1
dc1986af
DEMO MANUAL DC1986A
DESCRIPTION
LTM2892-I
I
2
C µModule Isolator
Demonstration circuit 1986A is an I
2
C μModule
®
Isolator
featuring the LTM2892-I. The demo circuit operates from
external supply voltages on V
CC1
, V
L1
, V
CC2
, and V
L2
. It
communicates all necessary signaling across the isolation
barrier through LTC’s Isolator™ μModule Technology.
L
, LT, LTC, LTM, Linear Technology, the Linear logo and μModule are registered trademarks
and Isolator is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
PERFORMANCE SUMMARY
OPERATING PRINCIPLES
Design files for this circuit board are available at
http://www.linear.com/demo
Specifications are at T
A
= 25°C
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
CC1
, V
CC2
Input Supply Range
3.0
5.5
V
V
L1
, V
L2
Logic Supply Range
3.0
5.5
V
f
MAX
Maximum Data Rate
INx
→
OUTx, C
L
= 15pF
20
MHz
I
2
C Communication
400
kHz
V
IORM
Maximum Working Insulation Voltage
GND1 to GND2
850
V
DC
600
V
RMS
Common Mode Transient Immunity
50
kV/μs
The LTM2892-I requires two to four external power sup-
plies for operation, one for power and one for the signal
interface, on each side of the isolation barrier. The logic
supplies may be tied to the input supplies. Isolation is
maintained by the separation of GND1 and GND2 where
significant operating voltages and transients can exist
without affecting the operation of the LTM2892-I. The ON1
and/or ON2 pins enable or shut down the LTM2892-I, both
must be driven to their respective logic supply voltage for
proper operation. All I
2
C or digital signals are referenced
to the logic supply pins V
L1
or V
L2
.
I
2
C signaling does not require any additional components.
The demo board includes pull-up resistors on SDA1 and
SCLIN. SCLOUT and SDA2 do not require external pull-ups,
SCLOUT is a push-pull output and SDA2 is pulled high
through an integral current source within the LTM2892-I.
Do not use external pull-up resistors or current sources
on SCLOUT or SDA2.
I
2
C signaling is configured by defining the LTM2892-I
pins as follows:
Logic
Side:
SCLIN = SCL(IN), and SDA1 = SDA(IN).
Isolated
Side:
SCLOUT = SCL(OUT), SDA2 = SDA(OUT).
Reference Figure 1 for schematic representation.
No special precautions are required for low RF emissions.
EMI performance is shown in Figure 2, measured using
a gigahertz transverse electromagnetic (GTEM) cell and
method detailed in IEC 61000-4-20, Testing and Measure-
ment Techniques – Emission and Immunity Testing in
Transverse Electromagnetic Waveguides.
