Datasheet

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ADS8411
SLAS369B – APRIL 2002 – REVISED DECEMBER 2004
Terminal Functions
NAME NO. I/O DESCRIPTION
AGND 5, 8, 11, 12, 14, – Analog ground
15, 44, 45
BDGND 25, 35 – Digital ground for bus interface digital supply
BUSY 36 O Status output. High when a conversion is in progress.
BYTE 39 I Byte select input. Used for 8-bit bus reading. 0: No fold back 1: Low byte D[7:0] of the 16 most
significant bits is folded back to high byte of the 16 most significant pins DB[15:8].
CONVST 40 I Convert start. The falling edge of this input ends the acquisition period and starts the hold
period.
CS 42 I Chip select. The falling edge of this input starts the acquisition period.
8-Bit Bus 16-Bit Bus
Data Bus
BYTE = 0 BYTE = 1 BYTE = 0
DB15 16 O D15 (MSB) D7 D15 (MSB)
DB14 17 O D14 D6 D14
DB13 18 O D13 D5 D13
DB12 19 O D12 D4 D12
DB11 20 O D11 D3 D11
DB10 21 O D10 D2 D10
DB9 22 O D9 D1 D9
DB8 23 O D8 D0 (LSB) D8
DB7 26 O D7 All ones D7
DB6 27 O D6 All ones D6
DB5 28 O D5 All ones D5
DB4 29 O D4 All ones D4
DB3 30 O D3 All ones D3
DB2 31 O D2 All ones D2
DB1 32 O D1 All ones D1
DB0 33 O D0 (LSB) All ones D0 (LSB)
–IN 7 I Inverting input channel
+IN 6 I Non inverting input channel
NC 3 – No connection
REFIN 1 I Reference input
REFM 47, 48 I Reference ground
REFOUT 2 O Reference output. Add 1 µF capacitor between the REFOUT pin and REFM pin when internal
reference is used.
RESET 38 I Current conversion is aborted and output latches are cleared (set to zeros) when this pin is
asserted low. RESET works independantly of CS.
RD 41 I Synchronization pulse for the parallel output. When CS is low, this serves as the output enable
and puts the previous conversion result on the bus.
+VA 4, 9, 10, 13, 43, – Analog power supplies, 5-V dc
46
+VBD 24, 34, 37 – Digital power supply for bus
8