CAPZero Family
1
Zero Loss Automatic X Capacitor Discharge IC
Product Highlights
R1
Blocks current through X capacitor discharge resistors when AC
voltage is connected
D1
Automatically discharges X capacitors through discharge resistors
when AC is disconnected
MOV
Simplifies EMI filter design larger X capacitor allows smaller
and Other
AC
X Capacitor
EMI Filter
inductive components with no change in consumption
Components
Only two terminals meets safety standards for use before or after
system input fuse
>4 mm creepage on package and PCB
D2
CAPZero
Self supplied no external bias required
R2
High common mode surge immunity no external ground
connection PI-6599-110711
High differential surge withstand 1000 V internal MOSFETs
Figure 1. Typical Application Not a Simplified Circuit.
EcoSmart Energy Efficient
<5 mW consumption at 230 VAC for all X capacitor values
Applications
Component Selection Table
All ACDC converters with X capacitors >100 nF
Appliances requiring EuP Lot 6 compliance
Total Series
Maximum Total
3 2
Adapters requiring ultra low no-load consumption
Product BV Resistance
DSS
X Capacitance
All converters requiring very low standby power
(R1 + R2)
CAP002DG 825 V
Description
500 nF 1.5 M W
CAP012DG 1000 V
When AC voltage is applied, CAPZero blocks current flow in the X
capacitor safety discharge resistors, reducing the power loss to less CAP003DG 825 V
750 nF 1.02 M W
1
than 5 mW, or essentially zero at 230 VAC. When AC voltage is
CAP013DG 1000 V
disconnected, CAPZero automatically discharges the X capacitor by
CAP004DG 825 V
connecting the series discharge resistors. This operation allows total
1 mF 780 k W
flexibility in the choice of the X capacitor to optimize differential mode CAP014DG 1000 V
EMI filtering and reduce inductor costs, with no change in power
CAP005DG 825 V
consumption. 1.5 mF 480 k W
CAP015DG 1000 V
Designing with CAPZero is simply a matter of selecting the appropriate
CAP006DG 825 V
CAPZero device and external resistor values in Table 1 for the
2 mF 360 k W
CAP016DG 1000 V
X capacitor value being used. This design choice will provide a worst
case RC time constant, when the AC supply is disconnected, of less
CAP007DG 825 V
2.5 mF 300 k W
than 1 second as required by international safety standards.
CAP017DG 1000 V
The simplicity and ruggedness of the two terminal CAPZero IC makes it
CAP008DG 825 V
3.5 mF 200 k W
an ideal choice in systems designed to meet EuP Lot 6 requirements.
CAP018DG 1000 V
The CAPZero family has two voltage grades: 825 V and 1000 V. The
CAP009DG 825 V
5 mF 150 k W
voltage rating required depends on surge requirement and circuit
CAP019DG 1000 V
configuration of the application. See Key Applications Considerations
section for details.
Table 1. Component Selection Table.
Notes:
1. IEC 62301 clause 4.5 rounds standby power use below 5 mW to zero.
2. Values are nominal. RC time constant is <1 second with 20% X capacitor
and 5% resistance from these nominal values.
3. Packages: D: SO-8.
www.power.com July 2015CAPZero
For MOV placement that is not directly across the X Capacitor1 (for
Pin Functional Description
example MOV in Figure 3) the 1000 V CAPZero devices can be
POS2
The pin configuration of Figure 2 ensures that the width of the SO-8
used up to a surge specification of 1.5 kV. For differential surge
package is used to provide creepage and clearance distance of over
voltage specifications of >1.5 kV it is recommended that the MOV is
4 mm.
always placed in the location shown in Figure 3 as MOV .
POS1
Although electrical connections are only made to pins 2, 3, 6 and 7, it
It is always recommended that the peak voltage between terminals
is recommended that pins 1-4 and pins 5-8 are coupled together on
D1 and D2 of CAPZero is measured during surge tests in the final
the PCB see Applications Section.
system. Measurements of peak voltage across CAPZero during surge
tests should be made with oscilloscope probes having appropriate
voltage rating and using an isolated supply to the oscilloscope to
avoid ground currents influencing measurement results. When
making such measurements, it is recommended that 50 V engineer-
D Package (SO-8)
ing margin is allowed below the breakdown voltage specification (for
example 950 V with the 1000 V CAPZero).
1 8
NC NC
If the measured peak Drain voltage exceeds 950 V, an external 1 kV
2 7
ceramic capacitor of value up to 47 pF can also be placed between D1
D1 D2
and D2 terminals to attenuate the voltage applied between the
3 6
D1 D2
CAPZero terminals during surge. This optional external capacitor
4 5
placement is shown as C in Figure 3. It should be noted that use
NC NC EXT
of an external capacitor in this way will increase power consumption
slightly due to the C charge/discharge currents flowing in R1 and
EXT
R2 while AC is connected. A C value of 33 pF will add approximately
EXT
0.5 mW at 230 VAC, 50 Hz.
PI-5608-060810
PCB Layout and External Resistor Selection
Figure 2. Pin Configuration.
Figure 4 shows a typical PCB layout configuration for CAPZero. The
external resistors in this case are divided into two separate surface
Key Application Considerations mount resistors to distribute loss under fault conditions for example
where a short-circuit exists between CAPZero terminals D1 and D2.
Breakdown Voltage Selection
R1 and R2 values are selected according to Table 1.
Figure 3 illustrates possible system configurations influencing the
choice of CAPZero breakdown voltage. The system configuration Under a fault condition where CAPZero terminals D1 and D2 are
shorted together, each resistor will dissipate a power that can be
variables include the placement of the system MOV and X capacitor(s)
calculated from the applied AC voltage and the R1 and R2 values. For
as well as the differential surge voltage specifications of the
example in an application using CAP004 or CAP014, R1=R2=390 k W.
application.
If CAPZero is shorted out at 265 VAC R1 and R2 will each dissipate
As shown in Table 1, each device in the CAPZero family has a 825 V
45 mW.
or 1000 V option. For applications where the system MOV is placed
Resistors R1 and R2 should also be rated for 50% of the system input
in position 1 (MOV in Figure 3), the 825 V option will typically
POS1
voltage again to allow for the short-circuitry of CAPZero D1 to D2 pins
provide adequate voltage withstand for surge requirements up to 3 kV
during single point fault testing.
or more. The 1 kV CAPZero would be recommended for higher surge
requirements or if additional voltage margin is required.
R1
D1
MOV MOV
POS1 POS2
Other EMI
C
EXT
AC
Filter
Components
X Capacitor1 X Capacitor2
D2
CAPZero
R2
PI-6600-110711
Figure 3. Placement Options of MOV and C .
EXT
2
Rev. G 07/15 www.power.com