AS1322_1 AMSCO [austriamicrosystems AG], AS1322_1 Datasheet - Page 2

• Manufacturer Part Number: AS1322_1
• Description: Low Voltage, Micropower, DC-DC Step-Up Converters
• Manufacturer: AMSCO [austriamicrosystems AG]

AS1322
Data Sheet
4 Pin Assignments
Figure 2. Pin Assignments (Top View)
Pin Descriptions
Table 2. Pin Descriptions
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SHDNN
Name
V
GND
Pin
SW
V
FB
OUT
- P i n A s s i g n m e n t s
IN
Number
Pin
1
2
3
4
5
6
Switch Pin. Connect an inductor between this pin and V
trace lengths as short and wide as is practical to reduce EMI and voltage
overshoot. If the inductor current falls to zero, or pin SHDNN is low, an
internal 100Ω anti-ringing switch is connected from this pin to V
minimize EMI.
Note: An optional Schottky diode can be connected between this pin and
V
Signal and Power Ground. Provide a short, direct PCB path between this
pin and the negative side of the output capacitor(s).
Feedback Pin. Feedback input to the g
divider tap to this pin. The output voltage can be adjusted from 2.5 to 5V by:
V
Shutdown Pin. Logic controlled shutdown input.
1 = Normal operation, 1.2MHz typical operating frequency.
0 = Shutdown; quiescent current <1µA. If SHDNN is undefined, pin SW may
ring.
Note: In a typical application, SHDNN should be connected to V
1MΩ pull-up resistor.
Output Voltage Sense Input and Drain of the Internal PMOS
Synchronous Rectifier. Bias is derived from V
PCB trace length from V
short and wide as is practical. V
during shutdown.
Input Voltage. The AS1322 gets its start-up bias from V
exceeds V
started, operation is completely independent from V
limited by the output power level and the internal series resistance of the
supply.
OUT
OUT
GND
SW
FB
.
= 1.23V[1 + (R
1
2
3
IN
Revision 1.07
AS1322
, in which case the bias is derived from V
1
/R
2
OUT
)]
6 V
5 V
4 SHDNN
to the output filter capacitor(s) should be as
IN
OUT
Description
OUT
is held at approximately V
m
error amplifier. Connect a resistor
OUT
when V
IN
OUT
. Operation is only
IN
IN
. Thus, once
. Keep the PCB
OUT
unless V
IN
exceeds V
IN
IN
- 0.6V
to
through a
OUT
2 - 17
IN
.