LTC3865IFE#PBF Linear Technology, LTC3865IFE#PBF Datasheet - Page 9

• Manufacturer Part Number: LTC3865IFE#PBF
• Description: IC BUCK SYNC ADJ DUAL 38TSSOP
• Manufacturer: Linear Technology
• Type: Step-Down (Buck)r

Specifications of LTC3865IFE#PBF

• Internal Switch(s): No
• Synchronous Rectifier: Yes
• Number Of Outputs: 2
• Voltage - Output: 0.6 ~ 5 V
• Frequency - Switching: 250kHz ~ 770kHz
• Voltage - Input: 4.5 ~ 38 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 38-TSSOP Exposed Pad, 38-eTSSOP, 38-HTSSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Power - Output: -

PIN FUNCTIONS
V
internal programmable resistive divider is used, these
pins must be connected to their corresponding outputs.
When an external resistive divider is used, these pins are
used for error amplifi er feedback inputs. They receive
the remotely sensed feedback voltages for each channel
directly from the outputs or from the external divider
across the outputs.
TK/SS1, TK/SS2 (Pins 2, 7/Pins 6, 12): Output Voltage
Tracking and Soft-Start Inputs. When one channel is
confi gured to be master of the two channels, a capacitor
to ground at this pin sets the ramp rate for the master
channel’s output voltage. When a channel is confi gured
to be the slave of the two channels, the output voltage
ramp of the master channel can be reproduced by a re-
sistor divider and applied to this pin of the slave channel.
Internal soft-start currents of 1.3μA charge the soft-start
capacitors.
I
and Error Amplifi er Compensation Points. Each associated
channels’ current comparator tripping threshold increases
with its I
VID11, VID12, VID21, VID22 (Pins 4, 5, 12, 28/ Pins 9,
10, 18, 37): VID Inputs for Output Voltage Programming.
Tie these pins to INTV
set the output voltages.
I
tor Sense Voltage Range Inputs. This pin can be tied to
SGND, FLOAT or INTV
sense threshold for each comparator. Current compara-
tor sense voltage range of the LTC3865-1 is set to default
value of 50mV.
PGOOD (Pin 14 LTC3865/NA): Co-Bonded Power Good
Indicator Output for LTC3865 in QFN Package. Open-drain
logic output that is pulled to ground when either channel
output exceeds ±10% regulation window, after the internal
20μs power bad mask timer expires.
TH1
LIM
OSENSE1
, I
(Pin 13/Pin 19) (LTC3865 Only): Current Compara-
TH2
TH
, V
(Pins 3, 6/Pins 7, 11): Current Control Thresholds
control voltage.
OSENSE2
(Pins 1, 8/Pins 5, 13): When the
CC
CC
, GND or leave them fl oating to
to set the maximum current
(QFN/TSSOP)
PGOOD1, PGOOD2 (Pins 14, 13 LTC3865-1/Pins 21, 20):
Separate Power Good Indicator Outputs for LTC3865-1 in
QFN package and LTC3865 in FE package. Open-drain logic
output that is pulled to ground when the corresponding
channel output exceeds ±10% regulation window, after
the internal 20μs power bad mask timer expires.
PGND (Pin 18/NA): Power Ground Pin. Connect this pin
closely to the sources of the bottom N-channel MOSFETs,
the (–) terminal of C
EXTV
nal Switch Connected to INTV
supplies the IC power, bypassing the internal low dropout
regulator, whenever EXTV
exceed 6V on this pin.
INTV
control circuits are powered from this voltage. Decouple
this pin to PGND with a minimum of 4.7μF low ESR tan-
talum or ceramic capacitor.
V
to PGND with a capacitor (0.1μF to 1μF).
BG1, BG2 (Pins 23, 19/Pin 31, 27): Bottom Gate Driver
Outputs. These pins drive the gates of the bottom N-chan-
nel MOSFETs between PGND and INTV
BOOST1, BOOST2 (Pins 24, 17/Pins 33, 25): Boosted
Floating Driver Supplies. The (+) terminal of the booststrap
capacitors connect to these pins. These pins swing from a
diode voltage drop below INTV
TG1, TG2 (Pins 25, 16/Pins 34, 23): Top Gate Driver
Outputs. These are the outputs of fl oating drivers with
a voltage swing equal to INTV
switch nodes voltages.
SW1, SW2 (Pins 26, 15/Pins 35, 22): Switch Node
Connections to Inductors. Voltage swing at these pins
is from a Schottky diode (external) voltage drop below
ground to V
IN
(Pin 22/Pin 30): Main Input Supply. Decouple this pin
CC
CC
(Pin 21/Pin 29): Internal 5V Regulator Output. The
(Pin 20/Pin 28): External Power Input to an Inter-
IN
.
LTC3865/LTC3865-1
VCC
and the (–) terminal of C
CC
is higher than 4.7V. Do not
CC
CC
CC
. This switch closes and
up to V
superimposed on the
CC
IN
.
+ INTV
IN
CC
.
3865fb
.
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