SEN012DG Power Integrations, SEN012DG Datasheet - Page 3

• Manufacturer Part Number: SEN012DG
• Description: PMIC Solutions SENZero 2 Chan, Discon IC
• Manufacturer: Power Integrations
• Series: SENZero®r

Specifications of SEN012DG

• Mounting Style: SMD/SMT
• Input Voltage: - 0.3 V to + 6.5 V
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 40 C
• Output Current: 1 mA
• Supply Current: 0.5 mA
• Topology: Buck (Step-Down)
• Package / Case: SO-8
• Applications: Power Supply Controller
• Voltage - Input: -
• Voltage - Supply: 6 V ~ 16 V
• Current - Supply: 500µA
• Operating Temperature: -40°C ~ 105°C
• Mounting Type: Surface Mount
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Applications Considerations
The maximum voltage that the device can sustain across the
VCC and G pin is 16 V. The maximum voltage that any of the
source channels can be at with respect to the ground terminal
is 6.5 V. SENZero has a typical on state resistance of approxi-
mately 500 W at room temperature. The device is therefore
typically used in series with high ohmic value resistors where
this on resistance is a small percentage of the total series
impedance.
It is not necessary to provide a local bypass capacitor on the
VCC pin.
Operating Configurations for the SENZero
One configuration to power up the SENZero is shown in Figure 7.
In this circuit, SENZero is powered up from an unregulated bias
winding through a simple series pass regulator formed by Q1,
R
even if the maximum bias voltage exceeds 16 V. During power
down, as soon as the bias voltage falls below V
turn off.
The series pass transistor Q1 is necessary only if the bias
winding voltage regulation is not tight enough (unregulated). If
the voltage on the bias winding is regulated or is such that the
voltage on the VCC pin can be maintained in the range 6 V <
VCC < 16 V, then the series pass transistor (Q1, R
be eliminated.
Figure 7.
www.powerint.com
B
Unregulated
and V
Bias
Z
SENZero Powered from an Unregulated Bias Winding Through a Series
Pass Regulator. Device is Enabled When Bias Voltage is Present.
. This configuration ensures the VCC voltage is limited
(2 kΩ)
R
B
(2N3904)
Q1
V
Z
VCC
G
D1
S1
Z
, SENZero will
B
PI-6052-072010
and V
D2
S2
SENZero
Z
) can
A configuration that can be used to trigger remote-off
functionality is shown in Figure 8. In this configuration, a
regulated auxiliary output is used to power the IC. Transistor
Q1 serves as the ON/OFF switch which is commanded by the
Enable/Disable signal at its base.
Figure 8.
An alternative remote-off configuration is shown in Figure 9
where an unregulated bias voltage supplies the SENZero
through a series pass regulator similar to the one shown in
Figure 7. However the circuit of Figure 9 includes an ON/OFF
transistor Q2. In other versions of this circuit Q2 can be
replaced by an optocoupler allowing the ON/OFF disable signal
to be communicated from a secondary of the power supply
such as in PC power supplies.
Figure 9.
Regulated
Auxiliary
Unregulated
ON/OFF
Bias
SENZero Powered From a Regulated Auxiliary Winding.
Through a Series Pass Regulator. Transistor Q2 Provides Remote-Off
Functionality.
A Modified Version of an Unregulated Bias Winding Supplying Power
(2N3906)
Enable
(20 kΩ)
Q2
R
ON/OFF
A
(100 kΩ)
(2N3906)
Disable
R
B
Q1
(2 kΩ)
R
(2 kΩ)
B
R
(2N3904)
B
Q1
V
Z
VCC
SEN012-013
G
VCC
G
S1
D1
D1
S1
PI-6051-072010
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D2
S2
D2
S2
Rev. B 11/05/10
SENZero
SENZero
3