CS5490
2. PIN DESCRIPTION
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
XOUT
XIN
RESET
IIN-
VDDD
MODE
RX
TX
DO
VDDA
GNDA
VREF+
IIN+
VIN+
VIN-
VREF-
Clock Generator
Crystal In
2,1
XIN, XOUT — Connect to an external quartz crystal. Alternatively, an external clock can be
supplied to the XIN pin to provide the system clock for the device.
Crystal Out
Control Pins and Serial Data I/O
Digital Output
12
DO — Configurable digital output for energy pulses, interrupt, energy direction, and
zero-crossings.
Reset
3
RESET — An active-low Schmitt-trigger input used to reset the chip.
TX, RX — UART serial data output/input.
Serial Interface
13,14
15
Operating Mode Select
Analog Inputs/Outputs
Voltage Input
MODE — Connect to VDDA for proper operation.
6,7
5,4
9,8
VIN+, VIN- — Differential analog input for the voltage channel.
IIN+, IIN- — Differential analog input for the current channel.
VREF+, VREF- — The voltage reference output and return.
Current Input
Voltage Reference Input
Power Supply Connections
Internal Digital Supply
Positive Analog Supply
Analog Ground
16
11
10
VDDD — Decoupling pin for the internal digital supply.
VDDA — The positive analog supply.
GNDA — Analog ground.
2.1.2 Current Input
2.1 Analog Pins
The output of the current-sensing shunt resistor or
transformer is connected to the IIN input pins of the
CS5490. To accommodate different current-sensing
The CS5490 has two differential inputs, one for voltage
(VIN) and one for currentIIN). The CS5490 also has
two voltage reference pins (VREF) between which a
0.1µ bypass capacitor must be placed.
elements, the current channel incorporates
a
programmable gain amplifier (PGA) with two selectable
input gains, as described in the Config0 register
description 6.6.1 Configuration 0 (Config0) – Page 0,
Address 0 on page 31. There is a 10x gain setting and
a 50x gain setting. The full-scale signal level for the
current channel is ±50mV and ±250mV for 50x and 10x
gain settings, respectively. If the input signal is a sine
2.1.1 Voltage Input
The output of the line voltage resistive divider or
transformer is connected to the VIN input of the
CS5490. The voltage channel is equipped with a 10x,
fixed-gain amplifier. The full-scale signal level that can
be applied to the voltage channel is ±250 mV. If the
input signal is a sine wave, the maximum RMS
wave, the maximum RMS voltage is 35.35 mV
or
RMS
176.78mV
, which is approximately 70.7% of
RMS
voltage is 250mVp / 2 176.78mV
approximately 70.7% of maximum peak voltage.
,
which is
RMS
maximum peak voltage.
6
DS982F2
APEX [ CIRRUS LOGIC ]
