Lineage Power

8

Data Sheet

October 14, 2009

5 Vdc Input; 1.5 Vdc to 3.3 Vdc Output; 20 W

NH020-Series Power SIPs:

Test Configurations

Note: Measure input reflected ripple current with a simulated source

battery impedance. Measure current as shown above.

Figure 14. Input Reflected Ripple Current Test Setup.

Note: Scope measurements should be made using a BNC socket,

with a 47 µF tantalum capacitor .Position the load between 51

mm and 76 mm (2 in and 3 in) from the module

Figure 15. Peak-to-Peak Output Ripple Measurement

Test Setup.

Note: All voltage measurements to be taken at the module termi-

nals, as shown above. If sockets are used then Kelvin con-

nections are required at the module terminals to avoid

measurement

errors due to socket contact resistance.

Figure 16. Output Voltage and Efficiency Test Setup.

Design Considerations

Input Source Impedance

The power SIP should be connected to a low ac- impedance

input source. Highly inductive source impedances can affect

the stability of the SIP. Adding external capacitance close to

the input pins of the SIP can reduce the ac impedance and

ensure system stability. The minimum recommended input

capacitance (C1) is a 100 µF electrolytic capacitor (see Fig-

ures 17 and 19).

Input Ripple Voltage .

To reduce the amount of ripple current fed back to the input

supply (input reflected-ripple current), an external input filter

can be added. Up to 10 µF of ceramic capacitance (C2) may

be externally connected to the input of the SIP, provided the

source inductance (LSOURCE) is less than 1 µH (see Figure

17).

To further reduce the input reflected-ripple current, a

filter inductor (LFILTER) can be connected between the sup-

ply and the external input capacitors (see Figure 18).

As mentioned above, a 100 µF electrolytic capacitor (C1)

should be added across the input of the SIP to ensure stabil-

ity of the unit. The electrolytic capacitor should be selected

for ESR and RMS current ratings to ensure safe operation in

the case of a fault condition. Refer to Figure 19 for the

appropriate electrolytic capacitor ratings.

When using a tantalum input capacitor, take care not to

exceed device power rating because of the capacitor’s fail-

ure mechanism (for example, a short circuit). The

filter inductor should be rated to handle the maximum power

SIP input current of 6.1 Adc.

If the amount of input reflected-ripple current is unaccept-

able with an external L-C filter, more capacitance may be

added across the input supply to form a C-L-C filter. For best

results, the filter components should be mounted close to

the power SIP.

T O OSC ILLOSC OPE

500 nH

ESR < 0.1 •

@ 20 °C , 100 k H z

BAT T ER Y

L

η

V

O(+)

V

O(-)

–

[] I

O

×

V

I(+)

V

I(-)

–

[] I

I

×

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⎝⎠

⎛⎞

100

×

=