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Analog Devices Inc./Maxim Integrated MAX1842EEE+
- Part No.:
- MAX1842EEE+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
MAX1842EEE+.pdf
- Description:
- IC REG BUCK ADJ 1A 16QSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,099
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Product details
Overview
MAX1842EEE+ from Maxim Integrated is a synchronous step-down DC-DC regulator with internal PMOS/NMOS switches, delivering up to 2.7A burst output current at 1MHz switching frequency. It operates from 3.0V–5.5V input and supports pin-selectable 1.5V/1.8V/2.5V or adjustable 1.1V–VIN outputs. Designed for CPU I/O ring and chipset supplies in notebook computers, it achieves up to 95% efficiency with no external Schottky diode required.
For engineers reviewing the MAX1842EEE+ datasheet, MAX1842EEE+ pinout, MAX1842EEE+ application, or MAX1842EEE+ equivalent, key selection considerations include its 3.1A min current limit, 16-pin QSOP package, Idle Mode™ light-load optimization, 100% duty-cycle low-dropout operation, and programmable constant-off-time control for frequency tuning between ~270kHz and 1MHz.
Technical Context
The MAX1842EEE+ uses a current-mode, constant-off-time PWM architecture that dynamically adjusts on-time while holding off-time fixed via RTOFF, enabling fast line/load transient response and inherent frequency stability under varying input conditions. Its proprietary Idle Mode™ skips switching cycles below 0.2–1.0A load thresholds to minimize gate-charge and transition losses.
It integrates a 90mΩ PMOS high-side switch and 70mΩ NMOS synchronous rectifier (at VIN = 4.5V), eliminating external diode conduction loss. Thermal shutdown (160°C) and output short-circuit protection are built-in, with soft-start controlled by an external capacitor on SS pin and feedback voltage set via FBSEL logic state or resistive divider.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.0V to 5.5V - supports direct regulation from common 3.3V/5V rails without pre-regulation. |
| Output Voltage Options | Pin-selectable 1.5V/1.8V/2.5V or adjustable 1.1V–VIN - enables flexible core/I/O rail generation without external resistor networks for fixed outputs. |
| Continuous Output Current | 1A - sufficient for sustained loads like chipset power domains in subnotebooks. |
| Burst Output Current | 2.7A - handles transient CPU I/O ring current spikes without dropout or thermal shutdown. |
| Switching Frequency | Up to 1MHz - allows use of small inductors (e.g., 1.5μH–2.5μH) and compact ceramic output capacitors. |
| Efficiency | Up to 95% - achieved via synchronous rectification and low RDS(ON) internal switches, reducing heat dissipation in space-constrained designs. |
| Shutdown Supply Current | <1μA - enables ultra-low-power system sleep states without battery drain. |
Pinout & Package
MAX1842EEE+ is housed in a 16-pin QSOP (Quarter-Size Outline Package) with exposed pad for thermal enhancement. Pin pitch is 0.025", body dimensions 3.9mm × 4.9mm × 1.35mm (JEDEC MO-137AC). The package supports standard reflow profiles and provides adequate thermal performance when mounted on ≥0.5in² copper area.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 SHDN | Logic-level shutdown control | Drives internal circuitry and MOSFETs into <1μA quiescent state; compatible with 0.8V/2.0V logic thresholds. |
| 2,4 IN | Main power input | Supplies internal PMOS switch; requires local 33μF low-ESR input capacitor per datasheet recommendation. |
| 3,14,16 LX | Switch node | Connects drains of internal PMOS and NMOS switches; interfaces directly to inductor and output filter. |
| 5 SS | Soft-start timing | External capacitor sets inrush current ramp rate; prevents input supply sag during startup. |
| 6 COMP | Integrator compensation | 470pF capacitor to VCC stabilizes control loop; critical for transient response and phase margin. |
| 7 TOFF | Off-time programming | Resistor to GND (36kΩ–430kΩ) sets tOFF, determining max switching frequency up to 1MHz. |
| 8 FB | Feedback input | Monitors output voltage directly (fixed mode) or via resistive divider (adjustable mode); reference is 1.1V ±1.2%. |
