Block diagrams and pin connections SRK2001
4/20 DocID027367 Rev 4
Figure 3. Pin connections (top view)
(1
352*
*'
696
'96
9&&
*1'
*'
696
'96
$0
Table 2. Pin functions
No. Name Function
1VCC
Supply voltage of the device. A bypass capacitor to GND, located as close to IC's pins as possible,
helps to get a clean supply voltage for the internal control circuitry and acts as an effective energy
buffer for the pulsed gate drive currents.
2GND
Return of the device bias current and return of the gate drive currents. Route this pin to the common
point where the source terminals of both synchronous rectifier MOSFETs are connected.
3
(8)
GD1
(GD2)
Gate driver output for section 1 (2). Each totem pole output stage is able to drive power MOSFETs
with high peak current levels. To avoid excessive gate voltages in case the device is supplied with
a high V
CC
, the high level voltage of these pins is clamped to about 11 V. The pin has to be
connected directly to the SR MOSFET gate terminal.
4
(7)
SVS1
(SVS2)
Source voltage sensing for section 1 (2): it is the reference voltage of the corresponding drain
sensing signal on the DVS1, 2 pin. These pins have to be connected directly to the respective source
terminals of the corresponding synchronous rectifier MOSFET.
5
(6)
DVS1
(DVS2)
Drain voltage sensing for section 1 (2). These pins have to be connected to the respective drain
terminals of the corresponding synchronous rectifier MOSFET using a series resistor at least of
100 .
9PROG
Programming pin for conduction duty cycle at sleep mode entering/exiting. A resistor connected from
this pin to GND, supplied by an internal precise current source, sets a voltage V
PROG
; depending on
this voltage level, during the startup phase, the user can chose, according to the application
requirements, the proper sleep mode or burst mode exiting the conduction duty cycle among the
ones contained into two internal lookup tables (the values are predefined inside Table 6 on page 15,
Table 7 on page 15 and Table 8 on page 16). See Tabl e 5 or the proper choice of resistor value.
10 EN
Enable pin function with internal pull-up and current source capability:
– Automatic sleep mode function enable/disable: the sleep mode is disabled if the pin voltage is
detected above an internal threshold (V
SM_off
) during the startup phase.
– Remote ON/OFF: during run the mode, when the pin voltage is sensed below the internal
threshold V
EN_OFF
, the controller stops operating and enters a low consumption state; it resumes
the operation if the pin voltage surpasses the threshold V
EN_ON
.
– During the startup phase, the pin voltage level allows to select the predefined conduction duty
cycle for sleep mode entering. A resistor connected from this pin to GND, supplied by an internal
precise current source allows the user for this choice (two predefined values). See the Table 5 for
the proper choice of resistor value.
