ADM3055EBRIZ datasheet(22/24 Pages) AD

22 / 24 page

ADM3055E/ADM3057E

Data Sheet

Rev. A | Page 22 of 24

APPLICATIONS INFORMATION

PCB LAYOUT

Power supply bypassing is required at the logic input supply,

VIO, and at the shared CAN transceiver and digital isolator

input supply pin, VISOIN. Low equivalent series resistance (ESR)

bypass capacitors are required and must be placed as close to

the chip pads as possible. The ADM3055E and the ADM3057E

signal and power isolated CAN transceivers do not require

external interface circuitry for the logic interfaces.

The integrated dc-to-dc converter supply input pin, VCC, requires

parallel 10 µF and 0.1 µF bypass capacitors placed close to the

pin. Noise suppression requires a low inductance, high frequency

capacitor. Ripple suppression and proper regulation require a

large value capacitor. Effective bypass capacitance is also

required on the isolated output supply pin, VISOOUT, for proper

operation of the integrated dc-to-dc converter. Note that the

total trace length between the ends of the low ESR capacitors

and the input power supply pins, VCC, VIO, VISOIN, and VISOOUT,

must not exceed 2 mm.

RADIATED EMISSIONS AND PCB LAYOUT

The ADM3055E and the ADM3057E signal and power isolated

CAN FD transceivers pass EN 55022 Class B by 6 dB on a 2-layer

PCB design with ferrite beads. Neither PCB stitching capacitance

nor high voltage surface-mounted technology (SMT) safety

capacitors are required to meet this emissions level.

The ADM3055E and the ADM3057E have an internal split pad

lead frame on the bus side to isolate noise generated by the dc-

to-dc converter from the transceiver. For best noise suppression,

filter both the VISOOUT power supply pin and GNDISO power

supply return pin for high frequency currents before routing

power to the transceiver. Use surface-mount ferrite beads in

series with the signals, as shown in Figure 33.

The isoPower integrated dc-to-dc converters of the ADM3055E

and the ADM3057E produce a 180 MHz carrier frequency to

transmit power through the chip scale transformer. The

impedance of the ferrite bead must be approximately 2 kΩ

between the 100 MHz and 1 GHz frequency range to reduce the

emissions of the 180 MHz primary switching frequency and

360 MHz secondary side rectifying frequency. See Table 14 for

examples of appropriate surface-mount ferrite beads. Although

the ferrite beads are beneficial for emissions performance, the

ferrite beads are not required for functionality.

Table 14. Surface-Mount Ferrite Beads Example

Manufacturer

Part No.

Taiyo Yuden

BKH1005LM182-T

Murata Electronics

BLM15HD182SN1

ADM3055E/

ADM3057E

GND1

AUXIN

STBY

10µF

0.1µF

0.22µF

0.1µF

0.01µF

RSLOPE

FERRITES

TXD

SILENT

RXD

VIO

VCC

GND1

GNDISO

GND2

CANL

CANH

GND2

VISOIN

AUXOUT

GNDISO

VISOOUT

0.1µF 0.01µF

Figure 33. Recommended PCB Layout

THERMAL ANALYSIS

The ADM3055E and the ADM3057E consist of six internal die

attached to a split lead frame with four die attach pads. For the

purposes of thermal analysis, the die are treated as a thermal

unit, with the highest junction temperature reflected in the θJA

value in Table 10. The θJA value is based on measurements taken

with the devices mounted on a JEDEC standard, 4-layer board

with fine width traces and still air. Under normal operating

conditions, the ADM3055E and the ADM3057E can operate at

full load across the full temperature range without derating the

output current.

INSULATION LIFETIME

All insulation structures eventually break down when subjected

to voltage stress over a sufficiently long period of time. The rate

of insulation degradation is dependent on the characteristics of

the voltage waveform applied across the insulation as well as on

the materials and material interfaces.

The two types of insulation degradation of primary interest are

breakdown along surfaces exposed to the air and insulation

wear out. Surface breakdown is the phenomenon of surface

tracking and is the primary determinant of surface creepage

requirements in system level standards. Insulation wear out

is the phenomenon where charge injection or displacement

currents inside the insulation material cause long-term

insulation degradation.

ADM3055EBRIZ датащи(PDF) 22 Page - Analog Devices

ADM3055EBRIZ датащи(HTML) 22 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

датащи скачать

ссылки URL