Datasheet

LTC3880/LTC3880-1
13
3880fc
For more information www.linear.com/LTC3880
PIN FUNCTIONS
V
SENSE0
+
(Pin 1): Channel 0 Positive Voltage Sense
Input.
V
SENSE0
–
(Pin 2): Channel 0 Negative Voltage Sense
Input.
I
TH0
/I
TH1
(Pin 5/Pin 26 ): Current Control Threshold and
Error Amplifier Compensation Nodes. Each associated
channel’s current comparator tripping threshold increases
with its I
TH
voltage.
I
SENSE0
+
/I
SENSE1
+
(Pins 6/Pin 3): Current Sense Compara-
tor Inputs. The (+) inputs to the current comparators are
normally connected to DCR sensing networks or current
sensing resistors.
I
SENSE0
–
/I
SENSE1
–
(Pin 7/Pin 4): Current Sense Comparator
Inputs. The (–) inputs are connected to the low side of the
current sense element.
SYNC (Pin 8): External Clock Synchronization Input and
Open-Drain Output Pin. If an external clock is present at
this pin, the switching frequency will be synchronized to
the external clock. If clock master mode is enabled, this
pin will pull low at the switching frequency with a 500ns
pulse to ground. A resistor pull up to 3.3V is required in
the application if the LTC3880 is the master.
SCL (Pin 9): Serial Bus Clock Input. Open-drain output,
can hold the output low if clock stretching is enabled. A
pull-up resistor to 3.3V is required in the application.
SDA (Pin 10): Serial Bus Data Input and Output. A pull-up
resistor to 3.3V is required in the application.
ALERT (Pin 11): Open-Drain Digital Output. Connect the
SMBALERT signal to this pin. A pull-up resistor to 3.3V
is required in the application.
GPIO0/GPIO1 (Pin 12/Pin 13): Digital Programmable
General Purpose Inputs and Outputs. Open-drain output.
A pull-up resistor to 3.3V is required in the application.
RUN0/RUN1 (Pin 14/Pin 15): Enable Run Input. Logic high
on these pins enables the controller. Open-drain output
holds the pin low until the LTC3880 is out of reset. A pull-
up resistor to 3.3V is required in the application.
ASEL (Pin 16): Serial Bus Address Configuration Input.
Connect a ±1% resistor divider between the chip V
DD25
ASEL and SGND in order to select the 4LSBs of the se-
rial bus interface address. A resistor divider on ASEL is
recommended
if
there are more than 1 LTC3880 on the
same board to assure the user can independently program
each IC. If the pin is left open, the IC will use the value
programmed in the NVM. Minimize capacitance when the
pin is open to assure accurate detection of the pin state.
TYPICAL PERFORMANCE CHARACTERISTICS
DC Output Current Matching in a
2-Phase System (LTC3880)
TOTAL CURRENT (A)
0
CHANNEL CURRENT (A)
15
20
25
15 25 40
3880 G28
10
5
0
5 10
20
30 35
CHAN 0
CHAN 1
Dynamic Current Sharing During a
Load Transient in a 4-Phase System
10
0
CURRENT
5A/DIV
5µs/DIV
3880 G29
10
0
CURRENT
5A/DIV
5µs/DIV
3880 G30
Dynamic Current Sharing During a
Load Transient in a 4-Phase System