DC786A Linear Technology, DC786A Datasheet - Page 3

• Manufacturer Part Number: DC786A
• Description: LTC4260CGN 200W Positive 48V Hot Swap Controller With Current And Voltage Monitoring (req DC590)
• Manufacturer: Linear Technology
• Series: -r

Specifications of DC786A

• Main Purpose: Power Management, Hot Swap Controller
• Embedded: No
• Utilized Ic / Part: LTC4260
• Primary Attributes: 200W, 36 ~ 72 V
• Secondary Attributes: I²C Interface
• Kit Application Type: Power Management
• Application Sub Type: Hot-Swap Controller
• Kit Contents: Quick Eval Software
• Lead Free Status / Rohs Status: Not applicable / Not applicable

In high current applications do not forget to upgrade
Z1. If long leads are present between the LTC4260 and
load bypassing, install 10µF or more bypassing at
COUT to eliminate the chance of MOSFET oscillation
and large negative excursions at +48V/5A OUTPUT.
SHORT PINS
If your system uses a short pin to sense board inser-
tion, move JP1 to SHORT PIN and, using the SHORT
PIN turret, connect the aforementioned short pin. This
is a direct connection to the LTC4260's BD_PRST\ pin;
if deleterious voltages are anticipated, add a series re-
sistor and clamping. BD_PRST\ is good for -0.3 to
+12V on its own.
BD_PRST\ is also logic compatible, with a 1.235V
threshold and 130mV hysteresis.
PWRGD (GPIO)
Refer to the schematic. The LTC4260 GPIO pin defaults
to an open drain power good configuration, going high
when FB determines the output voltage is adequate. In
this configuration GPIO pulls low when power is bad,
and turns on D3. D3 pulls to the output rail, demon-
strating the high voltage capability of GPIO. If GPIO is
reconfigured as an input by I2C control or used as a
logic output, simply remove R4 (on the bottom of the
board).
PROBE GND
Use this if you need to refer measurements to the
LTC4260's ground. Do not connect power supplies
and loads to this ground.
INTVCC
INTVCC was included on the LTC4260 to allow bypass-
ing of the internal 5.5V supply rail for superior noise
immunity. It is also permissible to steal a small current
of up to 1mA off of the INTVCC pin to bias address
pins or ancillary circuits. A turret is provided for con-
nections to INTVCC.
CIN, COUT
The LTC4260 serves equally well on either side of the
connector; as a port on a backplane or as a card-
centric Hot Swap controller. Holes are included for ad-
dition of an input capacitor or load capacitor at CIN
and COUT. Do not neglect polarity markings.
ALERT\
If the evaluation software is set to free-run (using the
"Start" button), alert conditions will turn on D4 (red)
but just as quickly, D4 will extinguish when the soft-
ware polls the LTC4260. D4 therefore lights for only a
brief flash in the free-run mode. If you want to see it
stay lit, operate the software interface in "Refresh"
(manual) mode.
I2C PORT
If the I2C port (JP7) is disconnected, the turret termi-
nals SDAO, SDAI, and SCL can be connected directly
to an I2C bus. Power for D4-7 is supplied by JP7, so in
this mode the LEDs will not light. Setting JP3 SDA to
COM connects SDAO and SDAI together for communi-
cation to a non-isolated bus. Splitting SDAO and SDAI
facilitates optically isolated applications (see the
LTC4260 data sheet).
The I2C address is selected by using JP4, JP5 and JP6
to pull the address pins high, low, or allowing them to
float. An address table is shown in the data sheet. The
evaluation software automatically scans and identifies
the I2C address, regardless of the setting.
JUMPER SUMMARY
JP1 BD_PRST\:
ground or to the SHORT PIN turret. SHORT PIN is then
connected to logic, an opto isolator, a short pin, or an
insertion detection switch to initiate turn-on of the
LTC4260.
JP2 ON CONFIG: at start-up the LTC4260 operates in
one of two modes: in AUTO mode it turns on when
BD_PRST\ is grounded; in I2C mode it waits for
connects BD_PRST\ pin either to
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