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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 300MA 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,545
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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 accepts input voltages as low as 0.7V, delivers adjustable output from 2.7V to 5.5V (set via external feedback resistors), achieves >87% efficiency at 200mA load, operates up to 500kHz switching frequency, and draws only 60µA quiescent current. It is used in glucose meters and portable data-collection equipment requiring compact, high-efficiency boost conversion.
For engineers reviewing the MAX757CSA datasheet, MAX757CSA pinout, MAX757CSA application, or MAX757CSA equivalent, this page provides verified technical context, validated pin functions, confirmed operating parameters, real-world application roles, and two rigorously cross-checked alternative parts - all specific to the MAX757CSA SO-8 variant.
Technical Context
The MAX757CSA implements a constant-off-time pulse-frequency modulation (PFM) control scheme with no oscillator, enabling ultra-low quiescent current (20µA in shutdown) while maintaining high efficiency across wide load ranges. Its internal 1A/0.5Ω N-channel MOSFET power switch supports start-up from 0.7V and sustains operation down to <1V after startup.
It integrates a precision 1.25V reference (±1.5% over temperature), active low-battery detection (LBI/LBO with 1.25V threshold), and feedback-controlled output regulation. The FB pin accepts external resistor dividers to set output voltage per VOUT = 1.25V × (1 + R1/R2), with FB input bias current ≤100nA ensuring accuracy with high-value resistors.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 0.7V minimum start-up; operates down to <1V after startup - enables single-cell alkaline or NiMH battery use. |
| Output Voltage Range | 2.7V to 5.5V, adjustable via external FB resistor divider - supports custom rail generation without fixed-output constraints. |
| Switching Frequency | Up to 500kHz - permits use of small surface-mount inductors (<5mm diameter) and reduces solution footprint. |
| Efficiency | >87% at 200mA load - minimizes thermal stress and extends battery life in portable medical and handheld devices. |
| Quiescent Current | 60µA typical operating; 20µA in shutdown - preserves battery charge during standby in intermittently powered systems. |
| Reference Voltage | 1.25V ±1.5% over temperature - provides stable, accurate feedback for precise output regulation and external analog circuit biasing. |
| Low-Battery Detection | 1.25V LBI threshold with 25mV hysteresis - enables reliable battery monitoring without external comparators. |
Pinout & Package
MAX757CSA is housed in an 8-pin SO (Small Outline) package, 3.9mm × 4.9mm body size, 1.27mm pitch, JEDEC MS-012AC compliant. Pin 1 marked with dot; pin numbering counterclockwise from top-left corner when viewed top-side.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 SHDN | Shutdown control input | Active-low logic input; disables SMPS but keeps reference and LBI comparator active - enables system-level power sequencing. |
| 2 FB | Feedback input | Connects to voltage divider between OUT and GND; sets output voltage via VOUT = 1.25V × (1 + R1/R2) - enables precise, user-defined output regulation. |
| 3 REF | 1.25V reference output | Stable, buffered reference with 250µA source/20µA sink capability; remains active in shutdown - supports external ADC biasing or comparator references. |
| 4 LBO | Low-battery open-drain output | Sinks current when LBI falls below 1.25V; requires external pull-up to VOUT - provides fail-safe battery status signal to microcontroller GPIO. |
| 5 LBI | Low-battery input | Monitors input voltage via external resistor divider; threshold = 1.25V - eliminates need for discrete voltage monitor ICs. |
| 6 OUT | Regulated output connection | Delivers boosted output; also supplies bootstrapped power to internal circuitry - must connect directly to output capacitor with minimal trace length. |
| 7 GND | Power ground | Low-impedance return path; soldered directly to PCB ground plane - critical for noise suppression and thermal performance. |
| 8 LX | Switch node | Drain of internal 1A/0.5Ω N-MOSFET; connects to inductor and Schottky diode anode - high di/dt node requiring short, wide traces. |
Key Features
| Feature | Design Value |
|---|---|
| 0.7V minimum start-up voltage | Enables operation from deeply discharged single-cell batteries (e.g., 1.0V alkaline), extending usable battery life in glucose meters. |
| Adjustable output (2.7V–5.5V) | Eliminates need for multiple fixed-output variants; one BOM item covers diverse system rail requirements via resistor selection. |
| 60µA quiescent current | Reduces standby power loss by >5× vs. bipolar regulators, critical for multi-year battery life in portable medical instrumentation. |
| Integrated low-battery detector | Combines LBI comparator and open-drain LBO output on-chip - saves board space and simplifies firmware battery-state polling. |
| 1.25V ±1.5% reference | Provides stable, temperature-compensated reference for both internal regulation and external analog circuits - improves overall system accuracy. |
Applications
| Glucose Meters | Portable Data-Collection Equipment |
|---|---|
|
Use Scenario: Battery-powered handheld device measuring blood glucose concentration using electrochemical test strips. IC Role / Device Role / Timing Role: Step-up regulator generating stable 3.3V or 5V rail from aging 1.5V alkaline cell to power microcontroller, LCD, and analog front-end. Use Value: 0.7V start-up ensures full functionality even as battery depletes to 0.9V; 87% efficiency extends single-battery life beyond 500 tests. |
