MAX879L Maxim Integrated Products, MAX879L Datasheet - Page 6

• Manufacturer Part Number: MAX879L
• Description: (MAX877L - MAX879L) Step-Up & Down DC-DC Converters
• Manufacturer: Maxim Integrated Products

Low-Voltage Input, 3V/3.3V/5V/
Adjustable Output, Step-Up DC-DC Converters
(Circuit of Figure 1, T
6
_____________________________Typical Operating Characteristics (continued)
______________________________________________________________Pin Description
PIN
_______________________________________________________________________________________
1
2
3
4
5
6
7
8
(MAX777L)
(MAX778L)
(MAX779L)
NAME
AGND
PGND
SHDN
OUT
N.C.
ILIM
SEL
FB
LX
IN
A
= +25°C, unless otherwise noted.)
Sets switch current-limit input. Connect to IN for 1A current limit. A resistor from ILIM to IN sets lower
peak inductor currents.
Input from battery
Analog ground. Not internally connected to PGND.
Power ground. Must be low impedance; solder directly to ground plane or star ground. Connect to
AGND, close to the device.
Collector of 1A NPN power switch and emitter of Active Rectifier PNP.
Voltage output. Connect filter capacitor close to pin.
Shutdown input disables power supply when low. Also disconnects load from input. Threshold is set at
V
No connect—not internally connected.
Selects the main output voltage. 3.3V when hard-wired to AGND, 3.0V when left open.
Feedback input for adjustable-output operation. Connect to an external voltage divider between V
and AGND.
IN
/2.
A: SHDN, 2V/div
B: V
V
OUT
OUT
= 3V
, 1V/div
START-UP TIME
MAX778L
10ms/div
FUNCTION
B
A
OUT