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Analog Devices Inc./Maxim Integrated MAX640CSA-TG074
- Part No.:
- MAX640CSA-TG074
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX640CSA-TG074.pdf
- Description:
- IC REG BUCK ADJ/1.3V 225MA 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,000
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Product details
Overview
MAX640CSA-TG074 from Maxim Integrated is a 3.3V fixed-output, high-efficiency step-down DC-DC converter with PFM control, 10µA quiescent current, 225mA output capability, and integrated 1A PMOS switch. It operates from 4V to 11.5V input and is used in portable instruments, battery-powered 9V-to-3.3V conversion, and low-power embedded systems requiring minimal external components.
For engineers reviewing the MAX640CSA-TG074 datasheet, MAX640CSA-TG074 pinout, MAX640CSA-TG074 application, or MAX640CSA-TG074 equivalent, key selection criteria include its preset 3.3V output, low-IQ operation across light-to-moderate loads, internal low-battery detection comparator (LBI/LBO), SO-8 package compatibility, and absence of external feedback resistors in fixed-voltage mode.
Technical Context
The MAX640CSA-TG074 employs a current-limiting pulse-frequency-modulated (PFM) control scheme that dynamically adjusts switching frequency and duty cycle to maintain constant peak inductor current (IPEAK = 50µs × VIN/L), enabling high efficiency from 10µA to 225mA load range. Its internal 1A PMOS switch eliminates external FET requirements.
It integrates a dual-mode feedback pin (VFB): grounded for fixed 3.3V output or connected to an external divider for adjustable regulation. The low-battery detector compares LBI voltage against a 1.28V internal reference and asserts open-drain LBO when threshold is crossed - functional even in shutdown mode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±3% (guaranteed over temperature and load) |
| Input Voltage Range | 4.0V to 11.5V - supports single 9V battery or multi-cell Li-ion inputs |
| Max Output Current | 225mA - sufficient for microcontrollers, sensors, and RF modules |
| Quiescent Current | 10µA - enables >1-year battery life in always-on sensor nodes |
| Efficiency | Up to 94% at 100mA (VIN = 6V, L = 100µH) - exceeds linear regulators under medium load |
| Switch On-Resistance | 0.8Ω typical - minimizes dropout and conduction loss at full load |
| Low-Battery Threshold | 1.28V on LBI pin - configurable via external resistor divider for system-level brownout detection |
Pinout & Package
MAX640CSA-TG074 is housed in an 8-pin SOIC (SO) package with standard .150" width, JEDEC MS-012 outline, and RoHS-compliant lead finish. Pin 1 is marked by a beveled corner or dot.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VOUT | Regulated output sense node | Internally connected to feedback divider; must connect directly to output capacitor for stable regulation |
| LBO | Open-drain low-battery output | Sinks up to 10mA when LBI < 1.28V; requires external pull-up for logic-level signaling |
| LBI | Low-battery input comparator | Monitors system supply via resistor divider; remains active during SHDN |
| GND | Power and signal ground reference | Must tie to input/output capacitor grounds at single point to minimize ground bounce |
| LX | PMOS switch drain terminal | Drives external inductor; peak current limited to 600mA; requires Schottky catch diode |
| V+ | Positive input supply | Accepts 4–11.5V; must be decoupled with ≥33µF low-ESR capacitor near pin |
| VFB | Dual-mode feedback input | Grounded for fixed 3.3V; externally biased for adjustable output (1.3V–VIN) |
| SHDN | Active-low shutdown control | Pulled below 0.8V disables LX; pulled above 2V enables regulation; tied to V+ if unused |
Key Features
| Feature | Design Value |
|---|---|
| PFM control architecture | Maintains >85% efficiency down to 10µA load without forced PWM, eliminating light-load inefficiency cliffs |
| Integrated 1A PMOS switch | Reduces BOM count to only inductor, diode, and two capacitors - no external MOSFET or driver required |
| Low-battery detection circuit | On-chip 1.28V reference and comparator enable reliable system-level power monitoring without extra ICs |
| Shutdown current | ≤1µA total device current in SHDN - preserves battery charge during extended sleep modes |
| Fixed 3.3V output option | No external feedback resistors needed - simplifies layout and eliminates resistor tolerance errors |
Applications
| Portable Instrument Power | 9V Battery to 3.3V Conversion |
|---|---|
Use Scenario: Handheld multimeter powered by a single 9V alkaline battery with MCU, LCD, and analog front-end. IC Role / Device Role / Timing Role: Primary 3.3V supply regulator delivering up to 200mA with ultra-low quiescent current during measurement standby. Use Value: Extends battery life beyond 500 hours while maintaining tight 3.3V regulation across battery discharge curve (9V → 4.5V). |
Use Scenario: Industrial handheld terminal using 9V battery to power 3.3V ARM Cortex-M0+ microcontroller and UART interface. IC Role / Device Role / Timing Role: Step-down converter replacing inefficient linear regulator; provides clean 3.3V rail with fast transient response to CPU burst loads. Use Value: Achieves 91% efficiency at 150mA, reducing thermal load and enabling compact enclosure design without heatsinking. |
| Low-Power Sensor Node | High-Efficiency Linear Regulator Replacement |
Use Scenario: Wireless environmental sensor node (temperature/humidity) operating on AA batteries with BLE radio and sleep current <10µA. IC Role / Device Role / Timing Role: Always-on 3.3V supply enabling sub-µA deep-sleep current while supporting 225mA radio transmit peaks. Use Value: 10µA quiescent current ensures >2-year battery life; PFM modulation avoids switching noise interference with sensitive analog measurements. |
