CLRC632 Datasheet, PDF (101/163 Pages) NXP Semiconductors – Multiple Protocol Contactless Reader IC

Philips Semiconductors
Product Specification Rev. 3.0; May 2003
Multiple Protocol Contactless Reader IC
CL RC632
13.3.2 FORMULA FOR THE SOURCE RESISTANCE
The relative resistance Rs_rel can be calculated by
1
Rs_rel
=
MANT_GsCfgCW
⋅ ( ) 77 EXPGsCfgCW
40
The relative resistance Rs_rel during the modulation phase can be calculated using GsCfgMod, respectively.
13.3.3 CALCULATING THE EFFECTIVE SOURCE RESISTANCE
13.3.3.1 Wiring Resistance
Wiring and bonding add a constant offset to the driver resistance, that is relevant if TX1 and TX2 are
switched to low impedance. The additional resistance for TX1 can be set approximately to
Rs_wire,TX1 ≈ 500mΩ
13.3.3.2 Effective Resistance
The source resistances of the driver transistors R_sMaxP found in the Product Information Field (see chapter
6.2) are measured at production test with GsCfgCW set to 01_hex. To get the driver resistance for a specific
value set in GsCfgMod the following formula may be used:
( ) Rs_x = Rs_{ref ,max, p} − Rs_{wire,TX 1} ⋅ Rs_rel + Rs_{wire,TX 1} .
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