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Analog Devices Inc./Maxim Integrated MAX1687ESA+
- Part No.:
- MAX1687ESA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX1687ESA+.pdf
- Description:
- IC REG BOOST ADJ 730MA 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,465
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Product details
Overview
MAX1687ESA+ from Maxim Integrated is a step-up DC-DC converter optimized for GSM burst-load applications, delivering up to 2W from 2.7V–6V input (single Li-Ion or three NiMH cells), featuring precise voltage-controlled current limit via LIM pin, 90% peak efficiency, and 3µA shutdown current. It reduces battery surge current by charging a reservoir capacitor between RF bursts, extending battery life and minimizing voltage sag in wireless handsets.
For engineers reviewing the MAX1687ESA+ datasheet, MAX1687ESA+ pinout, MAX1687ESA+ application, or MAX1687ESA+ equivalent, key selection criteria include its 8-pin SO package, adaptive current-limit configuration (distinct from MAX1688's CHG-based recharge control), 1.25V feedback reference, 450mA max peak battery current capability, and synchronized standby mode for RF noise suppression during transmit bursts.
Technical Context
The MAX1687ESA+ implements hysteretic inductor-current control with programmable peak current (via LIM pin: 0–1V → 0–460mA), internal synchronous rectification using integrated P- and N-channel MOSFETs (RDS(ON) = 0.7Ω / 0.8Ω), and four-phase soft-start (Linear Regulator → Pseudo Buck → Pseudo Boost → Boost) to limit inrush. Its feedback loop regulates output voltage to 1.25V at FB with 200µA/V transconductance (gmFB).
It operates with input undervoltage lockout at 2.7V, supports adjustable output from 1.25V to 6V via external resistor divider, and features output disconnect during shutdown. The ON pin enables synchronized standby mode (≥1.2ms low → 3µA shutdown), eliminating switching noise during RF transmission while allowing the reservoir capacitor to supply burst load current.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.7V to 6V - supports single Li-Ion (fully charged to depleted) or three NiMH/alkaline cells without external regulation. |
| Output Voltage Range | 1.25V to 6V - set externally via resistor divider on FB pin; regulated to 1.25V nominal reference. |
| Peak Battery Current | 450mA - limits surge draw during GSM burst loads, reducing battery stress and voltage sag. |
| Conversion Efficiency | Up to 90% - achieved via internal synchronous rectification, eliminating external Schottky diode and associated losses. |
| Shutdown Current | 3µA - ultra-low quiescent draw in shutdown mode, preserving battery during idle periods. |
| Feedback Reference Voltage | 1.25V ±3% - high-accuracy internal reference enabling stable output regulation across temperature (-40°C to +85°C). |
| Operating Temperature | -40°C to +85°C - qualified for industrial and mobile handset environments with no derating required. |
Pinout & Package
MAX1687ESA+ is housed in an 8-pin SO (Small Outline) package, 1.75mm body width, with gull-wing leads and standard JEDEC MS-012AC footprint. Pin 1 is marked with a beveled corner or dot.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 IN | Supply Input | Battery input (2.7V–6V); requires ≥47µF bypass capacitor to PGND for stability and transient response. |
| 2 LX1 | Inductor Switch Node (P-Channel Source) | Connects to one end of boost inductor; internal P-MOSFET source node - not directly accessible. |
| 3 FB | Feedback Input | Sense point for output voltage divider; regulates VOUT to 1.25V; high-impedance input (50nA typical bias). | 4 LX2 | Inductor Switch Node (N-Channel Drain) | Connects to other end of boost inductor; internal N-MOSFET drain - forms synchronous rectifier path with LX1. |
| 5 ON | Enable/Standby Control | Active-high logic input; ≥1.8V = normal operation, ≤0.6V = standby (inductor ramp-down), >1.2ms low = shutdown (3µA IQ). |
| 6 LIM | Current Limit Adjust | Voltage-controlled input (0–1V) sets peak battery current: ILIM = VLIM × 0.86A/V – 0.06A; clamped at 1.25V internally. |
| 7 REF | Reference Output | 1.25V ±3% buffered reference; supplies ≤10µA; usable for generating LIM voltage via resistor divider in TSSOP only (not used in SO variant). |
| 8 GND | Ground | Single ground pin serving analog (AGND) and power (PGND) functions - requires star grounding per layout guidelines. |
