LTM4600HV
7
4600hvfe
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V
IN
(Bank 1): Power Input Pins. Apply input voltage
between these pins and GND pins. Recommend placing
input decoupling capacitance directly between V
IN
pins
and GND pins.
f
ADJ
(Pin A15): A 110k resistor from V
IN
to this pin sets
the one-shot timer current, thereby setting the switch-
ing frequency. The LTM4600HV switching frequency is
typically 850kHz. An external resistor to ground can be
selected to reduce the one-shot timer current, thus lower
the switching frequency to accommodate a higher duty
cycle step down requirement. See the applications section.
SV
IN
(Pin A17): Supply Pin for Internal PWM Controller.
Leave this pin open or add additional decoupling capacitance.
EXTV
CC
(Pin A19): External 5V supply pin for controller. If
left open or grounded, the internal 5V linear regulator will
power the controller and MOSFET drivers. For high input
voltage applications, connecting this pin to an external
5V will reduce the power loss in the power module. The
EXTV
CC
voltage should never be higher than V
IN
.
V
OSET
(Pin A21): The Negative Input of The Error Amplifier.
Internally, this pin is connected to V
OUT
with a 100k preci-
sion resistor. Different output voltages can be programmed
with additional resistors between the V
OSET
and SGND pins.
COMP (Pin B23): Current Control Threshold and Error
Amplifier Compensation Point. The current comparator
threshold increases with this control voltage. The voltage
ranges from 0V to 2.4V with 0.8V corresponding to zero
sense voltage (zero current).
SGND (Pin D23): Signal Ground Pin. All small-signal
components should connect to this ground, which in turn
connects to PGND at one point.
RUN/SS (Pin F23): Run and Soft-Start Control. Forcing
this pin below 0.8V will shut down the power supply.
Inside the power module, there is a 1000pF capacitor
which provides approximately 0.7ms soft-start time with
200µF output capacitance. Additional soft-start time can
be achieved by adding additional capacitance between
the RUN/SS and SGND pins. The internal short-circuit
latchoff can be disabled by adding a resistor between this
pin and the V
IN
pin. This resistor must supply a minimum
5µA pull up current. The RUN/SS pin has an internal 6V
Zener to ground.
FCB (Pin G23): Forced Continuous Input. Grounding this
pin enables forced continuous mode operation regardless
of load conditions. Tying this pin above 0.63V enables
discontinuous conduction mode to achieve high efficiency
operation at light loads. There is an internal 4.75K resistor
between the FCB and SGND pins.
PGOOD (Pin J23): Output Voltage Power Good Indicator.
When the output voltage is within 10% of the nominal
voltage, the PGOOD is open drain output. Otherwise, this
pin is pulled to ground.
PGND (Bank 2): Power ground pins for both input and
output returns.
V
OUT
(Bank 3): Power Output Pins. Apply output load
between these pins and GND pins. Recommend placing
High Frequency output decoupling capacitance directly
between these pins and GND pins.
(See Package Description for Pin Assignment)
pin FuncTions
E
C
A
RUN/SS
FCB
PGOOD
V
IN
BANK 1
PGND
BANK 2
V
OUT
BANK 3
COMP
SGND
EXTV
CC
V
OSET
f
ADJ
SV
IN
3 5
2 4
7 9
6 8
11 13
10 12
15 17
14 16
19 21
18 20 22
94
95 96 97 98
99 100 101 102 103
104
93
82
71
60
49
24
23
22
21
20
1918171676543
2
40
51
62
73
84 85 86 87 88 89 90 91
74 75 76 77 78 79 80
63 64 65 66 67 68 69
52 53 54 55 56 57 58
42 43 44 45 46 47
92
81
70
59
48
11109
13 14 15
26 27 28 29 30 31
33 34 35 36 37 38
41
1
8
12
25
32
39
50
61
72
83
1 23
B
D
F
G
H
J
L
M
N
P
R
T
K
4600hv PN01