| 9 GND | Analog ground | Reference for internal error amplifier and comparator; must be separated from PGND in layout. |
| 10 REF | Internal 1.1V reference output | Bypassed with 1μF capacitor; used as precision reference for FB divider in adjustable configurations. |
| 11 FBSEL | Output voltage select | Logic state (GND/REF/VCC/floating) selects 1.5V/1.8V/2.5V or adjustable mode per Table 3. |
| 12 VCC | Analog supply | Internally regulated analog rail; bypassed with 10Ω + 2.2μF RC filter to suppress noise coupling. |
| 13,15 PGND | Power ground | Return path for NMOS switch current; tied internally to LX source; requires low-inductance connection to input/output caps. |
Key Features
| Feature | Design Value |
|---|---|
| ±1% output voltage accuracy | Ensures stable core voltage for sensitive digital logic without post-regulation trimming. |
| Idle Mode™ light-load optimization | Maintains >85% efficiency at 10mA load by skipping pulses-critical for battery runtime in standby. |
| Programmable constant-off-time control | Enables precise trade-off between EMI (lower fSW), component size (higher fSW), and efficiency across input/output combinations. |
| 100% duty-cycle low-dropout operation | Permits regulation down to VOUT = VIN − IOUT × 90mΩ - extends usable input range near battery end-of-discharge. |
| Integrated 90mΩ PMOS / 70mΩ NMOS switches | Eliminates external Schottky diode and associated BOM cost, footprint, and thermal management overhead. |
| Adjustable soft-start with external capacitor | Prevents input surge currents exceeding 3A during cold start-protects upstream regulators and connectors. |
Applications
| CPU I/O Ring Power | Chipset Core Supply |
|---|---|
Use Scenario: Delivering stable 1.5V/1.8V to Intel/AMD chipset I/O buffers during dynamic bus activity with rapid current transients up to 2.5A. IC Role / Device Role / Timing Role: Primary synchronous buck regulator providing tightly regulated, low-noise power with fast transient response. Use Value: 2.7A burst capability and 10μs load-step recovery prevent I/O timing violations during memory access bursts. |
Use Scenario: Generating 2.5V core voltage for northbridge/southbridge logic in subnotebook platforms with strict thermal envelope limits. IC Role / Device Role / Timing Role: High-efficiency point-of-load converter operating continuously at 1A with minimal heatsink requirement. Use Value: 95% peak efficiency and 16-pin QSOP package enable compact, fanless motherboard designs. |
| Notebook System Rail | Low-Voltage Peripheral Interface |
Use Scenario: Converting 5V main rail to 1.1V–1.5V for embedded controller (EC) or touchpad ASIC in clamshell laptops. IC Role / Device Role / Timing Role: Adjustable-output buck regulator supporting multiple firmware-configurable voltage levels. Use Value: Pin-selectable presets and resistor-divider flexibility simplify BOM management across product variants. |
Use Scenario: Powering USB 3.0 PHY, PCIe endpoint, or eMMC interface requiring clean, ripple-free 1.8V at ≤500mA. IC Role / Device Role / Timing Role: Low-noise, high-PSRR DC-DC converter with integrated filtering and soft-start sequencing. Use Value: 1MHz operation minimizes EMI interference with high-speed serial links; <1μA shutdown preserves battery life during suspend. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX1742EEE+ | Lower 1.3A min current limit; optimized for 1A continuous loads with smaller external components. | Better suited for low-power chipset rails where burst current demand is absent. | Select MAX1742EEE+ when design requires lower peak current capability and tighter board area constraints. |
| MAX1623EEE+ | 3A continuous output; uses different control architecture (voltage-mode PWM); no Idle Mode; larger 20-pin TSSOP package. | Targeted at higher-power applications like graphics subsystems where sustained >2A delivery is mandatory. | Choose MAX1623EEE+ only if continuous 3A output and legacy voltage-mode control are required-no drop-in replacement. |
Compared with MAX1742EEE+ and MAX1623EEE+, the MAX1842EEE+ uniquely balances 2.7A burst capability, 1MHz programmability, and Idle Mode efficiency-making it optimal for thermally constrained, battery-sensitive notebook I/O power where transient headroom matters more than continuous rating.
