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1W Primary-Side Transformer H-Bridge Driver for Isolated Supplies

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) 350
IQ (mA) (max) 0.45
Package/Pins CDIP/8
PDIP/8
SOIC (N)/8
UMAX/8
Oper. Temp. (°C) -55 to +125
-40 to +85
0 to +70
Budgetary
Price (See Notes)
1.66
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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) 350
IQ (mA) (max) 0.45
Package/Pins CDIP/8
PDIP/8
SOIC (N)/8
UMAX/8
Oper. Temp. (°C) -55 to +125
-40 to +85
0 to +70
Budgetary
Price (See Notes)
1.66

Key Features

  • Simple Power-Supply Transformer Driver Design for Isolated RS-485/RS-232 Data-Interface Applications
    • Single 5V or 3.3V Supply
    • Low-Current Shutdown Mode: 0.4µA
    • Pin-Selectable Frequency: 350kHz or 200kHz
  • 8-Pin DIP, SO, and µMAX® Packages Take Minimal Board Space

Applications/Uses

  • Bridge Ground Differentials
  • High Noise-Immunity Communications Interface
  • Isolated and/or High-Voltage Power Supplies
  • Isolated RS-485/RS-232 Power Supply
  • Medical Equipment
  • Process Control
  • Transformer Driver

Description

The MAX253 monolithic oscillator/power-driver is specifically designed to provide isolated power for an isolated RS-485 or RS-232 data interface. The device drives a center-tapped transformer primary from a 5V or 3.3V DC power supply. The secondary can be wound to provide any isolated voltage needed at power levels up to 1W.

The MAX253 consists of a CMOS oscillator driving a pair of N-channel power switches. The oscillator runs at double the output frequency, driving a toggle flip-flop to ensure 50% duty cycle to each of the switches. Internal delays are arranged to ensure break-before-make action between the two switches.

The SD pin puts the entire device into a low-power shutdown state, disabling both the power switches and oscillator.

Simplified Block Diagram

MAX253: Typical Operating Circuit MAX253: 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 .