Datasheet

LTC2389-16
30
238916f
DIGITAL INTERFACE
To accommodate a variety of application-specific proces-
sor and FPGA data bus widths, the LTC2389-16 output
bus may be configured to operate in either 16-bit parallel,
8-bit parallel or serial modes, as described in Table 1. The
flexible OV
DD
supply allows the LTC2389-16 to commu-
nicate with any digital logic operating between 1.8V and
5V, including 2.5V and 3.3V systems.
16-Bit Parallel Bus Configuration
In applications such as FPGA and CPLD based solutions
or 16-bit microcontroller based solutions where a full
16-bit wide parallel data bus is available, the LTC2389-16
is capable of providing each conversion result R[15:0]
as one 16-bit word on pins D[15:0]. To select this bus
configuration, pin MODE0 should be driven to MODE0
= 0 and pin A1 should be driven to A1 = 0, as described
in Table 1. If the application does not require the bus to
be shared, drive the chip select pin CS = 0 to enable the
LTC2389-16 to drive the bus continuously, as shown in
Figure 14. In applications where the bus must be shared,
drive CS = 1 when other devices are using the bus to Hi-Z
the LTC2389-16 bus pins and drive CS = 0 to allow the
LTC2389-16 to drive
the bus, as shown
in Figures 15 and 16.
8-Bit Parallel Bus Configuration
In applications such as 8-bit microcontroller based solu-
tions where an 8-bit wide parallel data bus is available, the
LTC2389-16 is capable of providing each conversion result
R[15:0] in two 8-bit words on pins D[15:8]. To select this
bus configuration, pin MODE0 should be driven to MODE0
= 0, as described in Table 1. In this configuration, address
input pin A1 controls whether the upper byte R[15:8] or
the lower byte R[7:0] of the conversion result is driven
on D[15:8], as shown in Figure 17. Note that, as shown in
Table 1, D[7:0] also functions as an 8-bit wide parallel bus
with A1 providing control of the opposite polarity as it does
on D[15:8]. Use of D[7:0] as an 8-bit parallel bus should
be avoided in applications where it is important to maintain
compatibility with 18-bit versions of the LTC2389 family,
as described in the Pin Compatibility with LTC2389-18
section. The chip select pin, CS, enables the 8-bit paral-
lel bus to be shared between multiple devices. See the
16-Bit Parallel Bus Configuration section for further details.
applications inFormation