5
dc1605bf
DEMO MANUAL DC1605B
theory of operation
may notice some lag in the update rate of the displayed
voltages.
SELECTING A DEVICE ADDRESS
The DC1605B has jumpers (JP7, JP8) labeled ASEL0 and
ASEL1 which allow the user to select one of nine I
2
C ad-
dresses. See Table 3.
Table 3. Address Selection of LTC2936
I
2
C ADDRESS (7-BIT)
ASEL1
POSITION
ASEL0
POSITION
DEFAULT
0x50
L
L
•
0x51
L
Z
0x52
L
H
0x53
Z
L
0x54
Z
Z
0x55
Z
H
0x58
H
L
0x59
H
Z
0x5A
H
H
Regardless of the jumper setting, the part will always
respond to the I
2
C global 7-bit addresses 0x0C and 0x73.
STATUS_WORD REGISTER
The STATUS_WORD register is a read-only register that
provides a summary of fault status on all six HI and LO
comparator outputs, and are determined by the comparator
threshold/configuration settings and V
n
voltages. Faults
may be disabled by setting GPI pins to MARG or UVDIS.
RESTORING RAM AND GUI FROM LTC2936
To restore the operating memory (RAM) from the LTC2936
EEPROM contents, click the “R” NVM-to-RAM icon in the
toolbar. To read the RAM registers into the GUI, click the
“R” RAM-to-PC icon in the toolbar.
DC1605B LEDs
The DC1605B board has two green LEDs. When USB power
(DC1613 Controller) or external power (6V to 14V jack) is
applied, the +5V green LED will illuminate. The +5V supply
provides power to the support circuitry, not necessarily to
the LTC2936. Jumper JP9 determines how the LTC2936
The multichannel DAC emulates a 6-channel programmable
power supply that is used to place “rail” voltages at levels
that replicate the user’s system rails. This avoids the need
for the user to wire actual supply rails to the demo board,
however the board was designed to allow this use case.
The DAC output range is 0V to 4V. This is sufficient for
demo purposes. Simply place the V1-V6 jumpers to “INT”
for internal DAC use, and ensure the LTC2936 is powered
by setting JP9 appropriately.
POWERING THE BOARD
The DC1605B board can be powered from the DC1613
USB’s 5V power or from a wall-powered 12V supply
(jack). The LTC2936 hex supervisor can be powered in a
number of different ways. The chip itself is powered from
the on-board 5V supply or an external supply. There is a
table silk-screened onto the board as a reminder. If the
USB power or jack power is present, the +5V LED will
illuminate. The LTC2936 can then be powered by setting
the jumper to “INT .” Alternatively set the jumper to “EXT”
to connect an external power supply voltage to the V
PWR
turret. With JP9 set to “EXT,” apply an external 3.3V sup-
ply. If the jumper is removed, apply an external voltage in
the range 3.4V to 13.9V. The board comes pre-configured
with jumpers JP1-JP6 set to the INTERNAL position which
allows the on-board 5V LDO regulator to power all circuits.
NOTE: Turrets V1-V6 are tied directly to the LTC2936
independent of the jumper settings.
The DC1605B uses a multiplexed ADC that is used to
provide voltage readback values. The telemetry plot in
the GUI is similar to a multichannel oscilloscope which is
capable of displaying any parameter that is displayed in
the telemetry window. Due to the nature of a multiplexed
ADC converter, it has an associated ADC loop time. The
total ADC loop time is ~400ms for a given channel. You
