User Guide

PAMS
Technical Documentation
NSE–8/9
System Module
Page 2– 52
Issue 1 07/99
Battery Voltage
The ADC is to be calibrated in production / service, with a one point
calibration at 2.7V.
Table 25. Battery voltage, ADC properties
Parameter min typ max Unit Comment
Resolution 10 bits 1024 ADC output values
Conversion error 8.6 9.4 10.2 mV corresponding to +/– 2 LSB
Vb range 0 3.6 V range given by PSCC
Vb voltage @ ADC satura-
tion
4.4 4.8 5.2 V ADC reading 1023
Vb ADC resolution 4.3 4.7 5.1 mV/bit
Vrssi_adc input range 0.1 Vref V Vref =1.5V +/– 2%
min limit due to CCONT
Un–calibrated ADC read-
ing @2.7V
525 575 625
The capacitor C154, is applied to attenuate the noise originated from the
different ground reference points and general TDMA and other noise.
Battery Temperature
The battery temperature is measured with a NTC (R0=47k ± 10 % with
B = 4050 ±3 %), R127, placed on the transceiver PCB close to the battery
ground terminal,X101, which acts as a thermal conductor. The BTEMP
line has a 100k pull–up,R125, to VREF.
The MCU can calculate the battery temperature by reading the BTEMP
line DC–voltage level with the CCONT BTEMP A/D–converter.
Table 26. Temperature conversion constants
Value Reference Nominal
value
Tolerances
Vref [volt] N100 1.5  1.5 %
R0 [Kohm] R127 47  10%
Tref [Kelvin] 298 0
B [Kelvin] 4050  3 %
Rpu [Kohm] R125 47  5.0 %
Table 27. ADC reading and NTC resistance vs. temperature
T [C] ADC
read
R [k] T [C] ADC
read
R [k] T [C] ADC
read
R [k]
–40 976 2074 5 568 124.8 50 144 16.4
–35 957 1440 10 502 96.5 55 122 13.6
–30 931 1015 15 439 75.3 60 104 11.3