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Analog Devices Inc./Maxim Integrated MAX1678EUA+
- Part No.:
- MAX1678EUA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
MAX1678EUA+.pdf
- Description:
- IC REG BST ADJ/2V 550MA 8UMAX
- Quantity:
- Payment:
- Shipping:
Inventory:1,224
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Product details
Overview
MAX1678EUA+ from Maxim Integrated is a synchronous-rectified, pulse-frequency-modulated (PFM) step-up DC-DC converter optimized for 1–3-cell alkaline/NiMH/NiCd or single-cell Li-ion battery systems. It guarantees 0.87V start-up, delivers up to 90% efficiency at 50mA load, and integrates a 1Ω N-channel MOSFET switch, synchronous rectifier, and power-fail comparator (PFI/PFO). It powers pagers, remote controls, and personal medical monitors requiring ultra-low quiescent current.
For engineers reviewing the MAX1678EUA+ datasheet, MAX1678EUA+ pinout, MAX1678EUA+ application, or MAX1678EUA+ equivalent, this page provides verified technical context, validated pin functions, confirmed dual-mode output configuration (fixed 3.3V or adjustable 2V–5.5V), and real-world EMI-suppression behavior via integrated damping switch - all critical for low-noise, battery-life-sensitive designs.
Technical Context
The MAX1678EUA+ employs a constant-peak-current PFM control scheme with input-voltage-dependent on-time (tON = K/VBATT, K = 8 V·µs typical) to maintain high efficiency across wide load ranges (10µA–50mA). Its internal architecture includes a bootstrapped OUT supply, zero-crossing detection for synchronous rectifier turn-off, and an integrated inductor-damping switch that connects LX to BATT during dead time to suppress LC ringing.
It features dual regulation modes: fixed 3.3V output when FB is grounded, or adjustable 2V–5.5V using external resistive feedback (FB regulated to 1.23V). The power-fail comparator (PFI threshold = 614mV ±2% hysteresis) drives open-drain PFO, enabling system-level brown-out detection without external components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Start-up Voltage | 0.87V guaranteed - enables operation from nearly-dead single-cell alkaline batteries. |
| Quiescent Current | 37µA into BATT at +25°C - extends shelf life and sleep-mode runtime in battery-powered devices. |
| Efficiency | Up to 90% at 20mA load (VIN = 1.5V → 3.3V) - minimizes thermal stress and maximizes usable battery energy. |
| Output Modes | Fixed 3.3V (FB = GND) or adjustable 2V–5.5V (FB = resistor divider) - supports diverse system voltage rails with no extra ICs. |
| Shutdown Current | 2µA logic-controlled shutdown (SHDN = GND) - reduces system standby power to near-zero. |
| Power-Fail Detection | PFI trip = 614mV ±2% hysteresis; PFO sinks current when triggered - provides reliable low-battery warning with minimal external parts. |
| Package | 8-pin µMAX (3mm × 3mm × 1.1mm) - enables ultra-compact PCB layouts in space-constrained portable electronics. |
Pinout & Package
MAX1678EUA+ is housed in an 8-pin µMAX package (3mm × 3mm, 1.1mm height), specified for operation from –40°C to +85°C. Pin spacing is 0.65mm; exposed pad is not electrically connected.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BATT (Pin 1) | Battery power input | Main supply path; reverse-battery protected up to 220mA by internal 5Ω series limiter. |
| PFI (Pin 2) | Power-fail input | Analog comparator input referenced to 614mV; 10nA max leakage enables high-impedance resistor-divider design. |
| PFO (Pin 3) | Open-drain power-fail output | Sinks current when PFI < 614mV; compatible with microcontroller interrupt or LED driver inputs. |
| SHDN (Pin 4) | Active-low shutdown control | Logic input; pulls low to enter 2µA shutdown mode; connect to BATT for always-on operation. |
| FB (Pin 5) | Feedback input | Regulates to 1.23V; grounding selects fixed 3.3V mode; resistor divider enables 2V–5.5V adjustment. |
| GND (Pin 6) | Ground reference | Common return for power, feedback, and comparator circuits; requires star-ground layout for stability. |
| LX (Pin 7) | Switch node | Drain connection of internal N-channel MOSFET and P-channel synchronous rectifier; high dv/dt node requiring tight layout. |
| OUT (Pin 8) | Power output & bootstrap supply | Delivers regulated output; also powers internal circuitry via bootstrapping once VOUT > 1.7V. |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectification | Integrated P-channel catch device eliminates external Schottky diode - reduces BOM count and forward-drop losses. |
