MAX767 Maxim, MAX767 Datasheet - Page 5

• Manufacturer Part Number: MAX767
• Description: 5V-to-3.3V / Synchronous / Step-Down Power-Supply Controller
• Manufacturer: Maxim

Figure 1. Standard Application Circuit
______________________________________________________________Pin Description
10, 14, 15
4–7, 11
PIN
12
13
16
17
18
19
20
1
2
3
8
9
NAME
PGND
SYNC
GND
N.C.
REF
V
BST
ON
DH
CS
DL
SS
LX
FB
CC
_______________________________________________________________________________________
Current-sense input: +100mV = nominal current-limit level referred to FB.
Soft-start input. Ramp time to full current limit is 1ms/nF of capacitance to GND.
ON/O
Low-current analog ground. Feedback reference point for the output.
3.3V internal reference output. Bypass to GND with 0.22µF minimum capacitor.
Oscillator control/synchronization input. Connect to V
300kHz. For external clock synchronization in the 240kHz to 350kHz range, a high-to-low transition
causes a new cycle to start.
Supply voltage input: 4.5V to 5.5V
No internal connection
Power ground
Gate-drive output for the low-side synchronous rectifier MOSFET
Boost capacitor connection (0.1µF)
Inductor connection. Can swing 2V below GND without latchup.
Gate-drive output for the high-side MOSFET
Feedback and current-sense input for the PWM
(OPTIONAL)
SHUTDOWN
5V-to-3.3V, Synchronous, Step-Down
0.22 F
—
ON/OFF
—
F
–
F
C6
C5
control input to disable the PWM. Tie directly to V
0.01 F
4.7 F
C4
ON
SS
SYNC
REF
MAX767
V CC
GND
PGND
10
R2
BST
DH
CS
DL
FB
Power-Supply Controller
LX
FUNCTION
N1
N2
D1
SMALL-
SIGNAL
SCHOTTKY
C3
0.1 F
CC
D2
or GND for 200kHz; connect to REF for
L1
CC
for automatic start-up.
4.5V TO 5.5V
C1
INPUT
R1
OUTPUT
3.3V
C2
5