ASI4UC-G1-SR-7 ZMDI, ASI4UC-G1-SR-7 Datasheet - Page 15

• Manufacturer Part Number: ASI4UC-G1-SR-7
• Description: Interface - Specialized ASI
• Manufacturer: ZMDI

Specifications of ASI4UC-G1-SR-7

• Product Category: Interface - Specialized
• Rohs: yes
• Product Type: Actuator Sensor Interface IC
• Operating Supply Voltage: 16 V to 33.1 V
• Supply Current: 6 mA
• Maximum Power Dissipation: 850 mW
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: SSOP-28
• Minimum Operating Temperature: - 25 C

Data Sheet
January 30, 2012
DIGITAL LOGIC The digital logic block contains UART, Main State Machine, E²PROM memory and other
ELECTRONIC
INDUCTOR
POWER
SUPPLY
OSCILLATOR
THERMAL
OVERLOAD
PROTECTION
ASI4U / ASI4U-E
Spec. 3.0 Com
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 2.1
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without
the prior written consent of the copyright owner. The information furnished in this publication is PRELIMINARY and subject to
changes without notice.
/
pliant Universal AS-I IC
control logic. E²PROM write access and other I/O operations of the Main State Machine
are supported in Slave Mode only (see description of general IC operational modes
below). In Master Mode the IC is basically equivalent to a physical layer transceiver.
If Slave Mode is activated, the UART demodulates the received telegrams, verifies
telegram syntax and timing and controls a register interface to the Main State Machine.
After reception of a correct telegram, the UART generates appropriate Receive Strobe
signals that tell the Main State Machine to start further processing. The Main State
Machine decodes the telegram information and starts respective I/O processes or
E²PROM access. A second register interface is used to send data back to the UART for
construction of a telegram response. The UART modulates the response data into a
Manchester-II-coded bit stream that is used to control the TRANSMIT unit.
The electronic inductor is basically a gyrator circuit. It provides an inductive behavior
between the IC pins UIN and UOUT while the inductance is controlled by the capacitor on
pin CAP. The inductor shall decouple the power regulator of the IC as well as the external
load circuit from the AS-i bus and hence prevent cross talk or switching noise from
disturbing the telegram communication on the bus.
The AS-i Complete Specification describes the input impedance behavior of a slave
module by an equivalent circuit that consists of R, L and C in parallel. For example, a
slave module in Extended Address Mode shall have R > 13.5 kOhm, L > 13.5 mH and C <
50pF. The electronic inductor of the ASI4U delivers values that are well within the required
ranges for output currents up to 55mA. More detailed parameters can be found in chapter
3.17.2.
The electronic inductor requires an external capacitor of 10µF at pin UOUT for stability.
The power supply block consists of a bandgap referenced 5V-regulator as well as other
reverence voltage and bias current generators for internal use. The 5V regulator requires
an external capacitor at pin U5R of at least 1µF for stability. It can source up to 4mA for
external use, however the power dissipation and the resulting device heating become a
major concern, if too much current is drawn from the regulator.
The oscillator supports direct connection of 8.000 MHz or 16.000 MHz crystals with a
dedicated load capacity of 12pF and parasitic pin capacities of up to 8pF. The IC
automatically detects the oscillation frequency of the connected crystal and controls the
internal clock generator circuit accordingly.
After power-on reset the IC is set to 16.000 MHz operation by default. After about 200µs it
will either switch to 8.000 MHz operation or remain in the 16.000 MHz mode. The
frequency detection is active until the first AS-i telegram was successfully received in
order to make sure the IC found the correct clock frequency setting. The detection result is
locked thereafter to increase resistance against burst or other interferences.
The oscillator unit also contains a clock watch dog circuit that can generate an
unconditioned IC reset if there was no clock oscillation for more than about 20µs. This is
to prevent the IC from unpredicted behavior if no clock signal is available anymore.
The IC is self protected against thermal overheating and short circuiting of pin UOUT
towards IC ground.
If the silicon die temperature rises above around 140°C for more than 2 seconds, the IC
detects thermal overheating, switches off the electronic inductor, performs an IC reset and
sets all analog blocks to power down mode. The 5V-regulator is of course also turned off
in this state, however, there will still remain a voltage of about 3 … 3.5V available at U5R
that is derived from the internal start circuitry. The overheat protection state can only be
left by power-cycling the AS-i voltage.
Shortcutting pin UOUT towards IC ground leads to the same IC behavior as thermal
overheating.
15 of 63