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Analog Devices Inc./Maxim Integrated MAX8940EXK28+
- Part No.:
- MAX8940EXK28+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 5-TSSOP, SC-70-5, SOT-353
- Datasheet:
-
MAX8940EXK28+.pdf
- Description:
- IC REG LIN LOW NOISE HIGH PSRR
- Quantity:
- Payment:
- Shipping:
Inventory:831
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Product details
Overview
The MAX8940EXK28+ from Maxim Integrated is a low-noise, low-dropout linear regulator preset to 2.8V output, delivering up to 120mA continuous current with 135mV dropout at full load, 25µVRMS output noise (100Hz–100kHz), and 45dB PSRR at 100kHz. It employs a p-channel MOSFET pass transistor, achieves 40µA ground current under light load, and operates from 2.8V to 6V input - ideal for battery-powered portable electronics requiring stable, quiet voltage regulation.
For engineers reviewing the MAX8940EXK28+ datasheet, MAX8940EXK28+ pinout, MAX8940EXK28+ application, or MAX8940EXK28+ equivalent, key selection criteria include its SC70-5 package footprint, guaranteed 120mA output with thermal/overcurrent protection, low-noise performance enabled by BP-pin bypassing, and compatibility with 1µF ceramic output capacitors across temperature.
Technical Context
The MAX8940EXK28+ uses an internal 1.225V bandgap reference and error amplifier to regulate output via feedback from an integrated resistor divider. Its p-channel MOSFET pass transistor (typ. RDS(ON) = 1Ω) eliminates base-drive current, enabling ultra-low quiescent current and consistent dropout behavior across temperature.
Shutdown is controlled by a logic-compatible SHDN pin (0.4V low, 1.5V high), disabling reference, error amp, and gate drive to reduce supply current below 1µA. A dedicated BP pin accepts a 10nF capacitor to shunt high-frequency noise from the bandgap core, directly reducing RMS output noise to 25µV without external filtering.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 2.8V ±3% over -40°C to +85°C - ensures stable bias for RF front-ends and analog sensors. |
| Max Output Current | 120mA continuous - sufficient for powering single-core microcontrollers or low-power DSPs in portable devices. |
| Dropout Voltage | 135mV at 120mA load - enables operation down to 2.93V input when regulating 2.8V, extending battery runtime in Li-ion and coin-cell systems. |
| Output Noise | 25µVRMS (100Hz–100kHz) with 10nF BP capacitor - meets stringent noise requirements for ADC references and audio codecs. |
| PSRR | 45dB at 100kHz - suppresses switching noise from DC-DC converters sharing the same input rail. |
| Ground Current | 40µA at no load - minimizes standby power loss in always-on subsystems like Bluetooth LE receivers. |
| Shutdown Current | <1µA - enables deep-sleep modes in wearable and IoT edge nodes without compromising wake-up latency. |
Pinout & Package
Package: 5-pin SC70 (X5-1), 1.25mm × 0.8mm footprint, 0.65mm pitch, RoHS-compliant lead-free finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - IN | Unregulated input supply | Accepts 2.8V–6V input; must be bypassed with ≥1µF ceramic capacitor close to pin for stability and transient response. |
| 2 - GND | Power and thermal ground | Serves as primary return path and heat sink; requires direct connection to large copper pour for thermal management. |
| 3 - SHDN | Active-low enable control | Pulled low (<0.4V) disables regulator output and reduces supply current to <1µA; tied to IN for always-on operation. |
| 4 - BP | Noise bypass terminal | Connects to OUT via 10nF capacitor to shunt bandgap noise; internally shorted to OUT during shutdown. |
| 5 - OUT | Regulated 2.8V output | Delivers up to 120mA; requires ≥1µF ceramic capacitor to GND; output impedance optimized for fast load transient recovery. |
Key Features
| Feature | Design Value |
|---|---|
| Low-noise architecture with BP pin | 25µVRMS output noise achieved via dedicated noise-bypass path - eliminates need for post-regulation LC filters in sensitive analog chains. |
