ZY1207 Power-One, ZY1207 Datasheet - Page 15

• Manufacturer Part Number: ZY1207
• Description: 3v To 14v Input 0.5v To 5.5v Output
• Manufacturer: Power-One

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9.
9.1
Margining can be implemented either by changing
the trim voltage as described in the previous
paragraph or by changing the resistance between
the REF and TRIM pins.
In the schematic shown in Figure 19, the nominal
output voltage is set with the trim resistor R
calculated from the equation in the paragraph 8.12.
Resistors R
output voltage up and down respectively and
determined from the equations below.
where R
ûV% is the absolute value of desired margining
expressed in percents of the nominal output voltage.
During normal operation the resistors are removed
from the circuit by the switches.
Down” switch is normally closed shorting the resistor
REV. 1.3 MAR 27, 2006
Up Switch
Margining
(normally
open)
Application Information
R
R
Output Voltage Margining
UP
DOWN
TRIM
Figure 19. Margining Configuration
20
UP
20
is the value of the trim resistor in k and
R
u
and R

UP
Down Switch
20
R
R
Margining
(normally
closed)
TRIM
TRIM

R
DOWN
TRIM
u
§
¨ ¨
©
5
R
are added to margin the
u
u
R
DOWN
R
TRIM
§
¨
©
100
TRIM
'
V
'

%
V

'
%
The “Margining
'
REF
TRIM
PGND
V
V
%
%
·
¸
¹
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·
¸ ¸
¹
, k
, k
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POL
TRIM
3V to 14V Input
R
open disconnecting the resistor R
An alternative configuration of the margining circuit is
shown in Figure 20.
switches
advantageous in some implementations.
R
from the following equations:
Caution:
Refer to No-Bus
Application Note on
application information on this and other product
features.
Up Switch
Margining
ZY1207 7A No-Bus POL Data Sheet
(normally
DOWN
UP
open)
and R
R
Figure 20. Alternative Margining Configuration
R
UP
while the “Margining Up” switch is normally
DOWN
Noise injected into the TRIM node may affect accuracy
of the output voltage and stability of the POL
converter. Always minimize the PCB trace length from
the TRIM pin to external components to avoid noise
pickup.
DOWN
are
20
Down Switch
20
R
Margining
(normally
u

UP
open)
for this configuration are determined
20
20
R
R
TM
normally
TRIM
TRIM
u

POL Converters. Z-1000 Series
R
R
www.power-one.com
x
TRIM
TRIM
u
0.5V to 5.5V Output
§
¨ ¨
©
In this configuration both
5
R
u
R
u
open
TRIM
DOWN
§
¨
©
R
100
TRIM
'
Page 15 of 18
V
'
UP

V
%
.

'
%
that
'
V
REF
TRIM
PGND
V
%
%
·
¸
¹
·
¸ ¸
¹
, k
may
for more
, k
POL
be