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Isolated Transformer Driver for PCMCIA Applications

Internal Power MOSFETs Save Space and Deliver 750mW

Product Details

Key Features

Parametric specs for Transformer Drivers
VIN (V) (min) 2.5
VIN (V) (max) 6
Driver Output Resistance (Ω) (max) 4
Max. IOUT (A) 0.2
Topology Push-Pull
Switching Frequency (kHz) 860
IQ (mA) (max) 1.1
Package/Pins SOIC (N)/8
UMAX/8
Oper. Temp. (°C) -40 to +85
Budgetary
Price (See Notes)
2.48
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Simplified Block Diagram

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Parameters

Parametric specs for Transformer Drivers
VIN (V) (min) 2.5
VIN (V) (max) 6
Driver Output Resistance (Ω) (max) 4
Max. IOUT (A) 0.2
Topology Push-Pull
Switching Frequency (kHz) 860
IQ (mA) (max) 1.1
Package/Pins SOIC (N)/8
UMAX/8
Oper. Temp. (°C) -40 to +85
Budgetary
Price (See Notes)
2.48

Key Features

  • Transformer Driver for Ultra-Thin 5V-µs Transformers
  • Isolated DC-to-DC Power Supply for PCMCIA Applications
  • 450kHz Minimum Switching Frequency
  • Ultra-Low Input Supply Current Ripple
  • Single +5V or +3.3V Supply
  • 5µW Low-Power Shutdown Mode
  • 8-Pin SO and µMAX Packages
  • Low Output Ripple Permits Miniature Output Capacitors

Applications/Uses

  • Bridge Ground Differentials
  • Isolated Data Acquisition
  • Isolated Interface Power Supply
  • Low-Power LAN Networks
  • Medical Equipment
  • Noise-Immunity Communications Interface
  • PCMCIA Modem Cards
  • Process Control

Description

The MAX845 provides an isolated power supply small enough to fit in thin PCMCIA cards and space-sensitive applications. It drives a low-profile center-tapped transformer primary from a 5V or 3.3V DC power supply. The secondary can be wound to provide any isolated positive or negative voltage at powers up to 750mW.

The MAX845 consists of an oscillator followed by a toggle flip-flop. The flip-flop generates two 50% duty-cycle square waves, which are complementary at half the oscillator frequency (450kHz, min). These two signals drive the ground-referenced N-channel power switches. Internal circuitry ensures break-before-make action between the two switches.

A low-power shutdown disables both the switches and the oscillator, reducing power consumption. An evaluation kit (MAX845EVKIT-MM) is available to evaluate low-profile 5V 40mA and 5V 100mA applications.

Simplified Block Diagram

MAX845: Typical Operating Circuit MAX845: Typical Operating Circuit Zoom icon

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 .