Key Features
| Feature | Design Value |
|---|---|
| Precise voltage-controlled current limit | LIM pin accepts 0–1V to linearly adjust peak battery current from 0 to 460mA - enables optimization of reservoir capacitor size vs. battery lifetime in GSM systems. |
| Internal synchronous rectification | Integrated P- and N-channel MOSFETs eliminate external Schottky diode, reducing component count and improving efficiency to >90% at 5V/300mA. |
| Four-phase soft-start | Linear Regulator → Pseudo Buck → Pseudo Boost → Boost sequence limits inrush current during power-up, preventing battery droop-induced system resets. |
| Synchronized standby mode | ON pin disables switching during RF transmit bursts, letting reservoir capacitor supply 2A GSM pulses while eliminating switching noise coupling into sensitive RF circuitry. |
| Output disconnect in shutdown | Internal switch isolates OUT from IN during shutdown, preventing reverse current flow and protecting downstream circuitry from backfeed. |
Applications
| GSM Mobile Handsets | Wireless LAN PC Cards (PCMCIA) |
|---|---|
|
Use Scenario: Powering RF power amplifier during 12% duty-cycle GSM transmit bursts requiring 2A peak at 5V. IC Role / Device Role / Timing Role: Step-up DC-DC converter with synchronized standby - active between bursts to recharge reservoir capacitor, disabled during bursts to supply clean power from capacitor. Use Value: Limits peak battery current to 450mA, reducing voltage sag by >150mV and extending Li-Ion cycle life by minimizing high-current stress. |
Use Scenario: Providing regulated 3.3V/5V to WLAN baseband ICs and PA in Type II PCMCIA cards with tight space constraints. IC Role / Device Role / Timing Role: Compact, high-efficiency boost converter with minimal external components - delivers 2W from 3.3V host bus or battery rail. Use Value: Enables full-power WLAN operation from single-cell Li-Ion without violating PCMCIA current limits (1A max per slot), thanks to reservoir-capacitor energy buffering. |
| Industrial Telematics Modules | Portable Medical Data Loggers |
|
Use Scenario: Supplying 5V to GPS/GSM combo modules in vehicle-mounted asset trackers operating from 3.6V Li-SOCl₂ primary battery. IC Role / Device Role / Timing Role: Burst-mode power manager - charges 2200µF reservoir cap during sleep, powers 1.5A GPS acquisition bursts for <500ms. Use Value: Maintains stable 5V output despite 3.6V→2.8V battery discharge, avoiding brownouts during critical location fixes. |
Use Scenario: Powering 3.3V ADC, microcontroller, and Bluetooth LE radio in battery-operated ECG loggers requiring 10-year shelf life. IC Role / Device Role / Timing Role: Low-quiescent boost regulator - delivers 3.3V from 1.5V alkaline cells, entering 3µA shutdown between 15-minute measurement cycles. Use Value: Extends alkaline battery life to >5 years by minimizing no-load current and enabling deep-sleep operation with zero output leakage. |
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 |
|---|---|---|---|
| MAX1688ESA+ | Replaces LIM pin with CHG pin for adaptive constant-recharge-time algorithm; uses output voltage droop to self-adjust peak inductor current. | Preferred for variable-input-voltage systems (e.g., aging Li-Ion) where reservoir recharge time must remain constant regardless of VIN or COUT tolerance. | Select MAX1688ESA+ when optimizing for longest possible battery life under varying discharge profiles; MAX1687ESA+ offers simpler fixed-current-limit design. |
| TPS61040DRVR | Fixed 0.5A current limit, no LIM/CHG pin; 500kHz fixed-frequency PWM (vs. MAX1687ESA+'s hysteretic control); lower 28µA quiescent current but no synchronized standby. | Suitable for constant-load applications (e.g., LCD bias) but lacks GSM burst-noise suppression capability and reservoir-capacitor management. | Choose TPS61040DRVR only for non-burst, low-IQ applications; MAX1687ESA+ remains superior for RF-sensitive GSM/WLAN designs requiring noise-free transmit windows. |
Compared with MAX1688ESA+, MAX1687ESA+ provides deterministic current limiting via analog voltage input rather than adaptive droop sensing - simplifying design validation but requiring manual LIM voltage calibration. Against TPS61040DRVR, MAX1687ESA+ delivers superior burst-mode performance with synchronized noise suppression and higher peak efficiency under pulsed loads.