| p-Channel MOSFET pass element | 1Ω typical RDS(ON) enables 135mV dropout at 120mA and eliminates base-drive current - improves efficiency over PNP-based LDOs in battery discharge profiles. |
| Stable with 1µF ceramic output cap | Guaranteed stability across -40°C to +85°C using X7R/X5R dielectrics - reduces BOM count and PCB area vs. larger tantalum or polymer alternatives. |
| Integrated protection | Thermal shutdown (160°C activation, 10°C hysteresis) and current limiting (130–300mA range) prevent damage during fault conditions without external circuitry. |
| Ultra-low quiescent current | 40µA ground current at no load and 220µA in dropout - extends shelf life and operational time in energy-harvesting and coin-cell applications. |
Applications
| Wireless Audio Accessories | Digital Camera Sensor Bias |
|---|---|
Use Scenario: Powering MEMS microphones and Class-D headphone amplifiers in Bluetooth earbuds. IC Role / Device Role / Timing Role: Low-noise 2.8V supply for analog signal chain and RF interface ICs. Use Value: 25µVRMS noise prevents audible hiss; 45dB PSRR rejects noise from 2.4GHz RF transceivers sharing the same battery rail. | Use Scenario: Providing clean bias voltage to CMOS image sensor analog front-end and ADC reference. IC Role / Device Role / Timing Role: Precision low-noise LDO for image sensor pixel array and column readout circuits. Use Value: Fixed 2.8V output matches common sensor VDDIO requirements; 135mV dropout allows operation until Li-ion cell drops to 2.93V. |
| Portable Medical Sensors | Industrial Handheld Terminals |
Use Scenario: Supplying ECG/PPG analog front-end and low-power MCU in disposable wearable patches. IC Role / Device Role / Timing Role: Primary regulated rail for analog sensing and digital processing subsystems. Use Value: 40µA ground current extends battery life beyond 7 days on CR2032; thermal protection prevents overheating during extended clinical monitoring. | Use Scenario: Regulating power for barcode scanner modules, touch controllers, and secure element ICs in rugged handheld scanners. IC Role / Device Role / Timing Role: Point-of-load regulator for mixed-signal peripherals requiring stable voltage under variable load transients. Use Value: Excellent load transient response (≤10mV deviation) maintains communication integrity during rapid laser activation and data transmission bursts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar low-noise LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS7A2028PDQNR | 2.8V fixed, 300mA output, 140mV dropout at 300mA, 12µVRMS noise, 65dB PSRR at 100kHz, SOT-23-5 package | Higher output current and lower noise, but larger SOT-23 footprint and higher minimum input voltage (1.6V) not applicable here | Select when >120mA load or sub-25µV noise is required; verify PCB layout change for SOT-23 pad geometry. |
| MCP1700T-2802E/TT | 2.8V fixed, 250mA output, 178mV dropout at 250mA, 30µVRMS noise, 60dB PSRR at 100kHz, SOT-23-3 package (no BP pin) | No BP pin for noise reduction; lower PSRR and higher noise; only 3 pins limits flexibility in noise-critical designs | Choose for cost-sensitive, non-noise-critical applications where BP bypassing is unnecessary and 3-pin simplicity is preferred. |
Compared with TPS7A2028PDQNR and MCP1700T-2802E/TT, the MAX8940EXK28+ uniquely combines SC70-5 footprint, BP-enabled 25µVRMS noise, and 40µA quiescent current - making it optimal for space-constrained, battery-powered systems demanding both ultra-low noise and minimal standby power.
Availability
MAX8940EXK28+ is available at Aetrix Electronics and suitable for wireless audio accessories, digital camera sensor bias, portable medical sensors, and industrial handheld terminals requiring stable component supply with guaranteed long-term availability.
Supply support for MAX8940EXK28+ 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, communications, and consumer applications.
