rt8297a Richtek Technology Corporation, rt8297a Datasheet - Page 3

• Manufacturer Part Number: rt8297a
• Description: 1.5a, 17v, 340/800khz Synchronous Step-down Converter
• Manufacturer: Richtek Technology Corporation

Functional Pin Description
Function Block Diagram
DS8297A/B-00 March 2011
7, 8, 9 (Exposed Pad) GND
Pin No.
VIN
EN
FB
1
2
3
4
5
6
5k
2.5V
0.4V
0.8V
Comparator
SW
VIN
BOOT
EN
FB
PGOOD
1V
3V
Enable
Pin Name
+
-
Error Amp
OV Comparator
UV Comparator
+
-
+
-
+
-
35pF 400k
Regulator
Internal
1pF
V
Switch Node. Connect to external L-C filter.
Input Supply Voltage. Must bypass with a suitably large ceramic
capacitor.
Bootstrap for High Side Gate Driver. Connect 0.01μF or greater ceramic
capacitor from BOOT to SW pin.
Chip Enable. A logic-high enables the converter; a logic-low forces the
RT8297A/B into shutdown mode, reducing the supply current to less
than 5μA. Attach this pin to VIN with a 100kΩ pull up resistor for
automatic startup.
Feedback Input Pin. For an adjustable output, connect an external
resistive voltage divider to this pin.
Power Good Indicator. The output of this pin is low if the output voltage is
12.5% less than the nominal voltage. Otherwise, it is an open drain.
Ground. The exposed pad must be soldered to a large PCB and
connected to GND for maximum power dissipation.
A
V
CC
OV
UV
340kHz/800kHz
Foldback
Control
OSC
PGOOD
Slope Comp
+
-
PGOOD
Comparator
Current
Comparator
Pin Function
Current Sense
Amplifier
S
R
+
-
Q
Q
0.7V
FB
V
+
-
A
RT8297A/B
145m
140m
www.richtek.com
BOOT
SW
GND
3