Cirrus Logic CS5566 - Manual (Page 26)

CS5566
26 DS806PP2
5/4/09
4. PIN DESCRIPTIONS
CS – Chip Select, Pin 1
The Chip Select pin allows an external device to access the serial port. If SMODE = VL (SSC
Mode) and CS is held high, the SDO output and the SCLK output will be held in a
high-impedance output state.
TST – Factory Test, Pin 2
Factory test only. Connect to VLR.
SMODE – Serial Mode Select, Pin 3
The serial interface mode pin (SMODE) dictates whether the serial port behaves as a master or
slave interface. If SMODE is tied high (to VL), the port will operate in the Synchronous
Self-Clocking (SSC) mode. In SSC mode, the port acts as a master in which the converter out-
puts both the SDO and SCLK signals. If SMODE is tied low (to VLR), the port will operate in the
Synchronous External Clocking (SEC) mode. In SEC mode, the port acts as a slave in which
the external logic or microcontroller generates the SCLK used to output the conversion data
word from the SDO pin.
AIN+, AIN- – Differential Analog Input, Pin 4, 5
AIN+ and AIN- are differential inputs for the converter.
V1- – Negative Power 1, Pin 6
The V1- and V2- pins provide a negative supply voltage to the core circuitry of the chip. These
two pins should be decoupled as shown in the application block diagrams. V1- and V2- should
be supplied from the same source voltage. For single-supply operation, these two voltages are
nominally 0 V (Ground). For dual-supply operation, they are nominally -2.5 V.
V1+ – Positive Power 1, Pin 7
The V1+ and V2+ pins provide a positive supply voltage to the core circuitry of the chip. These
two pins should be decoupled as shown in the application block diagrams. V1+ and V2+ should
be supplied from the same source voltage. For single supply-operation, these two voltages are
nominally +5 V. For dual-supply operation, they are nominally +2.5 V.
BUFEN – Buffer Enable, Pin 8
Buffers on input pins AIN+ and AIN- are enabled if BUFEN is connected to V1+ and disabled if
connected to V1-.
VREF+, VREF- – Voltage Reference Input, Pin 9, 10
A differential voltage reference input on these pins functions as the voltage reference for the
converter. The voltage between these pins can range between 2.4 volts and 4.2 volts, with
4.096 volts being the nominal reference voltage value.
SLEEP 12 Sleep Mode Select
BP/UP 11 Bipolar/Unipolar Select
VREF- 10 Voltage Reference Input
VREF+ 9 Voltage Reference Input
BUFEN 8 Buffer Enable
V1+ 7 Positive Power 1
V1- 6 Negative Power 1
AIN- 5 Differential Analog Input
AIN+ 4 Differential Analog Input
3
2
CS 1 Chip Select
RST 13 Reset
VLR2 14 Logic Interface Return
CONV 15 Convert
DCR 16 Digital Core Regulator
V2+ 17 Positive Voltage 2
V2- 18 Negative Voltage 2
MCLK 19 Master Clock
VLR 20 Logic Interface Return
VL 21 Logic Interface Power
SDO 22 Serial Data Output
SCLK 23 Serial Clock Input/Output
RDY 24 Ready
TST Factory Test
SMODE Serial Mode Select