SS6578 ETC-unknow, SS6578 Datasheet - Page 5

• Manufacturer Part Number: SS6578
• Description: High Efficiency Step Down Dc/dc Controller
• Manufacturer: ETC-unknow

Rev.2.02 4/06/2004
BLOCK DIAGRAM
PIN DESCRIPTIONS
PIN 1: VIN
PIN 2: DUTY - Duty cycle adjustment pin. To be
PIN 3: SHDN - Logical input to shutdown the
PIN 4: FB
- Input supply voltage - a range of
- Feedback comparator input, to
4V to 18V is recommended.
tied to the VIN pin directly or
through a resistor R
oscillator duty cycle. R
be over 1M
See TYPICAL PERFORMANCE
CHARACTERISTICS.
chip:
operation.
This pin should not be floating or
be forced to over 15V. In
shutdown mode DRI pin is held
high.
compare the feedback voltage
with the internal reference voltage.
V
V
SHDN
SHDN
SHDN
DUTY
VIN
= Low for shutdown.
FB
=
High
2
3
4
1
if V
IN
=20V.
DUTY
for
www.SiliconStandard.com
PFM
OSC
DUTY
to adjust
normal
+
-
must
Error
Comparator
LATCH
Reference
Voltage
Current Limit Comparator
1.22V
PIN 5: GND - Power ground.
PIN 6: DRI
PIN 7: CS-
PIN 8: CS+ - Current
Output
Driver
+
-
70mV
VIN
- Push-pull driver output to drive an
- Current-sense
should not exceed V
Connecting a resistor R1 to
converter output node and a
resistor R2 to ground yields the
output voltage:
V
external P-channel MOSFET or
PNP transistor. When driving a
PNP bipolar transistor, a base
resistor and a capacitor to the
base of PNP are recommended.
inverting input. This pin voltage
should go over 2V but should
not exceed VIN voltage.
non-inverting
voltage should go over 2V but
8
7
6
5
OUT
CS+
CS-
GND
DRI
=1.22 x (R1+R2)/ R2
sense
input. This pin
comparator
IN
comparator
voltage.
SS6578
5 of 11