AN8049SH-E1 Panasonic - SSG, AN8049SH-E1 Datasheet - Page 19

• Manufacturer Part Number: AN8049SH-E1
• Description: IC MULTI CONFIG 40MA SSOP24D
• Manufacturer: Panasonic - SSG
• Type: Step-Down (Buck), Step-Up (Boost), Invertingr

Specifications of AN8049SH-E1

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 3
• Current - Output: 40mA
• Frequency - Switching: 20kHz ~ 1MHz
• Voltage - Input: 1.8 ~ 14 V
• Operating Temperature: -30°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 24-SSOP
• Power - Output: 146mW
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Voltage - Output: -
• Other names: AN8049SHE1; AN8049SHE1TR

I Application Notes (continued)
[6] Setting the maximum duty
[7] Setting the soft start time
range 0% to 100% by adding an external resistor.
1. To use a duty lower than the current duty (80% to 92%)
2. To use a duty higher than the current duty (80% to 92%)
The maximum duty is set to 86% internally to the IC. However, this setting can be changed to be any value in the
characteristics in the "[2] Main characteristics" section and determine the value of the external resistor R
formula A.
to-sample variations of the internal resistors R1 and R2. (However, the direction of the sample-to-sample varia-
tions is identical for R1 and R2.) Determine the size of the sample-to-sample variations in the DT pin voltage V
from formula B, and estimate the size of the sample-to-sample variation in the duty from the provided DT pin
voltage vs. maximum on-duty characteristics in the "[2] Main characteristics" section .
variations in the same manner as in item 1 above.
The soft start time is determined by the value of the capacitor connected between the DT pin and ground.
Use the following formula to set the soft start time t
t
D
Insert the resistor R
Determine the DT pin voltage for the required duty from the provided DT pin voltage vs. maximum on-duty
Note that there is a sample-to-sample variation of −19% to +33% due to temperature characteristics and sample-
R
V
Insert the resistor R
Use formulas C and D to determine the value of the external resistor R
R
V
= − R
DT
DT
DT
DT
=
=
=
=
2
V
(
R
R
× C
R
REF
R
1
2
1
1
R
+ R
1
+ R
DT
2
+
− (
R
/ R
R
2
1
× ln (1 −
1
2
V
/ R
/ R
Soft start time, t
2
R
DT
1
REF
) × V
V
1
DT
DT
+
DT
DT
DT
− V
R
1
DT
× V
× V
between the DT pin and the V
between the DT pin and ground.
2
V
) × V
DT
−
REF
REF
REF
V
V
R
DT
REF
DT
− V
1
D
DT
×
··········A
··········B
··········C
··········D
R
R
1
2
OSC pin waveform
)
SDH00012BEB
D
.
R1
R2
REF
R1
R2
R1
R2
pin.
DT pin waveform
V
1.26 V
DT
DT
V
1.26 V
REF
DT
V
1.26 V
REF
R
REF
DT
R
V
0.2 V
C
DT
DT
DT
DT
and the size of the sample-to-sample
R1
R2
R1
R2
ch.1, 2
ch.1, 2
45 kΩ
55 kΩ
45 kΩ
55 kΩ
AN8049SH
44 kΩ
56 kΩ
44 kΩ
56 kΩ
DT
ch.3
ch.3
from
19
DT