78M6612 Data Sheet
DS_6612_001
7 Pin Descriptions
7.1 Power/Ground Pins
Name
Type Circuit Description
Analog ground: This pin should be connected directly to the ground
plane.
GNDA
P
P
P
P
–
–
–
–
Digital ground: This pin should be connected directly to the ground
plane.
GNDD
Analog power supply: A 3.3V power supply should be connected to
this pin, must be the same voltage as V3P3SYS.
V3P3A
System 3.3 V supply. This pin should be connected to a 3.3 V power
supply.
V3P3SYS
Auxiliary voltage output of the chip, controlled by the internal 3.3 V
selection switch. In mission mode, this pin is internally connected to
V3P3SYS. In BROWNOUT mode, it is internally connected to
VBAT. This pin is floating in LCD and sleep mode.
V3P3D
O
13
Battery backup power supply. A battery or super-capacitor is to be
connected between VBAT and GNDD. If no battery is used, connect
VBAT to V3P3SYS.
VBAT
V2P5
P
12
10
Output of the internal 2.5 V regulator. A 0.1 µF capacitor to GNDA
should be connected to this pin.
O
7.2 Analog Pins
Name
Type Circuit Description
Line Current Sense Inputs: These pins are voltage inputs to the
IA, IB
I
I
6
internal A/D converter. Typically, they are connected to the outputs of
current sensors. Unused pins must be connected to V3P3A.
Line Voltage Sense Inputs: These pins are voltage inputs to the
internal A/D converter. Typically, they are connected to the outputs of
resistor dividers. Unused pins must be connected to V3P3A or
tied to the voltage sense input that is in use.
VA, VB
V1
6
Comparator Input: This pin is a voltage input to the internal power-fail
comparator. The input voltage is compared to the internal BIAS
voltage (1.6 V). If the input voltage is above VBIAS, the comparator
output will be high (1). If the comparator output is lower, a voltage
fault will occur and the chip will be forced to battery mode.
I
7
Voltage Reference for the ADC. This pin is normally disabled by
setting the VREF_CAL bit in the I/O RAM and can then be left
unconnected. If enabled, a 0.1 µF capacitor to GNDA should be
connected.
VREF
O
I
9
8
Crystal Inputs: A 32 kHz crystal should be connected across these
pins. Typically, a 27 pF capacitor is also connected from each pin to
GNDA. It is important to minimize the capacitance between these
pins. See the crystal manufacturer datasheet for details.
XIN
XOUT
Pin types: P = Power, O = Output, I = Input, I/O = Input/Output
The circuit number denotes the equivalent circuit, as specified under “I/O Equivalent Circuits”.
106
Rev. 1.2
TERIDIAN [ TERIDIAN SEMICONDUCTOR CORPORATION ]
