LTC2946
8
2946fa
For more information www.linear.com/LTC2946
PIN FUNCTIONS
ADIN: ADC Input. The onboard ADC measures voltages
between 0V and 2.048V with respect to GND or INTV
CC
.
Tie to ground if unused. See Table 3 in the Applications
Information section for details.
ADR1, ADR0: I
2
C Device Address Inputs. Connecting these
pins to INTV
CC
, GND, or leaving the pins open configures
one of nine possible addresses. See Table 1 in the Ap-
plications Information section for details.
CLKIN
:
Clock Input. Connect to ground to use the internal
±5% clock. For improved accuracy, connect to an external
crystal oscillator circuit or drive with an external clock.
CLKOUT: Clock Output. Connect to an external crystal
oscillator circuit. Leave open if unused.
EXPOSED PAD: Exposed Pad may be left open or con
-
nected to device ground. For best thermal performance,
connect to a large PCB area.
GND:
Device Ground.
GPIO1: General Purpose Input/Output (Open Drain). Con
-
figurable to general purpose output or input. Ti
e to ground
if unused. See Table 9 in the Applications Information
section for details.
GPIO2: General Purpose Input/Output (Open Drain). Con
-
figurable to general purpose output, input or accumulation
enable
(ACC) to gate internal accumulators. Tie to ground
if unused. See Table 9
in the Applications Information
section for details.
GPIO3:
General Purpose Input/Output (Open Drain).
Configurable to general purpose output, input or ALERT.
As ALERT, it is pulled to ground when a fault occurs to
alert the host controller. A fault alert is enabled by setting
the corresponding bit in the ALERT registers, as shown
in Tables 5 and 8. Tie to ground if unused. See Table 9 in
the Applications Information section for details.
INTV
CC
: Internal Low Voltage Supply Input/Output. This pin
is used to power internal circuitry. It can be configured as
a direct input for a low voltage supply, as a linear regula
-
tor from a higher voltage supply connected to V
DD
, or as
a shunt regulator. Connect this pin directly to a 2.7V to
5.8V supply if available. When INTV
CC
is powered from
an external supply, short the V
DD
pin to INTV
CC
. If V
DD
is
connected to a 4V to 100V supply, INTV
CC
becomes the
5V output of an internal series regulator that can supply
up to 10mA to external circuitry. For even higher supply
voltages, or if a floating topology is desired, INTV
CC
can
be used as a 6.3V shunt regulator. Connect the supply to
INT
V
CC
through a resistor or current source that limits the
shunt regulator current to less than 35mA. An undervolt-
age lockout
circuit disables the ADC when the voltage at
this
pin drops below 2.5V. Connect a bypass capacitor of
0.1μF or greater from this pin to ground. If an external
load is present, for loop stability use a bypass capacitor
of 0.22μF or greater.
SCL: I
2
C Bus Clock Input. Data at the SDAI pin is shifted
in or out on rising edges of SCL. This pin is driven by an
open-collector output from a master controller. An external
pull-up resistor or current source is required and can be
placed between SCL and V
DD
or INTV
CC
. The voltage at
SCL is internally clamped to 6.4V typically.
