Datasheet

6.2 Digital Control Signal PIN Configuration, SW1
7 Clock Source
5VCC
EN
W2
ConnectWhen
UsingOnboard
20MHzClock
W3
Internalor
External
ModularClock
Select
INT
EXT
MCLK
www.ti.com Clock Source
When using the I
2
C function through U5 (with or without ADCPro connected), all SW1 switches should be
in the OFF position (see Figure 4 ).
The data clock and data out communications are directed through P2. All remaining ADS1672 digital
control pins are configured with SW1. Table 4 describes the settings of the digital configuration switches.
The shunt on W3 must be moved to cover pin positions 2 and 3 in order to use the external clock applied
to J3. The control signal operating modes in Table 4 are further explained in the ADS1672 data sheet.
Note: All SW1 switches must be configured in the OFF position when using ADCPro software.
Table 4. SW1: Supplemental Analog Interface Pinout
Pin Number Signal Description
Data rate selection, bit 1 (oversampling
SW1.1 DRATE2
ratio select pin)
Data rate selection, bit 0 (oversampling
SW1.2 DRATE1
ratio select pin)
SW1.3 NC No connection
Digital filter path selection: If FPATH = '0',
SW1.4 FPATH then path is wide-bandwidth; if FPATH =
'1', then path is low-latency
Configure low-latency digital filter: If
LL_CONFIG = '0', then single-cycle settling
SW1.5 LL_CONFIG
is selected; if LL_CONFIG = '1', the
fast-response is selected
This pin should always be in its off position
SW1.6 LVDS or '0'. The LVDS interface is not supported
on this EVM.
Shift-clock source select: If SCLK_SEL =
'0', then SCLK is internally generated; if
SW1.7 SCLK_SEL
SCLK_SEL - '1', then SCLK must be
externally generated
SW1.8 PDWN Power-down control; active low
SW1.9 NC No connection
SW1.10 NC No connection
You can either select the onboard 20MHz crystal oscillator as the master clock for the ADS1672, or apply
an external clock signal through J3. When the onboard 20MHz clock is used, the W2 jumper must be
installed (Figure 5 ). W2 is an enable function for the onboard crystal oscillator (X1). W3 in positions 1-2
sends the onboard clock to the DUT by way of the buffer, U8. When using an external clock, move the W3
jumper (see Figure 4 and Figure 5 ) on pins 1-2 to cover pins 2-3, and remove the W2 jumper (see
Figure 6 ) to disable X1. Then apply your clock source to J3. Otherwise, simply remove the jumper when
an external clock is inserted at J3.
Figure 5. W2 and W3 Jumpers for Onboard Clock
SBAU147 – March 2009 ADS1672EVM and ADS1672EVM-PDK User's Guide 9
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