AIC2951D-30CN Ver la hoja de datos (PDF) - Analog Intergrations
Número de pieza
componentes Descripción
Lista de partido
AIC2951D-30CN Datasheet PDF : 10 Pages
| |||
AIC2951/2951D
n BLOCK DIAGRAM
FB
7
3
SHDN
VIN
8
VOUT
1
2
+
- ERROR
AMP
RF1
6
60mV
+
+
RF2
+
5
-
ERROR DETECTION
COMPARATOR
1.235V REFERENCE
4
SENSE
TAP
ERROR
GND
n PIN DESCRIPTIONS
PIN 1: VOUT - Output pin.
PIN 2: SENSE -Remote sense input, connected
to internal resistor divider.
PIN 3: SHDN - Shutdown input.
PIN 4: GND - Power GND.
PIN 5: ERROR - Open drain output of error flag warns.
PIN 6: TAP - Center output of internal resistor di-
vider.
PIN 7: FB
- Error amplifier positive feedback (see
Block Diagram)
PIN 8: VIN - Power supply input
n APPLICATION INFORMATIONS
Output Filter Capacitors
A 1µF (or greater) capacitor is required between the AIC2951/AIC2951D output and ground for stability. Without
this capacitor the part will oscillate. Even though most types of capacitor may work, if Aluminum electrolytic type
is used, the equivalent series resistance (ESR) should be held to 5Ω or less. Many Aluminum electrolytics have
electrolytes that freeze at about -30°C, so solid tantalums are recommended for operation below -25°C. The value
of this capacitor may be increased without limit.
The output capacitance required for stability varies with output voltage (smaller for higher output voltage) and out-
put current (smaller for lower output currents). At the worst-case situation of a 150mA load at 1.235V output
(output shorted to FB pin) a 3.3 µF or greater capacitor should be used.
A 0.1µF capacitor should be placed from the AIC2951/2951D input to ground if the lead inductance between the
input and power source exceeds 500nH (approximately 10 inches of trace). Noise injection into the feedback
terminal of the AIC2951/2951D from nearby noise sources can also upset the output. This may especially
be a problem when using high value external resis-
tors to set the output voltage. Adding a 100pF ca-
pacitor between output and feedback and increas-
ing the output capacitor to at least 3.3µF will cure
this problem.
Programming the Output Voltage
The AIC2951/2951D series can be set to deliver
any output voltage from 1.235V to 11V by using an
external voltage divider. In addition, internal voltage
7
Share Link: 