Datasheet

LTM8001
10
8001fb
For more information www.linear.com/LTM8001
BLOCK DIAGRAM
CURRENT
MODE
CONTROLLER
2.2µH
10k
0.2µF
2.2µF
V
IN0
RUN
COMP
ILIM
V
REF
SYNC
SS
R
SENSE
V
OUT0
V
OUT1
SET1
INTERNAL
REGULATOR
V
IN0
GND RT FB0 BIAS123 BIAS45 V
IN45
1.1A LDO
V
OUT2
SET2
1.1A LDO
V
OUT3
SET3
1.1A LDO
V
OUT4
SET4
1.1A LDO
V
OUT5
SET5
8001 BD
1.1A LDO
the absolute maximum voltage rating of 6V through a
resistor, provided the pin current does not exceed 100µA.
FB0 (Pin L5): The LTM8001 regulates its FB0 pin to 1.19V.
Connect the adjust resistor from this pin to ground. The
value of R
FB0
is given by the equation:
R
FBO
=
11.9
V
OUT
–1.19
where R
FB0
is in kΩ.
COMP (Pin L6): Compensation Pin. This pin is generally
not used. The LTM8001 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 P
WM comparator of the L
TM8001. In most cases,
no adjustment is necessary. If this function is not used,
leave this pin open.
RT (Pin L7): The RT pin is used to program the switch
-
ing frequency of the LTM8001 by connecting a resistor
from this pin to ground. The Applications Information
section of the data sheet includes a table to determine the
recommended resistance value and switching frequency
.
When using the SYNC function, set the frequency to be
20% lower than the SYNC pulse frequency
. Do not leave
this pin open.
ILIM (Pin L8): The ILIM pin reduces the maximum regulated
output current of the LTM8001. The maximum control volt
-
age range is 1.5V. ILIM voltages above 1.5V have little or
no effect. If this function is not used, tie this pin to V
REF
.
SET1, SET2, SET3, SET4, SET5 (Pins L9, H11, G11, D11,
A9): These pins set the regulation point for each LDO. A
fixed current of 10μA flows out of this pin through a single
external resistor, which programs the output voltage of
the device. Output voltage range is zero to the absolute
maximum rated output voltage. The transient performance
can be improved by adding a small capacitor from the
SET pin to ground.
V
OUT1
(Pins L10, L11), V
OUT2
(Pins J11, K11), V
OUT3
(Pins
E11, F11), V
OUT4
(Pins B11, C11), V
OUT5
(Pins A10, A11):
These are the power outputs of the individual LDOs. There
must be a minimum load current of 1mA or the output may
not regulate. The internal LDOs are rated for positive volt
-
ages between their inputs and outputs. Avoid applications
where the internal LDOs can
experience a negative voltage,
even during start-up and turn-off transients
PIN FUNCTIONS