Datasheet

TPS5103
MULTIPLE MODE SYNCHRONOUS DC/DC CONTROLLER
SLVS240A – SEPTEMBER 1999 – REVISED MAY 2001
19
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
APPLICATION INFORMATION
overshoot of output rectangle wave
The drivers in the TPS5103 controller are fast and can produce high transients on V
CC
or the junction of Q1 and
Q2 (shown below). Care must be taken to insure that these transients do not exceed the absolute maximum
rating for the device or associated external component. A low-ESR capacitor connected directly from Q1 drain
to Q2 source can greatly reduce transient pulses on V
CC
. Also, Q1 turnon speed can be reduced by adding a
resistor (5 – 15 Ω) in series with OUT_u. Poor layout of the switching node (V1 in Figure 36) can result in the
requirement for additional snubber circuitry required from V1 to ground.
V
CC
OUT_u
Q1
V1
Q2
C1
Figure 36. Output Rectangle Wave
The high-current Schottky diode (D1) can be removed provided an alternate way of preventing negative
voltages on LL (≥0.5 V) is used (refer to Figure 38).
OUT_u
Q1
Q2
LL
D1
R
g
Figure 37. High-Current Schottky Diode