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Analog Devices Inc./Maxim Integrated MAX1705ESE+
- Part No.:
- MAX1705ESE+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- -
- Datasheet:
-
MAX1705ESE+.pdf
- Description:
- IC REG BOOST ADJUSTABLE 1A
- Quantity:
- Payment:
- Shipping:
Inventory:2,480
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Product details
Overview
MAX1705ESE+ from Maxim Integrated is a high-efficiency, low-noise, synchronous step-up DC-DC converter with integrated 200mA LDO linear regulator and 1A n-channel MOSFET switch. It generates adjustable 2.5V–5.5V boost output from 1–3 NiCd/NiMH or 1 Li-Ion cell (0.7V–3.6V input), supports PWM/PFM mode selection via CLK/SEL, and delivers up to 850mA at 3.3V output in PWM mode for RF power amplifier supply in wireless handsets.
For engineers reviewing the MAX1705ESE+ datasheet, MAX1705ESE+ pinout, MAX1705ESE+ application, or MAX1705ESE+ equivalent, this device is selected for battery-powered portable instruments requiring dual-rail power (noisy switching + ultra-low-noise analog rail), pushbutton on/off control, track-mode efficiency optimization, and guaranteed 1.1V startup voltage across temperature.
Technical Context
The MAX1705ESE+ integrates a synchronous rectified PWM/PFM boost controller with an internal 1A n-channel MOSFET and 270mΩ p-channel synchronous rectifier, enabling up to 96% efficiency and 5% gain over nonsynchronous designs. Its dual-mode operation-300kHz fixed-frequency PWM for low-noise full-power delivery and variable-frequency PFM for <140µA quiescent current at light loads-is controlled directly by the CLK/SEL pin.
It features a dedicated track-mode function (TRACK pin) that dynamically sets the boost output 300mV above the LDO output voltage, reducing power loss in the linear regulator stage. The built-in 200mA LDO uses a 0.5Ω p-channel pass transistor with 1.25V reference and FBLDO feedback, delivering ultra-low-noise power to sensitive analog circuitry such as IF stages and LNAs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Boost Output Range | 2.5V to 5.5V adjustable via FB resistor divider; regulates to 1.233V at FB pin. |
| LDO Output Range | 1.25V to 5.0V adjustable via FBLDO divider; regulates to 1.250V at FBLDO pin. |
| Max Boost Output Current | 850mA at 3.3V (PWM mode, VIN ≥ 2.4V); limited by 1.55A internal n-MOSFET current limit. |
| Startup Input Voltage | Guaranteed 1.1V at +25°C; operates down to 0.7V once regulated (bootstrapped from OUT). |
| Quiescent Current | 190µA in low-power PFM mode; 1µA in shutdown mode (ONA=low, ONB=high). |
| Switching Frequency | 300kHz PWM mode (CLK/SEL = high); synchronizable to 200–400kHz external clock. |
| LDO Dropout Resistance | 0.5Ω typical; enables <100mV dropout at 200mA load for stable low-noise biasing. |
Pinout & Package
MAX1705ESE+ is housed in a 16-pin QSOP package (5.3mm × 10.2mm), pin-compatible with industry-standard 16-pin SOIC footprints but with reduced height. The package supports thermal dissipation up to 696mW at +70°C ambient (derating 8.7mW/°C above).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| LBP (Pin 1) | Low-battery comparator noninverting input | Sets low-battery threshold; common-mode range 0.5V–1.5V; 16mV hysteresis prevents chatter. |
| LBN (Pin 2) | Low-battery comparator inverting input | Compares against LBP; used with external resistive divider to trigger LBO open-drain alert. |
| REF (Pin 3) | 1.250V precision reference output | Sources ≤50µA; requires 0.33µF bypass capacitor for stability and noise rejection. |
| TRACK (Pin 4) | Track-mode control input | When tied to OUT, forces POUT = VLDO + 300mV-reducing LDO conduction loss and improving system efficiency. |
| GND (Pin 5) | Analog and digital ground reference | Common return for FB, FBLDO, CLK/SEL, ONA, ONB; must be low-impedance connection to PGND plane. |
| OUT (Pin 6) | IC power and LDO input | Supplies internal circuitry and LDO pass transistor; bypass with 0.1µF ceramic capacitor near IC. |
| FB (Pin 7) | Boost converter feedback input | Regulates POUT to 1.233V; connects to resistor divider between POUT and GND for output setting. |
| FBLDO (Pin 8) | LDO feedback input | Regulates LDO to 1.250V; connects to resistor divider between LDO and GND for output setting. |
| LDO (Pin 9) | LDO linear regulator output | Delivers up to 200mA; requires 22µF low-ESR (≤1Ω) output capacitor for stability per C6 ESR curve. |
| LBO (Pin 10) | Low-battery open-drain output | N-channel open-drain; pulls low when LBP < LBN; sinks ≥1mA at 0.4V max VOL; requires external pull-up. |
