LTM8026 LINER [Linear Technology], LTM8026 Datasheet - Page 10

• Manufacturer Part Number: LTM8026
• Description: 36VIN, 5A, 2-Quadrant CVCC Step-Down
• Manufacturer: LINER [Linear Technology]

pin FuncTions
LTM8052
V
capacitor and the output load between these pins and
GND pins. When reverse current is being driven into the
LTM8052’s output by the load, the energy is delivered back
through the LTM8052 and out to the V
taken to prevent excessive voltage if other devices on the
V
in the Applications Information section for more details
and circuit suggestions.
GND (Bank 2): Tie these GND pins to a local ground plane
below the LTM8052 and the circuit components. In most
applications, the bulk of the heat flow out of the LTM8052
is through these pads, so the printed circuit design has a
large impact on the thermal performance of the part. See
the PCB Layout and Thermal Considerations sections for
more details. Return the feedback divider (R
V
internal regulator and to the internal power switches. This
pin must be locally bypassed with an external, low ESR
capacitor; see Table 1 for recommended values.
CTL_T (Pin D8): Connect a resistor/NTC thermistor network
to the CTL_T pin to reduce the maximum regulated output
current of the LTM8052 in response to temperature. The
maximum control voltage is 1.5V. If this function is not
used, tie this pin to V
CTL_I (Pin E8): The CTL_I pin reduces the maximum
regulated output current of the LTM8052. The maximum
control voltage is 1.5V. If this function is not used, tie
this pin to V
V
Drive. It is valid when V
RT (Pin G8): The RT pin is used to program the switching
frequency of the LTM8052 by connecting a resistor from
this pin to ground. The Applications Information section of
the data sheet includes a table to determine the resistance
value based on the desired switching frequency. When us-
ing the SYNC function, apply a resistor value equivalent to
20% lower than the clock frequency applied to the SYNC
pin. Do not leave this pin open.
10
IN
OUT
IN
REF
(Bank 3): The V
bus cannot absorb this energy. See Input Precautions
(Pin F8): Buffered 2V Reference Capable of 0.5mA
(Bank 1): Power Output Pins. Apply the output filter
REF
.
IN
pins supply current to the LTM8052’s
REF
IN
.
> 6V and RUN is active high.
IN
pins. Care must be
ADJ
) to this net.
COMP (Pin H8): Compensation Pin. This pin is generally
not used. The LTM8052 is internally compensated, but
some rare situations may arise that require a modifica-
tion to the control loop. This pin connects directly to the
input PWM comparator of the LTM8052. In most cases,
no adjustment is necessary. If this function is not used,
leave this pin open.
SS (Pin J8): Soft-Start Pin. Place an external capacitor to
ground to ramp the output voltage during start-up condi-
tions. The soft-start pin has an 11µA charging current.
ADJ (Pin K8): The LTM8052 regulates its ADJ pin to 1.19V.
Connect the adjust resistor from this pin to ground. The
value of R
where R
RUN (Pin L6): The RUN pin acts as an enable pin and turns
on the internal circuitry. It may also be used to implement
a precision UVLO. See the Applications Information sec-
tion for details. The RUN pin is internally clamped, so it
may be pulled up to a voltage source that is higher than
the absolute maximum voltage of 6V through a resistor,
provided the pin current does not exceed 100µA. Do not
leave this pin open.
SYNC (Pin L7): Frequency Synchronization Pin. This pin
allows the switching frequency to be synchronized to an
external clock. The R
ate the internal clock at 20% lower than the SYNC pulse
frequency. This pin should be grounded when not in use.
Do not leave this pin floating. When laying out the board,
avoid noise coupling to or from the SYNC trace. See the
Synchronization section in Applications Information.
R
ADJ
ADJ
=
ADJ
V
OUT
is in kΩ.
is given by the equation:
11.9
– 1.19
T
resistor should be chosen to oper-
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