SMT4214 Summit Microelectronics, Inc., SMT4214 Datasheet - Page 12

• Manufacturer Part Number: SMT4214
• Description: Expandable Four-rail Supply TRAKKER™ Controller
• Manufacturer: Summit Microelectronics, Inc.

DEVELOPMENT HARDWARE & SOFTWARE (Cont.)
APPLICATIONS INFORMATION
shown in Figure 8A and 8B. Additional optional noise
bypassing components are shown for the VIX and
VOX pins. These components consist of ferrite bead
inductors and capacitors. They may be necessary in
very
tolerances are needed.
start mode.
should be set to minimum, and the VO and VI inputs
should be tied to VDD_CAP.
drive the gates of the power mosfets. Gate capacitors
(C23 thru C30) are also recommended to prevent
initial mosfet turn-on during the SMT4214 power on
sequence. To minimize transient power surges in hot-
Summit Microelectronics, Inc
Figure 7B – An alternative connection between the SMX3200 Programmer and SMT4214 I
connections.
position of the external PWR_ON# control signal or switch (S1). The zener diode (D3) provides further
protection by clamping the output voltage at 5.6V.
An example master/slave application circuit is
All unused channels must be programmed to soft-
The VGATE output pins require series resistors to
noisy
systems
The thresholds for unused channels
Although this alternative requires additional components, it will work regardless of the
Com m on
Ground
where
V D D _C AP
tight
SM T4214
undervoltage
G N D
P W R _O N #
2061 1.0 8/16/02
S D A
M R #
S C L
R2
swappable line card designs, place a 0.01µF (10nF),
25V, ceramic capacitor on each VGATE output pin to
ground.
10.5V or 14V depending on the type of mosfet. To
minimize the voltage drop across the Mosfet, it needs
to be fully enhanced to minimize RDS
some mosfets have maximum VGS specifications of
15V while others are 20V.
performance with the SMT4214, it is recommended to
use the lower rated VGS devices with the VGATE
output levels set to 10.5V instead of 14V. The industry
trend for power mosfets is toward lower VGS specs
while also maintaining low RDS
4.7k
The VGATE output level is programmable to either
S1
D1
10
Ω
8
6
4
2
Zener
5.6V
9
7
5
3
1
D3
0.1
C1
4.7k
µ
R1
F
Ω
0.1
C2
Preliminary Information
µ
D2
For improved tracking
(ON)
F
specifications.
SMT4214
2
(ON)
C serial bus
. However,
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