Y5117P Datasheet, PDF (8/14 Pages) Power-One – 3.0V to 13.2V Input 0.7V to 3.63V Output

Y5117 17A DC-DC POL Data Sheet
3.0V to 13.2V Input • 0.7V to 3.63V Output
6. Feature Description
6.1 Enable
This function allows the converter to be turned on or off
remotely. The Enable pin is internally pulled up to the
input voltage. It is recommended to control the Enable
pin with an open collector transistor. The saturation
voltage of the transistor shall be less than 0.55V at 1mA
to reliably turn the converter OFF.
The Enable pin of Y5117P can be left floating, if not
used. The Enable pin of Y5117PC shall be pulled low
until the input voltage reaches 6V.
6.2 Internal Supply Voltage (V_LDO)
If the input voltage is lower than 5.2V, then the V_LDO
pin is required to be connected to an external voltage
source (≥5.2V). This voltage should not exceed 15V
and be capable of supplying 60mA.
6.3 Undervoltage Lockout
The undervoltage lockout scheme monitors the input
voltage applied to it and does not allow the converter
to start when V_IN is less than the UVLO threshold.
When the input voltage is higher than 5.2V, the V_LDO
pin is connected to the input voltage. When the input
voltage is below 5.2V, the V_LDO pin is connected to an
external voltage source. UVLO turn-on threshold is
then set with the 10kOhm resistor connected between
the Enable pin and the ground as shown in Figure 12.
6.4 Output Voltage Trim
The output voltage is preset to 1.3V. The trim feature
allows the user to adjust the output voltage from this
nominal value.
Increase V_OUT: Trim range 1.3V < V_OUT ≤ 3.63V. An
external resistor (R_TU) is placed between the Trim pin
and the –Vs (negative voltage sense) pin.
R_TU = 137.5/(V_OUT-1.3), kΩ
Decrease V_OUT: Trim range 0.7V ≤ V_OUT < 1.3V.
An external resistor (R_TD) is placed between Trim pin
and V_REF pin.
R_TD = 110(V_REF – 1.25) / (1.3 – V_OUT) kΩ
Note that V_OUT cannot exceed 0.7V_IN.
An internal 5V (+/-2.5%) reference voltage is available
from V_REF (pin 19). Alternatively, an external
reference voltage can be used for better accuracy
(typically 1%). The external reference voltage should
be in the range from 1.26V to 5.5V and capable of
supplying 1mA.
Table 1. Sample Trim Resistance Values
V_OUT (V)
R_TD (kΩ)
R_TU (kΩ)
0.7
686.36, (V_REF = 5V)
1.0
1370, (V_REF = 5V)
1.25
8088, (V_REF = 5V)
1.3
------ None – factory default -----
1.5
690.95
2.5
114.68
3.3
68.78
6.5 Output Current Limit
When the output load exceeds the current limit
threshold, the converter will enter a low power hiccup
mode. Once the overcurrent is removed, the output
voltage will recover automatically.
6.6 Output Current Limit Adjustment
The OCP adjustment function allows greater flexibility
to set the output current limit inception point (I_LIM),
from default of 22A to a minimum of 14.8A using an
external resistor and a capacitor. To adjust the I_LIM,
place the resistor R_OCP between OCPA and OCPB
pins, and the capacitor C_OCP between OCPA and Vout
pins. Do not short OCPA directly to OCPB.
To calculate R_OCP and C_OCP, use the equations below:
R_OCP = 10(I_LIM -12.6) / (22.8 - I_LIM ), kΩ
C_OCP = 414.4/R_OCP - 26, nF,
where R_OCP is on kΩ
Table 2. Sample Standard Values for R_OCP and C_OCP
I_LIM
R_OCP
C_OCP
~22A
Open
None
~20A
26.7kΩ
None
~17A
7.5kΩ
27nF
~13.5A
1kΩ
390nF
6.7 Remote Voltage Sense
This feature provides improved load regulation by
compensating for the voltage drop between the output
of the converter and the load.
REV. 2.6 APR 07, 2005
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