Analog Devices MAX77857 Manual page 6

Evaluates: MAX77857 (WLP)
J1 to position 1-2. This connects EN to V
header jumper J2. This connects V
supply.
MAXUSB_INTERFACE#
The MAXUSB_INTERFACE# along with the companion EV kit GUI software allows users to easily change the
MAX77857's register settings with a Windows PC. Before connecting the MAXUSB_INTERFACE# to the EV kit's
MAXUSB_INTERFACE# connector (J5), make sure the MAXUSB_INTERFACE# is configured with the following settings:
•
SW1, SW2 to ON Position (This enables I
•
Jumper (J5) to 1.8V (This sets the MAXUSB_INTERFACE#'s V
V
L
• Warning: Setting this incorrectly to 3.3V could potentially damage the MAX77857 IC.
The MAXUSB_INTERFACE# also includes an on-board LDO that can supply the necessary voltage to V
using the MAXUS_INTERFACE#, disconnect any external V
is removed from the EV kit.
2
External I C Bus
If you wish to connect to the external I
MAXUSB_INTERFACE# from the EV kit's MAXUSB_INTERFACE# connector (J5). Apply an external I/O supply to the
V pin or power the V
IO IO
logic voltage level is compatible with the MAX77857's I/O logic voltage level. Refer to the MAX77857 IC data sheet for
the appropriate I/O logic voltage level.
R Configuration Resistor
SEL
The MAX77857 includes an SEL pin to set the I
resistor with 1% tolerance (or better) should be chosen for R
0Ω. See
Table 2 for nominal R
dynamically through the I
Table 2. MAX77857 R
FEEDBACK
R
SEL
RESISTOR
(Ω)
SELECTION
0*
200
309
422
536
649
768
Internal
909
feedback
1050
resistors
1210
1400
1620
1870
2150
2490
2870
*Default value installed on the EV Kit
www.analog.com
through a 510kΩ pullup resistor so that EN is controlled by V
IN
to V so that V
IO L
2
C mode on the MAXUSB_INTERFACE#.)
2
C serial bus and not use the MAXUSB_INTERFACE#, unplug the
pin from the V pin by connecting header jumper J2. Make sure the external I
L
2
values and their corresponding settings. The switching current limit is also adjustable
SEL
2
C serial interface when the IC is enabled. See the
Selection Table
SEL
2
I C SLAVE
TYPICAL
ADDRESS
I (A)
LIM
(7-BIT)
110 0110 (0x66)
110 0111 (0x67)
7.0
110 1110 (0x6E)
110 1111 (0x6F)
110 0110 (0x66)
110 0111 (0x67)
5.6
110 1110 (0x6E)
110 1111 (0x6F)
110 0110 (0x66)
110 0111 (0x67)
3.8
110 1110 (0x6E)
110 1111 (0x6F)
110 0110 (0x66)
110 0111 (0x67)
1.8
110 1110 (0x6E)
110 1111 (0x6F)
is powered from V
IO L
voltage.)
IO
supply from the EV kit, and make sure header jumper J2
IO
C slave address, switching current limit, and feedback configuration. A
(R9). The default R
SEL
R
SEL
(Ω)
3740
8060
12400
16900
21500
26100
30900
36500
42200
48700
56200
64900
75000
86600
100000
OPEN
MAX77857 Evaluation Kit
, eliminating the need for an external V
value installed on the EV kit is
SEL
EV Kit Software section for more information.
FEEDBACK
TYPICAL
RESISTOR
I (A)
LIM
SELECTION
7.0
5.6
External
feedback
resistors
3.8
1.8
. Also, install
IN
power
IO
. If you are
IO
2 C serial bus's
2
I C SLAVE
ADDRESS
(7-BIT)
110 0110 (0x66)
110 0111 (0x67)
110 1110 (0x6E)
(0x6E) (0x6E)
110 1111 (0x6F)
110 0110 (0x66)
110 0111 (0x67)
110 1110 (0x6E)
110 1111 (0x6F)
110 0110 (0x66)
110 0111 (0x67)
110 1110 (0x6E)
110 1111 (0x6F)
110 0110 (0x66)
110 0111 (0x67)
110 1110 (0x6E)
110 1111 (0x6F)
Analog Devices | 6