Linear Technology DC1041A-B - LTM4601HV Demo Board | 28VIN, 12A Step-Down μModule Regulator DC1041A-B DC1041A-B 数据表
产品代码
DC1041A-B
LT4356
2
Board Layout
D C1018B-B is a 4-layer board. There are planes for
input, output, drain and ground; these are replicated on
each layer.
The spare amplifier is kept active during shutdown in
the LT4356CD E-2, resulting in a supply current of
about 50µA.
The 93 mil input and output connection turrets are not
swaged and may be removed for attachment of up to
12 gauge wire. Banana jacks facilitate bench testing.
Sufficient copper is available to support applications of
at least 20A.
LED s are included as quick debug indicators. These
LED s show:
LED 1
D C1018B-B is a 4-layer board. There are planes for
input, output, drain and ground; these are replicated on
each layer.
The spare amplifier is kept active during shutdown in
the LT4356CD E-2, resulting in a supply current of
about 50µA.
The 93 mil input and output connection turrets are not
swaged and may be removed for attachment of up to
12 gauge wire. Banana jacks facilitate bench testing.
Sufficient copper is available to support applications of
at least 20A.
LED s are included as quick debug indicators. These
LED s show:
LED 1
12V input G reen
LED 3
12V output G reen
LED 4
FLT#
R ed
LED 5
EN
G reen
The enable and fault LEDs are both powered in such a
way that the signals present on their associated turrets
are limited in voltage (see schematic). To this end a
simple series regulator (Q 2 and D 6) has been included
on the demo board for powering the FLT# output; the
FLT# pin itself is rated to 80V.
R 8 is an optional pull-up resistor for the SH D N # pin.
M odifying Current Lim it
D C1018B-B is designed for 3.5A maximum load cur-
rent and may be modified for higher or lower current
levels. Sense resistor R SN S1-3 pads are designed for
1206 or 2010 sense resistors. The LT4356-2 current
sense voltage is 50mV, with limiting occurring at
50mV/R SN S. O ptional footprints for D 2-pak or S-8
M O SFETs allow for much higher or lower current lev-
els. Sufficient copper is present to handle in excess of
20A. If the S-8 footprint is used, move R 3 (10 ohms)
to the bottom of the board, R 3B. This is the gate resis-
tor for the S-8 M O SFET.
At higher currents the clamp D CL must be proportion-
ately increased. This catches the locally generated
spike at the M O SFET drain when the output goes into
regulation. The energy content of this spike is a direct
function of input slew rate and output load capacitance.
Changing Output Regulation Level
The output limiting or regulation voltage is easily modi-
fied by simply changing R 1 and R 2 to values appropri-
ate for the application. The FB pin servo voltage is
1.25V. See the data sheet for a full description of this
pin and equations. As built, the demo board clamps at
16V.
The actual operating voltage is independent of the
clamping voltage, and may be anything from the mini-
mum operating voltage of 4V up to the clamping volt-
age. Thus while the demo board is labeled "12V", it can
operate with any other sub-16V input such as a 5V
regulated supply, a 6V gelcell, or a stack of 8 NiM H
cells, or a 9V impedance limited wall cube, to name but
a few possible inputs.
Supply Current
The low shutdown current of the LT4356-2 is impossi-
ble to measure on the demo board because of the
presence of the input LED, LED 1, and the LED Supply.
R emove R 10 and R 17 to eliminate these paths.
At higher currents the clamp D CL must be proportion-
ately increased. This catches the locally generated
spike at the M O SFET drain when the output goes into
regulation. The energy content of this spike is a direct
function of input slew rate and output load capacitance.
Changing Output Regulation Level
The output limiting or regulation voltage is easily modi-
fied by simply changing R 1 and R 2 to values appropri-
ate for the application. The FB pin servo voltage is
1.25V. See the data sheet for a full description of this
pin and equations. As built, the demo board clamps at
16V.
The actual operating voltage is independent of the
clamping voltage, and may be anything from the mini-
mum operating voltage of 4V up to the clamping volt-
age. Thus while the demo board is labeled "12V", it can
operate with any other sub-16V input such as a 5V
regulated supply, a 6V gelcell, or a stack of 8 NiM H
cells, or a 9V impedance limited wall cube, to name but
a few possible inputs.
Supply Current
The low shutdown current of the LT4356-2 is impossi-
ble to measure on the demo board because of the
presence of the input LED, LED 1, and the LED Supply.
R emove R 10 and R 17 to eliminate these paths.
N ote that above 16V, D 4 will draw current. Below 16V
leakage in D 4, Q 2's collector-base junction in series
with D 6 and Q1 will add to the LT4356-2's supply cur-
rent. These effects are insignificant at room tempera-
ture.
leakage in D 4, Q 2's collector-base junction in series
with D 6 and Q1 will add to the LT4356-2's supply cur-
rent. These effects are insignificant at room tempera-
ture.