Datasheet

Analog Integrated Circuit Device Data
Freescale Semiconductor 80
MC34708
Functional Block Description
Figure 19. Input Configuration with Battery Current Sense
7.7.3.3 Channel 2 Application Supply
The application supply voltage is read at the BPSNS pin on channel 2. The battery voltage is first scaled as V
BPSNS
/2 to fit the
input range of the ADC.
7.7.3.4 Channel 3 Die Temperature
The relation between the read out code and temperature is given in Table 73.
The Actual Die Temperature is obtained as follows: Die Temp = 25 + 0.426 * (ADC Code - 680)
7.7.3.5 Channel 4 Reserved
Channel 4 is reserved.
7.7.3.6 Channel 5 VBUS Voltage
The VBUS voltage is measured at the VBUS pin on channel 5. The VBUS voltage is first scaled in order to fit the input range of
the ADC by multiplying by 0.4.
7.7.3.7 Channel 6 and 7 Reserved
Channel 6 is reserved.
Table 72. Application Supply Voltage Reading Coding
Conversion Code
ADRESULTx[9:0]
Voltage at Input ADC in V Voltage at BPSNS in V
1 111 111 111 2.400 4.800
1 000 010 101 1.250 2.500
0 000 000 000 0.000 0.000
Table 73. Die Temperature Voltage Reading
Parameter Min Typ Max Unit
Die Temperature Read Out Code at 25 °C - 680 - Decimal
Slope temperature change per LSB - +0.426 - °C/LSB
Slope error - - 5.0 %
CHRGFB BATTISNSN BATTISNSP
BP
GBAT BPSNS BATT
BP
R1
20m
10u
10u
C1
C2
Input/Battery
Monitoring
Battery