| Inductor damping switch | Internal switch connects LX to BATT during dead time - suppresses EMI-generating LC ringing without affecting output ripple. |
| Dual-mode output | Single-pin (FB) selection between factory-trimmed 3.3V or user-adjustable 2V–5.5V - simplifies design reuse across product variants. |
| Ultra-low start-up voltage | 0.87V minimum - enables operation from weak primary cells where competing converters fail to initiate. |
| Low-noise PFM control | Variable-frequency operation avoids fixed switching harmonics - eases EMI filtering in RF-sensitive applications like pagers. |
Applications
| Pagers | Remote Controls |
|---|---|
Use Scenario: Compact handheld paging devices powered by two AA alkaline cells, requiring stable 3.3V rail for RF receiver and display driver. IC Role / Device Role / Timing Role: Primary step-up regulator supplying 3.3V from 1.8V–3.0V input; manages dynamic load transients during receive bursts. Use Value: 90% efficiency at 20mA extends battery life beyond 100 hours; 0.87V start-up ensures functionality until cell voltage drops below 0.9V per cell. |
Use Scenario: IR remote control using single AAA alkaline cell, needing regulated 3.3V for microcontroller and IR LED driver. IC Role / Device Role / Timing Role: Always-on boost converter operating in PFM mode during key-scan sleep (10µA load), switching to higher frequency under active transmit load. Use Value: 37µA quiescent current enables multi-year shelf life; shutdown mode (2µA) disables regulator when remote is stored. |
| Personal Medical Monitors | Single-Cell Battery-Powered Devices |
Use Scenario: Portable blood glucose meter powered by one CR2032 coin cell, requiring precise 3.3V for ADC and LCD bias. IC Role / Device Role / Timing Role: Precision voltage source with tight output tolerance (±3.5% over temp); supplies low-noise analog front-end. Use Value: Built-in power-fail comparator triggers early low-battery alert before measurement accuracy degrades; 2% hysteresis prevents chatter. |
Use Scenario: Wireless sensor node using single Li-ion cell (2.8V–4.2V), requiring adjustable 2.5V rail for ultra-low-power MCU. IC Role / Device Role / Timing Role: Configurable boost converter set to 2.5V via FB resistor network; operates across full battery range without reconfiguration. Use Value: Adjustable mode supports multiple voltage domains from one BOM; 5.5V max output headroom allows future firmware upgrades requiring higher VDD. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-up DC-DC converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS61200DRCT | Higher 300mA peak switch current; fixed 3.3V only; no integrated PFI/PFO comparator. | Lacks power-fail monitoring; requires external circuitry for brown-out detection in medical or industrial use. | Choose when higher output current (>50mA) is required and system-level fault detection is handled elsewhere. |
| LT1944ES5#TRMPBF | Wider input range (0.7V–5.5V); 85% max efficiency; no damping switch; SOT-23-5 package. | Lower integration - needs external Schottky diode and separate power-fail IC for equivalent functionality. | Prefer for cost-sensitive, lower-current (<20mA) applications where board area is less constrained than component count. |
Compared with TPS61200DRCT and LT1944ES5#TRMPBF, the MAX1678EUA+ uniquely combines ultra-low start-up voltage (0.87V), integrated power-fail detection, and EMI-suppressing damping switch in a single µMAX package - making it optimal for compact, battery-critical, and noise-sensitive portable systems.
Availability
MAX1678EUA+ is available at Aetrix Electronics and suitable for pagers, remote controls, personal medical monitors, and single-cell battery-powered devices requiring stable component supply, long-term lifecycle support, and guaranteed parametric performance across –40°C to +85°C.
Supply support for MAX1678EUA+ 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 semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, medical, and portable applications.
The MAX1678EUA+ belongs to Maxim's low-power DC-DC converter product line, designed specifically for energy-constrained battery-powered systems where start-up capability, quiescent current, and EMI control are critical system-level requirements.
