Datasheet

LTM4628
7
4628fe
For more information www.linear.com/LTM4628
PIN FUNCTIONS
V
OUT1
(A1-A5, B1-B5, C1-C4): Power Output Pins. Apply
output load between these pins and GND pins. Recommend
placing output decoupling capacitance directly between
these pins and GND pins. Review Table 4.
GND (A6-A7, B6-B7, D1-D4, D9-D12, E1-E4, E10-E12,
F1-F3, F10-F12, G1, G3, G10, G12, H1-H7, H9-H12, J1,
J5, J8, J12, K1, K5-K8, K12, L1, L12, M1 , M12): Power
Ground Pins for Both Input and Output Returns.
V
OUT2
(A8-A12, B8-B12, C9-C12): Power Output Pins.
Apply output load between these pins and GND pins. Rec-
ommend placing
output decoupling capacitance directly
between these pins and GND pins. Review Table 4.
V
OUTS1
, V
OUTS2
(C5, C8): This pin is connected to the top
of the internal top feedback resistor for each output. The
pin can be directly connected to its specific output, or
connected to DIFFOUT when the remote sense amplifier
is used. In paralleling modules, one of the V
OUTS
pins is
connected to the DIFFOUT pin in remote sensing or directly
to V
OUT
with no remote sensing. It is very important to
connect these pins to either the DIFFOUT or V
OUT
since
this is the feedback path, and cannot be left open. See the
Applications Information section.
f
SET
(C6): Frequency Set Pin. A 10µA current is sourced
from this pin. A resistor from this pin to ground sets a
voltage that in turn programs the operating frequency.
Alternatively, this pin can be driven with a DC voltage
that can set the operating frequency. See the Applications
Information section.
SGND (C7, D6, G6-G7, F6-F7): Signal Ground Pin. Return
ground path for all analog and low power circuitry. Tie a
single connection to the output capacitor GND in the ap
-
plication. See layout guidelines in Figure 27.
V
FB1
, V
FB2
(D5, D7): The Negative Input of the Error
Amplifier for Each Channel. Internally, this pin is con-
nected to
V
OUTS1
or V
OUTS2
with a 60.4kΩ precision
resistor. Different output voltages can be programmed
with an additional resistor between V
FB
and GND pins. In
PolyPhase
®
operation, tying the V
FB
pins together allows
for parallel operation. See the Applications Information
section for details.
(Recommended to Use Test Points to Monitor Signal Pin Connections.)
COMP1 and COMP2
vs Output Current
I
OUT1
and I
OUT2
vs Total Current
for Parallel Operation
TOTAL OUTPUT CURRENT (A)
0
I
OUT1
AND I
OUT2
(A)
7
8
16
4628 G16
6
5
0
3
4
8
12
2
6
10
14
4
1
2
9
I
OUT1
I
OUT2
OUTPUT CURRENT (A)
0
COMP (V)
1.2
1.3
9
4628 G17
1.1
1.0
0.5
0.8
2
4
6 81
3
5 7
0.9
0.6
0.7
1.4
V
ITH1
V
ITH2
TYPICAL PERFORMANCE CHARACTERISTICS