DS_6618_005
78M6618 Data Sheet
4 Pin Descriptions
4.1 Power and Ground Pins
Table 26: Power and Ground Pins
Name
Type Circuit
Description
GNDA
P
–
Analog ground: This pin should be connected directly to the ground
plane.
GNDD
V3P3A
P
P
–
–
Digital ground: This pin should be connected directly to the ground plane.
Analog power supply: A 3.3 V power supply should be connected to this
pin, must be the same voltage as V3P3SYS.
V3P3SYS
V3P3D
P
–
System 3.3 V supply. This pin should be connected to a 3.3 V power
supply.
O
13
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 left unconnected in LCD and sleep mode. A bypass capacitor
to ground should not exceed 0.1 µF.
VBAT
V2P5
P
12
10
Battery backup and oscillator power supply. A battery or super-capacitor
is to be connected between VBAT and GNDD. If no battery is used,
connect VBAT to V3P3SYS.
O
Output of the internal 2.5 V regulator. Leave this pin open.
4.2 Analog Pins
Table 27: Analog Pins
Description
Name
Type Circuit
IA, IB,
IC, ID,
IE, IF,
IG, IH
I
6
Line Current Sense Inputs: These pins are voltage inputs to the internal A/D
converter. Typically, they are connected to the outputs of current sensors.
Unused pins must be tied to V3P3A.
VA, VB
V1
I
I
6
7
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 tied to V3P3A.
Comparator Input: This pin is a voltage input to the internal comparator.
The voltage applied to the pin 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 low, a voltage fault will occur. A series
5 kΩ resistor should be connected from V1 to the resistor divider.
VREF
O
I
9
8
Voltage Reference for the ADC. Normally disabled and left unconnected. If
enabled, a 0.1 µF capacitor to V3P3A should be connected to this pin.
XIN
XOUT
Crystal Inputs: A 32 kHz crystal should be connected across these pins.
Typically, a 33 pF capacitor is also connected from XIN to GNDA and a
15 pF capacitor is connected from XOUT to GNDA. It is important to mi-
nimize the capacitance between these pins. See the crystal manufacturer
datasheet for details. If an external clock is used, a 150 mV (p-p) clock
signal should be applied to XIN, and XOUT should be left unconnected.
1) Pin types: P = Power, O = Output, I = Input, I/O = Input/Output
The circuit number denotes the equivalent circuit, as specified under Section 5, I/O Equivalent Circuits.
Rev. 1.4
27
TERIDIAN [ TERIDIAN SEMICONDUCTOR CORPORATION ]