FAQ
What is the minimum input voltage required for MAX1678EUA+ to start switching?
The MAX1678EUA+ guarantees start-up at 0.87V under defined conditions, verified across temperature and load. This is achieved via an internal low-voltage oscillator that pumps the output to ~1.7V before main regulation engages. Actual start-up voltage rises slightly with increasing load current - e.g., ~0.95V at 10mA - as shown in Figure MAX1678-15 of the datasheet. The MAX1678EUA+ remains operational even after start-up as input drops below 0.87V, provided output regulation can be maintained.
How does the MAX1678EUA+ achieve 90% efficiency with such low quiescent current?
The MAX1678EUA+ achieves high efficiency at light loads through pulse-frequency modulation (PFM), which reduces switching frequency as load decreases - minimizing gate-drive and switching losses. At heavier loads (e.g., 20mA), it maintains high duty-cycle operation with low-resistance internal switches (1Ω N-channel, 1.5Ω P-channel) and synchronous rectification. The 37µA quiescent current is measured at no load and does not compromise efficiency curves, which peak at 90% for 1.5V→3.3V conversion at 20mA - a balance enabled by its proprietary constant-peak-current control algorithm.
Can the MAX1678EUA+ operate with a 22µH inductor, and what trade-offs apply?
Yes, the MAX1678EUA+ supports 22µH inductors and delivers higher maximum output current (e.g., ~140mA at 3.3V with 1.2V input) compared to 47µH. However, lower inductance increases peak inductor current, output ripple, and EMI - requiring careful layout and possibly the external Schottky diode (Figure 3) for robust start-up under heavy load. Datasheet Figures MAX1678-16 through MAX1678-18 confirm performance across both values, but 47µH is recommended for best EMI and efficiency balance in most applications.
What is the function of the damping switch in the MAX1678EUA+, and how does it affect system design?
The damping switch in the MAX1678EUA+ connects the LX node to BATT during the dead time after synchronous rectifier turn-off, dissipating residual inductor energy and suppressing LC ringing. This reduces radiated EMI without altering output voltage ripple or requiring external snubbers. Layout must minimize LX trace inductance to maximize damping effectiveness - Figures 5 and 6 in the datasheet show measurable reduction in ringing amplitude and duration. No external components are needed to enable this feature.
How is power-fail detection implemented on the MAX1678EUA+, and what resistor values are recommended for a 2.0V threshold?
Power-fail detection uses the internal comparator referenced to 614mV at PFI. To set a 2.0V threshold, use R3 and R4 in a divider from OUT to GND, where R3 = R4 × ((VTH/VPFI) − 1). For VTH = 2.0V and VPFI = 0.614V, R3 ≈ 2.26 × R4. With R4 = 300kΩ (within 100kΩ–1MΩ recommended range), R3 = 678kΩ. PFI input current is ≤10nA, so resistor values do not significantly load the divider - ensuring accurate, stable threshold detection for the MAX1678EUA+.
MAX1678EUA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Up
- Output Configuration:
- Positive
- Topology:
- Boost
- Output Type:
- Adjustable (Fixed)
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 0.7V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 2V (3.3V)
- Voltage - Output (Max):
- 5.5V
- Current - Output:
- 550mA (Switch)
- Frequency - Switching:
- 150kHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-uMAX/uSOP
MAX1678EUA+ FAQ
1.How can I place an order for MAX1678EUA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1678EUA+ 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 MAX1678EUA+ reliable?
The price and inventory of MAX1678EUA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1678EUA+ is usually 5 days.
3.What payment methods are accepted for MAX1678EUA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1678EUA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1678EUA+?
MAX1678EUA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1678EUA+ 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 MAX1678EUA+?
For technical support, including MAX1678EUA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1678EUA+ requirements.
6.How does Aetrix verify that MAX1678EUA+ is sourced from the original manufacturer or authorized distributors?
All MAX1678EUA+ 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 MAX1678EUA+ meets industry standards.
7.What is the process for return or replacement of MAX1678EUA+?
All MAX1678EUA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX1678EUA+, 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 MAX1678EUA+ part is unused and in its original packaging.
Return procedure for MAX1678EUA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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