| CLK/SEL (Pin 11) | Mode selection & sync input | Low = PFM (low IQ); high = PWM (300kHz, low noise); external clock = synchronized PWM (200–400kHz). |
| PGND (Pin 12) | Power ground for n-MOSFET source | Separate from analog GND; must be connected to high-current inductor return path to minimize noise coupling. |
| LX (Pin 13) | Inductor switch node | Connects to inductor and Schottky diode cathode; drives internal n-MOSFET drain and p-MOSFET source. |
| ONB (Pin 14) | Off-control input | High + ONA low = shutdown; tied to GND for normal operation; hysteresis ~0.15×VOUT. |
| ONA (Pin 15) | On-control input | High or ONB low = enable; tied to OUT for push-on/push-off button control; hysteresis ~0.15×VOUT. |
| POUT (Pin 16) | Boost converter power output | Source of p-channel synchronous rectifier; supplies LDO and external loads; current shared with LDO draw. |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectification | Internal 270mΩ p-channel rectifier improves efficiency by 5% vs. diode-based boost converters. |
| Track-mode efficiency optimization | Reduces LDO conduction loss by dynamically aligning POUT 300mV above VLDO-critical for battery runtime extension. |
| Dual shutdown control (ONA/ONB) | Enables momentary pushbutton on/off and microprocessor-controlled enable without external logic. |
| Guaranteed 1.1V startup | CMOS low-voltage oscillator ensures reliable power-up from deeply discharged batteries (e.g., 1-cell Li-Ion at end-of-life). |
| Integrated low-battery comparator | Uncommitted LBN/LBP inputs with 16mV hysteresis allow flexible battery monitoring without external components. |
| Ultra-low shutdown current | 1µA shutdown IQ preserves battery charge during long storage or standby periods in portable devices. |
Applications
| Wireless Handset RF Power Supply | Digital Cordless Phone Base Station |
|---|---|
|
Use Scenario: Powering 3.3V RF power amplifier in GSM/PCS handset where battery voltage drops from 4.2V to 2.7V during discharge. IC Role / Device Role / Timing Role: Dual-rail source: POUT supplies PA bias; LDO supplies low-noise VCO/IF stage with <50µV RMS ripple. Use Value: Track mode maintains minimal LDO dropout across battery range, extending talk time by 12% vs. fixed-output boost + LDO. |
Use Scenario: Providing clean 3.3V and 5.0V rails in cordless phone base station with AC adapter and backup battery. IC Role / Device Role / Timing Role: Primary DC-DC converter for battery backup path; LDO filters switching noise from crystal oscillator and codec analog sections. Use Value: 96% peak efficiency and 1µA shutdown reduce heat buildup and extend backup runtime by >30 minutes under load. |
| Palmtop Computer LCD Backlight Driver | Two-Way Pager Audio Amplifier Bias |
|
Use Scenario: Driving white LED backlight requiring 4.5V @ 150mA from single 3.6V Li-Ion cell with tight space constraints. IC Role / Device Role / Timing Role: Step-up converter (POUT = 4.5V) powers LED string; LDO (LDO = 3.3V) supplies microcontroller core and touch controller. Use Value: Synchronous rectification and PFM mode reduce no-load current to 190µA-extending idle battery life to >72 hours. |
Use Scenario: Supplying 2.5V bias to audio power amplifier in compact pager where EMI must avoid 455kHz IF band. IC Role / Device Role / Timing Role: Synchronized PWM mode (CLK/SEL driven at 380kHz) places switching harmonics outside critical IF window. Use Value: External clock synchronization eliminates audible beat interference in speaker output while maintaining 85% efficiency. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-up DC-DC converter with integrated LDO applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX1706ESE+ | 0.5A n-MOSFET switch (vs. 1A); 950mA max inductor limit; lower POUT current capability. | Targeted at lower-power applications (e.g., pagers, handheld instruments) where 850mA is unnecessary. | Select MAX1706ESE+ when system load peaks ≤400mA and board layout prioritizes lower thermal density. |
| TPS61088RHLR | Higher 5.5A switch current; 2.7V–12V input; no integrated LDO; requires external post-regulator for low-noise rail. | Used in higher-input-voltage systems (e.g., 2-cell Li-Ion, USB-PD) where discrete LDO flexibility is preferred. | Choose TPS61088RHLR only if LDO requirements are met externally and input voltage exceeds 3.6V. |
Compared with MAX1706ESE+, MAX1705ESE+ delivers 2× higher boost output current and better light-load efficiency via optimized PFM control; compared with TPS61088RHLR, it integrates a matched LDO with track mode-eliminating design complexity and component count for dual-rail portable RF systems.
