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1 to 3 Cell, High Current, Low-Noise, Step-Up DC-DC Converters with Linear Regulator

Low-Noise, Dual-Output Converter Powers PA and Radio Baseband and Logic In Cellular Phones

Product Details

Key Features

Parametric specs for Step-Down/Up Switching Regulators
VIN (V) (min) 0.7
VIN (V) (max) 5.5
VOUT1 (V) (min) 2.5
VOUT1 (V) (max) 5.5
IOUT1 (A) (max) 0.8
Switch Type Internal
Output Adjust. Method Resistor
Synchronous Switching? Yes
Power Good Signal Yes
ICC (mA) (max) 0.19
# DC-DC Outputs 1
Alternate Topology Step-Up
# LDO/ Op.Amp. Outputs 1
Switching Frequency (kHz) 400
Package/Pins QSOP/16
Oper. Temp. (°C) -40 to +85
Budgetary
Price (See Notes)
4.11
Parametric specs for Step-Up Switching Regulators
VIN (V) (min) 0.7
VIN (V) (max) 5.5
VOUT1 (V) (min) 2.5
VOUT1 (V) (max) 5.5
IOUT1 (A) (max) 0.8
Switch Type Internal
Output Adjust. Method Resistor
Power Good Signal Yes
Synchronous Switching? Yes
ICC (mA) (typ) 0.1
Shutdown Mode Supply Current (µA) (typ) 1
Shutdown Mode Supply Current (µA) (max) 20
# DC-DC Outputs 1
Switching Frequency (kHz) 400
Package/Pins QSOP/16
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Simplified Block Diagram

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Parameters

Parametric specs for Step-Down/Up Switching Regulators
VIN (V) (min) 0.7
VIN (V) (max) 5.5
VOUT1 (V) (min) 2.5
VOUT1 (V) (max) 5.5
IOUT1 (A) (max) 0.8
Switch Type Internal
Output Adjust. Method Resistor
Synchronous Switching? Yes
Power Good Signal Yes
ICC (mA) (max) 0.19
# DC-DC Outputs 1
Alternate Topology Step-Up
# LDO/ Op.Amp. Outputs 1
Switching Frequency (kHz) 400
Package/Pins QSOP/16
Oper. Temp. (°C) -40 to +85
Budgetary
Price (See Notes)
4.11
Parametric specs for Step-Up Switching Regulators
VIN (V) (min) 0.7
VIN (V) (max) 5.5
VOUT1 (V) (min) 2.5
VOUT1 (V) (max) 5.5
IOUT1 (A) (max) 0.8
Switch Type Internal
Output Adjust. Method Resistor
Power Good Signal Yes
Synchronous Switching? Yes
ICC (mA) (typ) 0.1
Shutdown Mode Supply Current (µA) (typ) 1
Shutdown Mode Supply Current (µA) (max) 20
# DC-DC Outputs 1
Switching Frequency (kHz) 400
Package/Pins QSOP/16

Key Features

  • Up to 96% Efficiency
  • 1.1VIN Guaranteed Startup
  • Up to 850mA Output (MAX1705)
  • Step-Up Output (2.5V to 5.5V Adjustable)
  • Linear Regulator (1.25V to 5.0V Adjustable)
  • PWM/PFM Synchronous-Rectified Topology
  • 300kHz PWM Mode or Synchronizable
  • 1µA Shutdown Mode
  • Voltage Monitor
  • Pushbutton On/Off Control

Applications/Uses

  • Digital Cordless Phones
  • Handheld Instruments (PDAs, Palmtops)
  • Palmtop Computers
  • PCS Phones
  • Personal Communicators
  • Two-Way Paging
  • Wireless Handsets

Description

The MAX1705/MAX1706 are high-efficiency, low-noise, step-up DC-DC converters with an auxiliary linear-regulator output. These devices are intended for use in battery-powered wireless applications. They use a synchronous rectifier pulse-width-modulation (PWM) boost topology to generate 2.5V to 5.5V outputs from battery inputs, such as 1 to 3 NiCd/NiMH cells or 1 Li-Ion cell. The MAX1705 has an internal 1A n-channel MOSFET switch. The MAX1706 has a 0.5A switch. Both devices also have a built-in low-dropout linear regulator that delivers up to 200mA.

With an internal synchronous rectifier, the MAX1705/MAX1706 deliver 5% better efficiency than similar non-synchronous converters. They also feature a pulse-frequency-modulation (PFM) standby mode to improve efficiency at light loads, and a 1µA shutdown mode. An efficiency-enhancing track mode reduces the step-up DC-DC converter output to 300mV above the linear-regulator output.

Both devices come in a 16-pin QSOP package, which occupies the same space as an 8-pin SO. Other features include two shutdown-control inputs for push-on/push-off control, and an uncommitted comparator for use as a voltage monitor.

Simplified Block Diagram

 

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .