MAX258_13 Datasheet, PDF (1/12 Pages) Maxim Integrated Products – 500mA, Push-Pull Transformer Driver for Isolated Power Supplies

MAX258
EVALUATION KIT AVAILABLE
500mA, Push-Pull Transformer Driver
for Isolated Power Supplies
General Description
The MAX258 is a 500mA, push-pull transformer driver
designed to provide a simple solution for isolated power
supplies. The IC has an internal oscillator and operates
from a single +3.0V to +5.5V supply. The transformer’s
secondary-to-primary winding ratio defines the output
voltage, allowing selection of virtually any isolated output
voltage with galvanic isolation.
The device features an integrated oscillator driving a pair
of n-channel power switches. Internal circuitry guarantees
a fixed 50% duty cycle to prevent DC current flow through
the transformer.
The IC operates with up to 500mA of continuous current
and features undervoltage lockout and thermal shutdown.
The IC includes a low-current shutdown mode to reduce
the overall supply current to less than 5µA (max) when the
driver is disabled.
The MAX258 is available in a small 8-pin (2mm x 3mm)
TDFN package and is specified over the -40°C to +125°C
temperature range.
Typical Operating Circuit
Features and Benefits
● Simple, Flexible Design
• +3.0V to +5.5V Supply Range
• Low R_ON 300mΩ (max) at 4.5V
• Up to 90% Efficiency
• Provides Up to 500mA to the Transformer
• 250kHz or 600kHz Internal Oscillator Frequency
• -40ºC to +125ºC Temperature Range
● Integrated System Protection
• Undervoltage Lockout
• Thermal Shutdown
● Saves Space on Board
• Small 8-Pin TDFN Package (2mm x 3mm)
Applications
● Power Meter Data Interface
● Isolated Fieldbus Interface
● Medical Equipment
● Isolated Analog Front-End
Ordering Information appears at end of data sheet.
5V
HICLK
1µF
VDD
T2
1CT:1.3CT
MAX258
10µF
EN
T1
GND
PGND
1µF
ISOLATED
V_OUT
For related parts and recommended products to use with this part, refer to www.maximintegrated.com/MAX258.related.
19-6696; Rev 0; 5/13