The MAX8940 belongs to Maxim's precision low-noise LDO family, engineered specifically for portable and battery-operated equipment where minimal dropout, ultra-low noise, and micropower operation are critical design constraints.
FAQ
What is the maximum input voltage rating for the MAX8940EXK28+?
The MAX8940EXK28+ has an absolute maximum input voltage of +7V referenced to GND. However, its specified operating input voltage range is 2.8V to 6V. Exceeding 6V may cause functional instability or accelerated aging, even if within absolute maximum limits. Always operate the MAX8940EXK28+ within 2.8V–6V for reliable performance per its datasheet specifications.
Does the MAX8940EXK28+ require an external capacitor on the BP pin?
Yes, the MAX8940EXK28+ requires a 10nF capacitor connected between the BP and OUT pins to achieve its specified 25µVRMS output noise. Omitting this capacitor increases output noise significantly - to approximately 13µVRMS at 80mA load - and degrades high-frequency PSRR. The BP capacitor must be placed as close as possible to the BP and OUT pins to minimize parasitic inductance.
Is the MAX8940EXK28+ compatible with 1µF X7R ceramic output capacitors across temperature?
Yes, the MAX8940EXK28+ is fully stable with 1µF X7R or X5R ceramic output capacitors over its full operating temperature range (-40°C to +85°C). Unlike Z5U or Y5V dielectrics, X7R maintains sufficient capacitance and low ESR across temperature, satisfying the regulator's stability criteria without requiring larger values or additional compensation components.
What happens to the output of the MAX8940EXK28+ during shutdown?
When the SHDN pin is pulled low, the MAX8940EXK28+ disables its internal voltage reference, error amplifier, and gate-drive circuitry, placing the OUT pin in a high-impedance state. The output voltage decays passively through the load and output capacitor; there is no active discharge path. Shutdown exit delay is typically 300µs, measured from SHDN rising to 90% of final VOUT.
How does thermal protection operate in the MAX8940EXK28+?
The MAX8940EXK28+ activates thermal shutdown at a junction temperature of +160°C, turning off the pass transistor to halt power dissipation. After cooling by 10°C (to +150°C), the device automatically resumes regulation. This hysteresis prevents oscillation near the trip point. Continuous operation above +150°C junction temperature is not recommended, as it exceeds the absolute maximum rating and risks long-term reliability degradation.
MAX8940EXK28+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 5-TSSOP, SC-70-5, SOT-353
- Packaging:
- Bulk
- Product Status:
- Active
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 6V
- Voltage - Output (Min/Fixed):
- 2.8V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 0.135V @ 120mA (Typ)
- Current - Output:
- 120mA
- Current - Quiescent (Iq):
- 90 µA
- Current - Supply (Max):
- -
- PSRR:
- 65dB ~ 45dB (10kHz ~ 100kHz)
- Control Features:
- Enable
- Protection Features:
- Over Current, Over Temperature
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SC-70-5
MAX8940EXK28+ FAQ
1.How can I place an order for MAX8940EXK28+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX8940EXK28+ 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 MAX8940EXK28+ reliable?
The price and inventory of MAX8940EXK28+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX8940EXK28+ is usually 5 days.
3.What payment methods are accepted for MAX8940EXK28+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX8940EXK28+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX8940EXK28+?
MAX8940EXK28+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX8940EXK28+ 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 MAX8940EXK28+?
For technical support, including MAX8940EXK28+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX8940EXK28+ requirements.
6.How does Aetrix verify that MAX8940EXK28+ is sourced from the original manufacturer or authorized distributors?
All MAX8940EXK28+ 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 MAX8940EXK28+ meets industry standards.
7.What is the process for return or replacement of MAX8940EXK28+?
All MAX8940EXK28+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX8940EXK28+, 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 MAX8940EXK28+ part is unused and in its original packaging.
Return procedure for MAX8940EXK28+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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