SA58640 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved.
Product data sheet Rev. 3 — 12 April 2011 12 of 20
NXP Semiconductors
SA58640
Low-voltage mixer FM IF system
14. Test information
(1) Set your RF generator at 45.000 MHz, use a 1 kHz modulation frequency and a 6 kHz deviation if
you use 16 kHz filters, or 8 kHz if you use 30 kHz filters.
(2) The measured typical sensitivity for 12 dB SINAD should be 0.45 μV or −114 dBm at the RF input.
(3) The smallest RSSI voltage (i.e., when no RF input is present and the input is terminated) is a
measure of the quality of the layout and design. If the lowest RSSI voltage is 500 mV or higher, it
means the receiver is in regenerative mode. In that case, the receiver sensitivity will be worse than
expected.
(4) The C-message and de-emphasis filter combination has a peak gain of 10 dB for accurate
measurements. Without the gain, the measurements may be affected by the noise of the scope
and HP339A analyzer. The de-emphasis filter has a fixed −6 dB/octave slope between 300 Hz and
3kHz.
Fig 11. Application circuit test setup
SCOPE
SA58640
DEMOBOARD
(3)
RSSI AUDIO
002aab12
RF GENERATOR
45 MHz
(1)
V
CC
(+3 V)
DC VOLTMETER
HP339A DISTORTION
ANALYZER
(2)
C-MESSAGE
(4)
DE-EMPHASIS
FILTER
