19699-002-XTP ON Semiconductor, 19699-002-XTP Datasheet - Page 20

• Manufacturer Part Number: 19699-002-XTP
• Manufacturer: ON Semiconductor

Specifications of 19699-002-XTP

• Number Of Transmitters: 1
• Power Supply Requirement: Dual
• Package Type: LQFP
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 44
• Operating Temperature (max): 85C
• Operating Temperature (min): -40C
• Lead Free Status / RoHS Status: Compliant

AMIS-49200
noise as possible as it is used as a reference for many sub-circuits in the AMIS-49200. C8 must be a large capacitor with maximum of
100nf. C8 recommended value is 1μf.
There is one other minor difference in the recommended external circuitry between the μSAA22Q and the AMIS-49200. Figure 14
shows the start-up circuits recommended for the μSAA22Q and the AMIS-49200. The circuit shown for the AMIS-49200 is different from
that shown for the μSAA22Q but either one will work. Both are current sources that turn on when power is applied to the H1 segment
terminals so that the AMIS-49200 can turn on without any turn-on transients on the network.
5.4 Active Components
Transistors Q1 – Q4 are ordinary small signal transistors. Diodes D1 and D2 are similarly ordinary small signal diodes. Users desiring
to replace a μ SAA22Q with the AMIS-49200 in an existing design should be able to use whatever transistors and diodes were used with
the μ SAA22Q. For new designs, the specified transistors can be used or other devices may be chosen.
5.5 Alternative Designs
Some users of the Yokogawa μ SAA22Q did not use the exact recommended external circuit for the media interface circuit (see Figure
13). Using the AMIS-49200 without the Yokogawa recommended external circuit may result in some compatibility problems. There are
many alternative designs and it is beyond the scope of this document to identify all possible configurations and their associated design
implications. Please refer to the AMIS-49200 Fieldbus MAU Reference Design Application Note for a recommended, FOUNDATION
Fieldbus certifiable board design.
5.6 Verification
All designs using the AMIS-49200 should re-run the entire physical layer conformance test as defined in FOUNDATION Fieldbus
document FF-830, FOUNDATION™ Specification 31.25 kbit/s Physical Layer Conformance Test. Board layout can alter the behavior of
all circuit implementations, even designs that follow the recommended implementation.
Startup Circuit
Figure 14: Recommended Start-up Circuits
Rev. 5 | Page 20 of 22 | www.onsemi.com
μ
SAA 22Q
V Shunt
Loop +
5.1 V
100 k
D3
R5
Startup Circuit
AMIS 49200
1 k
R6
Q1
Loop +
V Shunt