with 0.22µF if loaded. |
| 4 LBO | Low-battery open-drain output | Sinks current when LBI < 1.25V - requires external pull-up to VOUT (≤VOUT); drives microcontroller interrupt or LED indicator. |
| 5 LBI | Low-battery input | Monitors input voltage via resistor divider; threshold = 1.25V - remains functional in shutdown mode for battery monitoring. |
| 6 OUT | Regulated output connection | Delivers final regulated voltage; also supplies bootstrapped power to internal circuitry - must connect to output capacitor with minimal trace length. |
| 7 GND | Power ground | Primary return path for switch current and feedback; requires direct solder to ground plane - critical for EMI control and efficiency. |
| 8 LX | Switch node | Drain of internal 1A N-MOSFET; connects to inductor and Schottky diode - high di/dt node; keep layout short and wide. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low start-up voltage | 0.7V minimum - enables operation from deeply discharged single-cell batteries in portable medical instruments. |
| Integrated low-battery detector | LBI/LBO pair with 1.25V threshold and hysteresis - eliminates need for external supervisor IC in glucose meters and PDAs. |
| Constant-off-time PFM control | No external oscillator required; self-regulating frequency adapts to load - simplifies design and improves light-load efficiency vs. PWM. |
| Active reference in shutdown | REF remains powered and stable during SHDN assertion - supports continuous battery monitoring without waking SMPS. |
| Bootstrapped internal supply | Derives gate drive from OUT pin - sustains regulation even as VIN drops below 1V post-startup, extending usable battery life. |
Applications
| Glucose Meters | Portable Data-Collection Terminals |
|---|---|
Use Scenario: Battery-powered handheld device measuring blood glucose concentration with LCD display and microcontroller. IC Role / Device Role / Timing Role: Step-up converter generating stable 3.3V or 5V rail from 1.5V–3.0V alkaline/NiMH battery stack. Use Value: 0.7V start-up ensures full battery utilization; 60µA quiescent current preserves shelf life; LBI/LBO enables low-battery alert before measurement failure. |
Use Scenario: Ruggedized barcode scanner or RFID reader operating on 2-cell AA batteries in field logistics. IC Role / Device Role / Timing Role: Adjustable-output DC-DC regulator powering MCU, sensor interface, and wireless transceiver from variable battery voltage. Use Value: FB-based adjustment accommodates varying system rail requirements; 500kHz switching enables compact 22µH inductor; >87% efficiency sustains runtime during burst transmissions. |
| Personal Digital Assistants | Medical Instrumentation |
Use Scenario: Palm-sized organizer with touch screen, flash memory, and serial interface, powered by two AAA cells. IC Role / Device Role / Timing Role: Primary voltage booster supplying 3.3V logic rail and 5V peripheral bus from decaying 1.8V–3.0V input. Use Value: Bootstrapped architecture maintains regulation as battery discharges below 1V; REF pin provides stable ADC reference for touchscreen calibration. |
Use Scenario: Portable ECG or pulse oximeter requiring clean, low-noise analog rails and long battery life. IC Role / Device Role / Timing Role: High-efficiency step-up regulator delivering isolated 5V for op-amp bias and 3.3V for digital controller. Use Value: 87% efficiency minimizes heat near sensitive analog circuitry; low ESR capacitor support reduces output ripple; LBO triggers audible low-battery warning. |
Availability
MAX757CSA+ is available at Aetrix Electronics and suitable for glucose meters, portable data-collection terminals, personal digital assistants, medical instrumentation, and 2-/3-cell battery-operated equipment requiring stable component supply and long-term lifecycle support.
Supply support for MAX757CSA+ 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 is a U.S.-based semiconductor company specializing in analog and mixed-signal ICs for power management, sensing, and communication applications.
The MAX757CSA+ belongs to Maxim's legacy step-up DC-DC converter product line, designed specifically for ultra-low-voltage battery-powered systems where start-up reliability, efficiency, and integrated supervision are critical.
FAQ
What is the minimum input voltage required for MAX757CSA+ to start up?
The MAX757CSA+ starts up from as low as 0.7V input voltage, verified across temperature and load conditions. This enables reliable operation from nearly depleted single-cell alkaline or NiMH batteries. Once started, it continues regulating even if input sags below 1V due to its bootstrapped internal supply derived from the OUT pin - a key advantage over conventional boost converters.
How is the output voltage set on the MAX757CSA+?
The MAX757CSA+ uses the FB (feedback) pin to set output voltage via an external resistor divider between OUT and GND. The formula is VOUT = 1.25V × (R1 + R2)/R2, where R2 connects to GND and R1 to OUT. The internal 1.25V reference (REF pin) is highly stable (±1.5% over temperature), ensuring accurate regulation - unlike the MAX756, which has fixed 3.3V/5V outputs selected by the 3/5 pin.
Does the MAX757CSA+ include low-battery detection capability?
Yes, the MAX757CSA+ integrates a dedicated low-battery detector with LBI (input) and LBO (open-drain output) pins. When the voltage at LBI falls below the internal 1.25V reference, LBO sinks current - usable to trigger MCU interrupts or LEDs. Critically, this function remains active even when SHDN is asserted, allowing continuous battery monitoring without powering the SMPS stage.
What is the switching frequency behavior of the MAX757CSA+?
The MAX757CSA+ uses a constant-off-time pulse-frequency modulation (PFM) scheme with no fixed oscillator. Switching frequency varies with load and input voltage - ranging from light-load minimum off-time (1µs) up to 500kHz maximum. This architecture delivers high efficiency at both heavy and light loads, avoids constant-frequency EMI peaks, and eliminates need for external timing components.
Can the MAX757CSA+ operate with a 22µH inductor?
Yes, the MAX757CSA+ is optimized for use with a 22µH surface-mount inductor, as shown in the Typical Operating Circuit. The internal 1A peak-current limit and 500kHz max frequency allow this value to deliver full rated output (e.g., 200mA at 5V from 2.5V input) with acceptable ripple and efficiency. For higher input voltages, a lower inductance (e.g., 10µH) may reduce ripple energy transfer.
MAX757CSA+ 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
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 0.7V
- Voltage - Input (Max):
- 7V
- Voltage - Output (Min/Fixed):
- 2.7V
- Voltage - Output (Max):
- 5.5V
- Current - Output:
- -
- Frequency - Switching:
- 500kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX757CSA+ FAQ
1.How can I place an order for MAX757CSA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX757CSA+ 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 MAX757CSA+ reliable?
The price and inventory of MAX757CSA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX757CSA+ is usually 5 days.
3.What payment methods are accepted for MAX757CSA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX757CSA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX757CSA+?
MAX757CSA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX757CSA+ 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 MAX757CSA+?
For technical support, including MAX757CSA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX757CSA+ requirements.
6.How does Aetrix verify that MAX757CSA+ is sourced from the original manufacturer or authorized distributors?
All MAX757CSA+ 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 MAX757CSA+ meets industry standards.
7.What is the process for return or replacement of MAX757CSA+?
All MAX757CSA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX757CSA+, 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 MAX757CSA+ part is unused and in its original packaging.
Return procedure for MAX757CSA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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