AAT1143IJS-0.6-T1 AnalogicTech, AAT1143IJS-0.6-T1 Datasheet - Page 12

• Manufacturer Part Number: AAT1143IJS-0.6-T1
• Description: 1MHz 400mA Step-Down Converter
• Manufacturer: AnalogicTech

Adjustable Output Resistor Selection
For applications requiring an adjustable output voltage,
the 0.6V version can be externally programmed. Resistors
R1 and R2 of Figure 5 program the output to regulate at
a voltage higher than 0.6V. To limit the bias current
required for the external feedback resistor string while
maintaining good noise immunity, the minimum sug-
gested value for R2 is 59kΩ. Although a larger value will
further reduce quiescent current, it will also increase the
impedance of the feedback node, making it more sensi-
tive to external noise and interference. Table 2 summa-
rizes the resistor values for various output voltages with
12
SwitchReg
Figure 2: AAT1143 Evaluation Board
TM
Top Side.
Figure 4: AAT1143 Evaluation Board
w w w . a n a l o g i c t e c h . c o m
Bottom Side.
R2 set to either 59kΩ for good noise immunity or 221kΩ
for reduced no load input current.
The adjustable version of the AAT1143, combined with
an external feedforward capacitor (C4 in Figure 1),
delivers enhanced transient response for extreme pulsed
load applications. The addition of the feedforward
capacitor typically requires a larger output capacitor C1
for stability.
R1 =
1MHz 400mA Step-Down Converter
Figure 3: Exploded View of Evaluation
⎛
⎝
V
V
OUT
REF
Board Top Side Layout.
-1 · R2 =
⎞
⎠
PRODUCT DATASHEET
⎛
⎝
1.5V
0.6V
AAT1143
- 1 · 59kΩ = 88.5kΩ
⎞
⎠
1143.2009.02.1.11