Availability
MAX1842EEE+ is available at Aetrix Electronics and suitable for notebook computer power management, chipset supply regulation, and CPU I/O ring applications requiring stable component supply, lead-free compliance, and long-term industrial availability.
Supply support for MAX1842EEE+ 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 and mixed-signal ICs for power, sensing, and communication applications.
The MAX1742/MAX1842 product line was designed specifically for high-efficiency, space-constrained DC-DC conversion in portable computing systems-emphasizing synchronous rectification, light-load optimization, and seamless integration with Intel/AMD platform power architectures.
FAQ
What is the maximum continuous output current supported by the MAX1842EEE+?
The MAX1842EEE+ delivers up to 1A of continuous output current under normal operating conditions. Its higher 2.7A burst rating applies only for short-duration transients (e.g., CPU I/O activity), not steady-state loads. Continuous operation above 1A risks thermal shutdown due to internal power dissipation limits in the 16-pin QSOP package.
How does the MAX1842EEE+ achieve 95% efficiency without an external Schottky diode?
The MAX1842EEE+ achieves 95% efficiency by integrating a low-RDS(ON) 70mΩ NMOS synchronous rectifier switch that replaces the lossy forward voltage drop of a Schottky diode. Combined with a 90mΩ PMOS high-side switch and Idle Mode™ light-load optimization, conduction and switching losses are minimized across the full load range.
Can the MAX1842EEE+ operate with input voltage equal to the output voltage?
Yes-the MAX1842EEE+ supports 100% duty-cycle operation when VIN approaches VOUT, maintaining regulation down to VOUT = VIN − IOUT × 90mΩ. This low-dropout behavior is enabled by the internal PMOS switch remaining fully enhanced, making it suitable for battery-powered systems nearing end-of-discharge.
What is the purpose of the TOFF pin on the MAX1842EEE+ and how is it configured?
The TOFF pin on the MAX1842EEE+ sets the constant off-time period that determines maximum switching frequency. A resistor (36kΩ–430kΩ) connected from TOFF to GND programs tOFF between 0.4μs and 4μs, enabling frequency tuning from ~270kHz to 1MHz. This allows designers to optimize for EMI, inductor size, or efficiency based on specific application requirements.
Does the MAX1842EEE+ require external compensation components for stable operation?
Yes-the MAX1842EEE+ requires a 470pF capacitor connected between COMP and VCC for loop stability. This capacitor sets the dominant pole of the transconductance amplifier integrator. Omitting or mis-sizing this component causes oscillation or poor transient response. Layout best practices mandate short, low-inductance traces to minimize noise coupling into the COMP node.
MAX1842EEE+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 16-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable (Programmable)
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 1.1V (1.5V, 1.8V, 2.5V)
- Voltage - Output (Max):
- 5.5V
- Current - Output:
- 1A
- Frequency - Switching:
- 1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-QSOP
MAX1842EEE+ FAQ
1.How can I place an order for MAX1842EEE+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1842EEE+ 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 MAX1842EEE+ reliable?
The price and inventory of MAX1842EEE+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1842EEE+ is usually 5 days.
3.What payment methods are accepted for MAX1842EEE+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1842EEE+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1842EEE+?
MAX1842EEE+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1842EEE+ 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 MAX1842EEE+?
For technical support, including MAX1842EEE+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1842EEE+ requirements.
6.How does Aetrix verify that MAX1842EEE+ is sourced from the original manufacturer or authorized distributors?
All MAX1842EEE+ 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 MAX1842EEE+ meets industry standards.
7.What is the process for return or replacement of MAX1842EEE+?
All MAX1842EEE+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX1842EEE+, 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 MAX1842EEE+ part is unused and in its original packaging.
Return procedure for MAX1842EEE+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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