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MAX22256/MAX22258
Product Highlights
Compact, 36V H-Bridge
Transformer Driver for Isolated
Supplies
Simplified Application Diagram
+24V
10µF
•
Simple, Flexible Design
• 5V to 36V Supply Range
0.1µF
• Up to 91% Efficiency
V
DD
EN
C
SRC
• Provides over 15W to Transformer
• Undervoltage Lockout
• Internal or External Clock Source
• Synchronous Clock Output (MAX22258)
• Programmable Overcurrent Threshold
• 30ns to 200ns Adjustable Deadtime (MAX22258)
CLKI
ST1
MAX22256B
MAX22256C
V
LOGIC
V
V
DD
GATE
FAULT
ITH
DRIVER
IC
ST2
SS
R
LIM
GND
ISO_GND
•
•
Robust Integrated System Protection
• Fault Detection and Indication
• Overcurrent Limiting up to 1A
Pin Description
• Over-Temperature Protection
• Precision Internal Clock Source (±6%) Prevents
Excessive Transformer Core Losses Due to
Frequency Shift
TOP VIEW
ST1 GND ST2 GND FAULT
10
9
8
7
6
• Wide Temperature Range: -40°C to +125°C
Space Savings
• Small 3mm x 3mm 10-Pin TDFN Package
(MAX22256A/B/C) with 0.5mm Pitch
• Small 4mm x 5mm 14-Pin TSSOP Package
(MAX22258) with 0.65mm Pitch
MAX22256
*EP
+
Key Applications
1
2
3
4
5
CLKI EN ITH
V
DD
V
DD
•
Isolated Motor Drive Gate Power Supply
TDFN-EP
3mm x 3mm
*EP = Exposed Pad. Connect to ground.
The MAX22256/MAX22258 family provides a simple
solution for making isolated power supplies over
15W. These devices drive a transformer’s primary
coil with up to 650mA
of current from a wide 5V
RMS
to 36V DC supply. The MAX22256B/C are optimized
for LLC-type resonant topology, improving efficiency,
and reducing switching noise.
A FAULT output alerts the main controller during an
over-temperature or over-current condition. These
devices feature a low-power mode to reduce the overall
supply current to 0.7mA (typ) when the driver is not in
use.
•
Isolated +24V PLC Field Supply
The MAX22256/MAX22258 family features
a
resistor-adjustable current limit that allows indirect
limiting of the secondary-side load current and
protects the primary power source in the event of
secondary- or field-side failure.
The device can be operated using the accurate internal
oscillator or driven by an external clock to synchronize
multiple devices and precisely set the switching
frequency.
Ordering Information appears at end of data sheet.
19-101440; Rev 1; 3/22
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