Rainbow Electronics MAX13256 - Manual

MAX13256
36V H-Bridge Transformer
Driver for Isolated Supplies
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General Description
The MAX13256 H-bridge transformer driver provides a
simple solution for making isolated power supplies up to
10W. The device drives a transformer’s primary coil with
up to 300mA of current from a wide 8V to 36V DC sup-
ply. The transformer’s secondary-to-primary winding ratio
defines the output voltage, allowing selection of virtually
any isolated output voltage.
The device features adjustable current limiting, allowing
indirect limiting of secondary-side load currents. The cur-
rent limit of the MAX13256 is set by an external resistor. A
FAULT output asserts when the device detects an overtem-
perature or overcurrent condition. In addition, the device
features a low-power mode to reduce the overall supply
current to 0.65mA (typ) when the driver is not in use.
The device can be operated using the internal oscillator
or driven by an external clock to synchronize multiple
MAX13256 devices and precisely set the switching fre-
quency. Internal circuitry guarantees a fixed 50% duty
cycle to prevent DC current flow through the transformer,
regardless of which clock source is used.
The device is available in a small 10-pin (3mm x 3mm)
TDFN package and is specified over the -40NC to +125NC
automotive temperature range.
Benefits and Features
S Simple, Flexible Design

8V to 36V Supply Range
 Up to 90% Efficiency
 Provides Up to 10W to the Transformer
 Undervoltage Lockout
 2.5V to 5V Compatible Logic Interface
 Internal or External Clock Source
 Adjustable Overcurrent Threshold
S Integrated System Protection

Fault Detection and Indication
 Overcurrent Limiting
 Overtemperature Protection
S
Saves Space on Board

Small 10-Pin TDFN Package (3mm x 3mm)
Applications
Power Meters
Isolated Fieldbus Interfaces
24V PLC Supply Isolation
Medical Equipment
Motor Controls
Typical Operating Circuit
19-5847; Rev 1; 8/11
Ordering Information appears at end of data sheet.
For related parts and recommended products to use with this part, refer to: www.maxim-ic.com/MAX13256.related
E V A L U A T I O N K I T A V A I L A B L E
FAULT
1µF
0.1µF
+24V
4.6kI
R LIM
V DD
EN
CLK
ST2
GND
ST1
ITH
ISOLATED
V OUT
MAX13256
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.