Availability
MAX1705ESE+ is available at Aetrix Electronics and suitable for wireless handsets, digital cordless phones, and palmtop computers requiring stable component supply, guaranteed -40°C to +85°C operation, and long-term production continuity.
Supply support for MAX1705ESE+ 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 portable, industrial, and communications applications.
The MAX1705/MAX1706 product line was designed specifically for battery-powered wireless instruments needing tightly coupled, low-noise dual-rail power-combining efficient boost conversion with linear post-regulation in a single QSOP package.
FAQ
What is the minimum input voltage required to start up the MAX1705ESE+?
The MAX1705ESE+ guarantees startup from 1.1V at +25°C using its internal low-voltage oscillator. Once regulation is achieved, it continues operating down to 0.7V input due to bootstrapped power from the OUT pin. This makes MAX1705ESE+ suitable for deeply discharged single-cell Li-Ion or multi-cell NiMH battery applications where conventional boost converters fail to start.
How does the TRACK pin improve system efficiency in the MAX1705ESE+?
When the TRACK pin is connected to the OUT pin, the MAX1705ESE+ configures the boost converter to regulate POUT to exactly VLDO + 300mV. This minimizes the voltage drop across the LDO's p-channel pass transistor, reducing conduction loss and heat generation-especially critical during high-LDO-current conditions. This track mode directly extends battery runtime in portable devices powered by MAX1705ESE+.
Can the MAX1705ESE+ drive both the RF power amplifier and baseband processor in a wireless handset?
Yes-the MAX1705ESE+ is explicitly designed for this dual-rail architecture. Its POUT pin delivers up to 850mA at 3.3V (PWM mode) to power noisy RF circuitry, while its integrated LDO provides up to 200mA of ultra-low-noise 3.3V or 2.5V power to sensitive analog/baseband sections. The separation of switching and linear paths within one IC simplifies PCB layout and reduces EMI coupling in wireless handsets using MAX1705ESE+.
What is the purpose of the ONA and ONB pins on the MAX1705ESE+?
ONA and ONB provide dual independent enable controls for pushbutton-driven on/off sequencing. When ONA is pulled high (e.g., tied to OUT), the device turns on; when ONB is pulled high while ONA is low, it shuts down. This allows direct integration of mechanical momentary switches without external logic-enabling true push-on/push-off functionality in battery-powered devices using MAX1705ESE+.
Does the MAX1705ESE+ require external compensation components for stability?
No external compensation is needed for the boost converter-the MAX1705ESE+ uses internal compensation. However, the LDO requires a 22µF output capacitor with ≤1Ω ESR (per Typical Operating Characteristics graph TOC11) for stability across 0–200mA load. Additionally, a 0.1µF ceramic capacitor must be placed close to the OUT pin, and 0.33µF capacitors are required at REF and C5 (LDO bypass) to ensure low-noise operation and PSRR performance in MAX1705ESE+ designs.
MAX1705ESE+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- -
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Up
- Output Configuration:
- Positive
- Topology:
- Boost
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 0.9V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 2.5V
- Voltage - Output (Max):
- 5.5V
- Current - Output:
- 1A (Switch)
- Frequency - Switching:
- 260kHz ~ 340kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
MAX1705ESE+ FAQ
1.How can I place an order for MAX1705ESE+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1705ESE+ 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 MAX1705ESE+ reliable?
The price and inventory of MAX1705ESE+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1705ESE+ is usually 5 days.
3.What payment methods are accepted for MAX1705ESE+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1705ESE+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1705ESE+?
MAX1705ESE+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1705ESE+ 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 MAX1705ESE+?
For technical support, including MAX1705ESE+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1705ESE+ requirements.
6.How does Aetrix verify that MAX1705ESE+ is sourced from the original manufacturer or authorized distributors?
All MAX1705ESE+ 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 MAX1705ESE+ meets industry standards.
7.What is the process for return or replacement of MAX1705ESE+?
All MAX1705ESE+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX1705ESE+, 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 MAX1705ESE+ part is unused and in its original packaging.
Return procedure for MAX1705ESE+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MAX1705ESE+ Tags
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