Linear Technology DC1789A Demo Manual

Description
Demonstration circuit 1789A is an isolated USB transceiver
with isolated power featuring the
circuit features an EMI optimized circuit configuration and
printed circuit board layout. All components are integrated
into the µModule
from a supply on V
an isolated output voltage on V
performance summary
SYMBOL PARAMETER
V Operating Supply Range (Isolated Power Input)
CC
V Operating Supply Range (USB Bus Power Input)
BUS
V Regulated Output Voltage
CC2
t Low Speed Data Rate
LDR
t Full Speed Data Rate
FDR
V Maximum Working Insulation Voltage
IORM
Common Mode Transient Immunity
operating principles
The LTM2884 contains an isolated DC/DC converter de-
livering power to V
and/or V . Isolation is maintained by the separation of
BUS
GND and GND2 where significant operating voltages and
transients can exist without affecting the operation of the
LTM2884. The logic side ON pin enables or shuts down
the LTM2884. All logic side signals are referenced to the
logic supply pin V
inputs, V and V
CC
than 200mA from V
external supply of 8.1V to 16.5V. V
Arrow.com.
Downloaded from
LTM 2884. The demo
®
isolator. The demo circuit operates
®
and/or V . The part generates
CC BUS
and communicates all
CC2
at 5V from the input supply V
CC2
. The LTM2884 has two power supply
LO
. For applications requiring more
BUS
, V must be connected to an
CC2 CC
may be connected
BUS
DEMO MANUAL DC1789A
Isolated USB Transceiver
necessary signaling across the isolation barrier through
LTC's isolator µModule technology.
Design files for this circuit board are available at
http://www.linear.com/demo
L, LT, LTC, LTM, Linear Technology, the Linear logo and µModule are registered trademarks of
Linear Technology Corporation. All other trademarks are the property of their respective owners.
(T = 25°C)
A
CONDITIONS
V = V = 4.4V, I = 200mA
CC BUS CC2
V = 8.1V, I = 500mA
CC CC2
GND to GND2
to USB bus power or to the external supply. For applica-
tions requiring 200mA or less connect V
CC
USB bus power.
Upstream USB signaling is controlled by the bidirectional
+
pins D1 and D1
configured dependent upon the connected downstream
peripheral device. For full speed and low speed devices
the pull-up is asserted on D1
downstream USB data pins, D2
integrated 15k pull-down resistors.
LTM2884
with Isolated Power
MIN TYP
4.4 12
4.4 5
4.75 5
4.75 5
1.5
12
560
400
30
–
. A 1.5k pull-up resistor is automatically
+ –
and D1 , respectively. The
+
and D2
MAX UNITS
16.5 V
16.5 V
5.25 V
5.25 V
Mbps
Mbps
V
DC
V
RMS
kV/µs
and V to
CC BUS
–
, each have
dc1789afa
1