Use Scenario: Ruggedized handheld scanner collecting barcodes or RFID tags in field logistics or warehouse environments. IC Role / Device Role / Timing Role: Boost converter supplying regulated 3.3V to MCU, radio transceiver, and sensor interface from dual AA cells. Use Value: 20µA shutdown current preserves battery during idle periods; integrated LBI/LBO enables automatic low-power mode entry before brownout. |
| Personal Data Communicators | Medical Instrumentation |
|
Use Scenario: Palm-sized PDA with touch interface, flash memory, and serial connectivity for clinical note-taking. IC Role / Device Role / Timing Role: Adjustable-output DC-DC converter delivering 3.3V to processor and 5V to USB interface from 2-cell NiMH pack. Use Value: FB pin allows dynamic rail selection; 500kHz switching enables compact 22µH inductor and low-profile 100µF tantalum output cap. |
Use Scenario: Portable ECG or pulse oximeter requiring low-noise analog supply and long battery runtime. IC Role / Device Role / Timing Role: Primary power regulator generating clean 3.3V for analog signal chain and digital logic from primary lithium coin cell. Use Value: 1.25V reference with ±1.5% tolerance supports accurate ADC reference; REF pin remains active in shutdown for wake-on-event designs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable-output boost converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS61040DRVR | Fixed 5V output only; no adjustable FB pin; 28V absolute max switch voltage vs. MAX757CSA's 7V; 500kHz fixed PWM vs. PFM. | Lacks output adjustability and low-battery detection; suited for fixed-rail systems where simplicity outweighs flexibility. | Select TPS61040DRVR only if 5V output suffices and LBI/LBO functionality is handled externally. |
| LT1930ES5#TRMPBF | Adjustable output (1.25V–34V); higher 36V switch rating; 1.2MHz switching; no integrated LBI/LBO; 100µA quiescent current. | Supports wider VIN/VOUT ratios but consumes >1.5× more quiescent current; requires external battery monitor. | Choose LT1930ES5#TRMPBF for high-VIN industrial boost needs, not for ultra-low-power medical or handheld use. |
Compared with TPS61040DRVR and LT1930ES5#TRMPBF, the MAX757CSA uniquely combines adjustable output, sub-1V start-up, integrated low-battery detection, and 20µA shutdown current - making it optimal for space-constrained, battery-sensitive medical and portable electronics where feature integration reduces BOM count and design risk.
Availability
MAX757CSA is available at Aetrix Electronics and suitable for glucose meters, portable data-collection equipment, personal data communicators, and medical instrumentation requiring stable component supply, long-lifecycle support, and consistent parametric performance across production batches.
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 (now part of Analog Devices) is a U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, medical, and communications applications.
The MAX757CSA belongs to Maxim's legacy high-efficiency, low-voltage DC-DC converter product line, engineered specifically for battery-powered portable electronics demanding ultra-low quiescent current, wide input range, and integrated power-monitoring features.
FAQ
What is the minimum input voltage required for the MAX757CSA to start up?
The MAX757CSA requires a minimum input voltage of 0.7V to initiate start-up under typical conditions. Once running, it sustains operation with input as low as <1V due to internal bootstrapping from the OUT pin. This behavior is confirmed in the Typical Operating Characteristics graph "Minimum Start-Up Input Voltage vs. Load Current" and Electrical Characteristics table, where 0.7V is specified as the minimum start-up supply voltage at 20mA load.
How is the output voltage set on the MAX757CSA?
The MAX757CSA output voltage is set externally using a resistor divider connected between OUT and GND, with the midpoint feeding the FB pin. The relationship is VOUT = 1.25V × (1 + R1/R2), where R1 connects to OUT and R2 to GND. This configuration is explicitly defined in the "Design Procedure" section and verified in Figure 1 and the Pin Description table for the MAX757 variant.
Does the MAX757CSA include low-battery detection, and how is it implemented?
Yes, the MAX757CSA includes an integrated low-battery detector with LBI (input) and LBO (open-drain output) pins. When the voltage at LBI drops below the internal 1.25V reference, LBO sinks current to GND. The threshold is set by an external resistor divider from VIN to LBI, per R3 = [(VIN / 1.25V) − 1] × R4. This function remains active even in shutdown mode, as stated in the Pin Description and Detailed Description sections.
What package type and dimensions does the MAX757CSA use?
The MAX757CSA uses an 8-pin SO (Small Outline) package conforming to JEDEC MS-012AC. Its body dimensions are 3.9mm × 4.9mm, with 1.27mm lead pitch and 1.75mm maximum height. These mechanical specifications are documented in the "Package Information" section, including millimeter and inch tolerances for A, B, C, D, E, and e dimensions.
What is the switching frequency behavior of the MAX757CSA under varying loads?
The MAX757CSA employs a variable-frequency pulse-frequency modulation (PFM) scheme with no fixed oscillator. Switching frequency increases with load - reaching up to 500kHz at full load - and decreases at light loads due to its constant-off-time control architecture. This behavior is illustrated in the "Switching Frequency vs. Load Current" plot (MAX756-4) and described in the "Pulse-Frequency Modulation Control Scheme" subsection.
MAX757CSA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- 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):
- 5.5V
- Voltage - Output (Min/Fixed):
- 2.7V
- Voltage - Output (Max):
- 5.5V
- Current - Output:
- 300mA
- 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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