Use Scenario: Legacy 5V system redesign requiring 3.3V for new FPGA I/O bank, previously served by LM1117-3.3. IC Role / Device Role / Timing Role: Drop-in efficiency upgrade replacing linear regulator; same input/output capacitor footprint with added inductor/diode. Use Value: Reduces power dissipation from 350mW (at 150mA) to <50mW - eliminates thermal derating and enables higher ambient operating temperature. |
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 |
|---|---|---|---|
| TPS62231DRYR | 3.3V fixed, 300mA output, 17µA IQ, PWM-only control (no PFM), 2.05–6.5V input | Higher max current but narrower input range; lacks low-battery comparator and shutdown leakage <1µA | Prefer when higher output current or tighter output accuracy (±1%) is required; not suitable for 9V battery or low-battery monitoring use cases |
| RT8059ZSP | 3.3V fixed, 300mA, 25µA IQ, PFM/PWM hybrid, 2.5–5.5V input, no LBI/LBO pins | Lower input voltage ceiling; no integrated battery monitor; requires external feedback for adjustability | Choose for cost-sensitive consumer applications with 3.3V/3.6V Li-ion input; avoid where 4–11.5V range or system-level brownout signaling is mandatory |
Compared with TPS62231DRYR and RT8059ZSP, the MAX640CSA-TG074 uniquely combines wide 4–11.5V input support, true 10µA quiescent current, built-in low-battery detection, and fixed 3.3V operation without external resistors - making it optimal for legacy 9V-powered industrial and portable equipment upgrades.
Availability
MAX640CSA-TG074 is available at Aetrix Electronics and suitable for portable instrumentation, battery-powered wireless sensors, and industrial handheld terminals requiring stable component supply with long-term lifecycle assurance.
Supply support for MAX640CSA-TG074 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, communications, and consumer applications.
The MAX640CSA-TG074 belongs to Maxim's legacy high-efficiency, low-IQ DC-DC converter family targeting battery-operated systems where runtime, simplicity, and reliability outweigh ultra-high switching frequency or digital programmability.
FAQ
What is the guaranteed output voltage tolerance for MAX640CSA-TG074?
The MAX640CSA-TG074 guarantees a 3.3V output within ±3% (3.17V to 3.43V) over full temperature range (-40°C to +85°C), input voltage (4V to 11.5V), and load current (0 to 225mA), as specified in the Electrical Characteristics table of the official datasheet. This tolerance is achieved using an internal trimmed voltage divider referenced to a 1.28V bandgap.
Can MAX640CSA-TG074 operate from a single 3.7V Li-ion cell?
No - the MAX640CSA-TG074 has a minimum input voltage of 4.0V per Absolute Maximum Ratings and Electrical Characteristics tables. A 3.7V Li-ion cell falls below this threshold across most of its discharge curve and will not sustain regulation. For 3.6V nominal inputs, consider the MAX653 (3.0V output, 3.5V min input) or newer alternatives like the MAX17222.
Does MAX640CSA-TG074 require an external Schottky diode?
Yes - the MAX640CSA-TG074 requires an external Schottky diode (e.g., 1N5817 or equivalent) connected between LX and VOUT. The IC contains only the PMOS switch; the diode provides the freewheeling path during switch-off. Using a slow rectifier like 1N4001 causes excessive losses and potential instability due to reverse recovery.
How does the low-battery detector function in shutdown mode?
The low-battery detector in the MAX640CSA-TG074 remains fully operational during shutdown: LBI continues monitoring the input voltage divider, and LBO asserts low when LBI drops below 1.28V - independent of SHDN state. This allows host systems to detect battery depletion even when the main 3.3V rail is disabled.
What is the recommended inductor value for MAX640CSA-TG074 at 100mA load?
For 100mA continuous output, Maxim recommends a 100µH inductor with ≥600mA saturation current (e.g., Sumida CDR74-100 or equivalent). This value balances efficiency (>90%), size, and transient response per Typical Operating Characteristics graphs. Inductors below 100µH risk peak current exceedance and reduced efficiency.
MAX640CSA-TG074 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-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 (3.3V)
- Voltage - Output (Max):
- 11.5V
- Current - Output:
- 225mA
- Frequency - Switching:
- -
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX640CSA-TG074 FAQ
1.How can I place an order for MAX640CSA-TG074 through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX640CSA-TG074 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 MAX640CSA-TG074 reliable?
The price and inventory of MAX640CSA-TG074 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX640CSA-TG074 is usually 5 days.
3.What payment methods are accepted for MAX640CSA-TG074?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX640CSA-TG074 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX640CSA-TG074?
MAX640CSA-TG074 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX640CSA-TG074 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 MAX640CSA-TG074?
For technical support, including MAX640CSA-TG074 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX640CSA-TG074 requirements.
6.How does Aetrix verify that MAX640CSA-TG074 is sourced from the original manufacturer or authorized distributors?
All MAX640CSA-TG074 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 MAX640CSA-TG074 meets industry standards.
7.What is the process for return or replacement of MAX640CSA-TG074?
All MAX640CSA-TG074 units undergo pre-shipment inspection (PSI). If there is an issue with MAX640CSA-TG074, 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 MAX640CSA-TG074 part is unused and in its original packaging.
Return procedure for MAX640CSA-TG074:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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