Datasheet

Analog Integrated Circuit Device Data
77 Freescale Semiconductor
MC34708
Functional Block Description
7.6 Battery Management
BATTERY CHARGER NO LONGER SUPPORTED ON
MC34708.
7.7 Analog to Digital Converter
The ADC core is a 10-bit converter. The ADC core and logic run at an internally generated frequency of approximately 1.33 MHz.
The ADC is supplied from VCORE. The ADC core has an integrated auto calibration circuit which reduces the offset and gain
errors.
7.7.1 Input Selector
The ADC has 16 input channels. Table 67 gives an overview of the characteristics of each of these channels.
Some of the internal signals are first scaled to adapt the signal range to the input range of the ADC. The battery current is
indirectly read out by the voltage drop over the resistor in the charge path and battery path respectively. For details on scaling,
see
Dedicated Readings.
Table 67. ADC Inputs
Channel Signal read Input Level Scaling Scaled Version
0
Battery Voltage (BATTISNSN)
0 – 4.8 V /2 0 – 2.4 V
1
Battery Current (BATTISNSN-BATTISNSP)
-80 mV – +80 mV
(61)
x15 -1.2 to +1.2 V
2
Application Supply (BPSNS)
0 to 4.8 V /2 0 – 2.4 V
3
Die temperature
-40 – 150 °C x1 1.2 – 2.4 V
4
Reserved
Reserved Reserved Reserved
5
USB Voltage (VBUS)
0 – 6.0 V x0.4 0 – 2.4 V
6
Reserved
Reserved Reserved Reserved
7
Reserved
Reserved Reserved Reserved
8
Coincell Voltage
0 – 3.6 V x2/3 0 – 2.4 V
9
ADIN9
(62)
0 – 2.4 V x1 0 – 2.4 V
10
ADIN10
(62)
0 – 2.4 V x1 0 – 2.4 V
11
ADIN11
(62)
0 – 2.4 V x1 0 – 2.4 V
12
ADIN12/TSX1
(63)
0 – 2.4 V x1/x2 0 – 2.4 V
13
ADIN13/TSX2
(63)
0 – 2.4 V x1/x2 0 – 2.4 V
14
ADIN14/TSY1
(63)
0 – 2.4 V x1/x2 0 – 2.4 V
15
ADIN15/TSY2
(63)
0 – 2.4 V x1/x2 0 – 2.4 V
Notes
61. Equivalent to -4.0 A to +4.0 A of current with a 20 mOhm sense resistor.
62. Input must not exceed the BP voltage.
63. Input must not exceed BP or VCORE.