MAX253ESA-T Datasheet, PDF (1/18 Pages) Maxim Integrated Products – MAX253 Transformer Driver for Isolated RS-485 Interface

AVAILABLE
MAX253
Transformer Driver for
Isolated RS-485 Interface
_______________General 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.
________________________Applications
Isolated RS-485/RS-232 Power-Supply
Transformer Driver
High Noise-Immunity Communications Interface
Isolated and/or High-Voltage Power Supplies
Bridge Ground Differentials
Medical Equipment
Process Control
__________Typi_Fc_ua_nl _cO_tp_ioe_nrat_li_Dng_iaC_grir_ac_mu_sit
ON / OFF
V_IN 5V
4
6
SD
V_CC
1
D1
MAX253
C1
OUTPUT
5V @ 200mA
C3
C2
3
FREQUENCY
SWITCH
FS
GND1
2
8
D2
GND2
7
____________________________Features
♦ Power-Supply Transformer Driver 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
______________Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
MAX253CPA
0°C to +70°C
8 Plastic DIP
MAX253CSA
0°C to +70°C
8 SO
MAX253CUA
0°C to +70°C
8 μMAX
MAX253C/D
0°C to +70°C
Dice*
MAX253EPA
-40°C to +85°C
8 Plastic DIP
MAX253ESA
-40°C to +85°C
8 SO
MAX253ESA/V
-40°C to +85°C
8 SO
MAX253MJA
-55°C to +125°C
8 CERDIP**
*Contact factory for dice specifications.
**Contact factory for availability and processing to MIL-STD-883.
Devices are also available in a lead(Pb)-free/RoHS-compliant
package. Specify lead-free by adding a (+) to the part number
when ordering.
/V Denotes an automotive qualified part.
Pin Configurations appear at end of data sheet.
Functional Diagrams continued at end of data sheet.
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For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
19-0226; Rev 2; 4/10