Availability
MAX1687ESA+ is available at Aetrix Electronics and suitable for GSM handsets, wireless PC cards, and industrial telematics modules requiring stable component supply, long-lifecycle support, and guaranteed traceable sourcing for production programs.
Supply support for MAX1687ESA+ 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 MAX1687ESA+ belongs to Maxim's GSM-optimized power-management product line, designed specifically to solve battery surge-current and RF noise challenges in cellular handsets and burst-powered wireless devices.
FAQ
What is the maximum output current capability of the MAX1687ESA+?
The MAX1687ESA+ does not specify a fixed maximum output current; instead, it delivers up to 2W of power (e.g., 400mA at 5V or 333mA at 6V). Peak load current is determined by the reservoir capacitor size, input voltage, and programmed LIM voltage. At 5V output and 3.3V input, typical sustained output is 350mA, while GSM burst loads up to 2A are supported via capacitor discharge - the MAX1687ESA+ itself limits peak battery current to 450mA.
Can the MAX1687ESA+ be used with a single alkaline cell?
Yes, the MAX1687ESA+ supports input voltages from 2.7V to 6V, covering the full discharge range of three alkaline cells (4.5V fresh → 2.7V depleted). It has been validated in PCMCIA applications powered by triple-alkaline stacks. However, single alkaline (1.5V) falls below the 2.7V UVLO threshold and is not supported - use MAX1722/MAX1723 for 0.7V–5.5V input ranges instead.
How does the LIM pin function on the MAX1687ESA+?
The LIM pin on the MAX1687ESA+ accepts a 0–1V analog voltage to set peak battery current linearly: ILIM = VLIM × 0.86A/V – 0.06A. At 0V, current limit is 0A (disabled); at 1V, it reaches 460mA. The pin is internally clamped to 1.25V. In the 8-pin SO package (MAX1687ESA+), REF is not bonded out, so LIM voltage must be generated externally - e.g., via DAC or resistor divider from a separate reference.
Does the MAX1687ESA+ require an external Schottky diode?
No, the MAX1687ESA+ integrates both P-channel and N-channel MOSFETs for synchronous rectification, eliminating the need for an external Schottky diode. This improves conversion efficiency to over 90% and reduces board area and thermal dissipation. The internal MOSFETs have RDS(ON) of 0.7Ω (P-ch) and 0.8Ω (N-ch), optimized for 1–2MHz switching frequencies typical in GSM burst applications.
What is the purpose of the ON pin's 1.2ms timeout on the MAX1687ESA+?
The ON pin on the MAX1687ESA+ has a built-in 1.2ms timeout: if held low longer than this duration, the device enters shutdown mode with 3µA quiescent current. This allows a single control signal to manage both short-term standby (for RF burst noise suppression) and deep shutdown (for extended idle periods). During standby (<1.2ms low), inductor current ramps to zero and output disconnects; in shutdown, all internal circuits power down except the ON comparator.
MAX1687ESA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Last Time Buy
- Function:
- Step-Up
- Output Configuration:
- Positive
- Topology:
- Boost
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.7V
- Voltage - Input (Max):
- 6V
- Voltage - Output (Min/Fixed):
- 1.25V
- Voltage - Output (Max):
- 6V
- Current - Output:
- 730mA (Switch)
- Frequency - Switching:
- 1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX1687ESA+ FAQ
1.How can I place an order for MAX1687ESA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX1687ESA+ 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 MAX1687ESA+ reliable?
The price and inventory of MAX1687ESA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX1687ESA+ is usually 5 days.
3.What payment methods are accepted for MAX1687ESA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX1687ESA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX1687ESA+?
MAX1687ESA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX1687ESA+ 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 MAX1687ESA+?
For technical support, including MAX1687ESA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX1687ESA+ requirements.
6.How does Aetrix verify that MAX1687ESA+ is sourced from the original manufacturer or authorized distributors?
All MAX1687ESA+ 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 MAX1687ESA+ meets industry standards.
7.What is the process for return or replacement of MAX1687ESA+?
All MAX1687ESA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX1687ESA+, 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 MAX1687ESA+ part is unused and in its original packaging.
Return procedure for MAX1687ESA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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