Information

Texas Instruments Signal Chain Guide 2013 | 123
Interface
Industrial – Digital Isolators
Get more information: www.ti.com/product/ISO1540,
www.ti.com/product/ISO1541
Get more information: www.ti.com/product/SN6501
Low-Power, Bidirectional I
2
C Isolators
ISO1540/1
Transformer Driver for Isolated Power Supplies
SN6501
The ISO1540 and ISO1541 are low-power, bidirectional isolators that are compatible
with I
2
C interfaces. These devices have their logic input and output buffers separated
by TI’s Capacitive Isolation technology using a silicon dioxide (SiO2) barrier. When used
in conjunction with isolated power supplies, these devices block high voltages, isolate
grounds, and prevent noise currents from entering the local ground and interfering with
or damaging sensitive circuitry.
The SN6501 is a monolithic oscillator/power-driver, specifically designed for small form
factor, isolated power supplies in isolated interface applications. It drives a low-profile,
center-tapped transformer primary from a 3.3 V or 5 V DC power supply. The secondary
can be wound to provide any isolated voltage based on transformer turns ratio.
The SN6501 consists of an oscillator followed by a gate drive circuit that provides the
complementary output signals to drive the ground referenced N-channel power switches.
The internal logic ensures break-before-make action between the two switches.
ISO1540 functional block diagram
SN6501 functional block diagram
Key Features
• Isolatedbidirectional,I
2
C compatible,
communications
•
Supportsupto1MHzoperation
• 3-Vto5.5-Vsupplyrange
• Opendrainoutputswith3.5-mAside
1 and 35-mA side 2 sink current
capability
•
–40°Cto125°Coperatingtemperature
• ±50kV/µstransientimmunity(typical)
• HBMESDprotectionof4kV
on all pins; 8 kV on bus pins
Applications
• IsolatedI
2
C Bus
®
• SMBusandPMBusinterfaces
• Open-drainnetworks
• Motorcontrolsystems
• Batterymanagement
• I
2
C level shifting
Key Features
• Push-pulldriverforsmalltransformers
• Single3.3Vor5Vsupply
High primary-side current drive:
5 V supply: 350 mA (max)
3.3 V supply: 150 mA (max)
• Lowrippleonrectifiedoutputpermits
small output capacitors
• Small5-pinSOT23package
Applications
• PLC/DCSI/Omodules:analoginput/
output, digital input
• Programmablelogiccontroller
• Solarmicro-andpowerinverters
1
2
3
4
6
5
8
7
SDA1
SCL1
GND1
SCL2
GND2
V
CC
1
V
CC
2
V
REF
V
REF
R
PU1b
R
PU1a
R
PU2a
SDA2
R
PU2b
OSC
Q
Q
SN6501
Gate
Drive
D1
V
CC
D2
GNDGND