1 2 V o r Ad ju s t a b le , Hig h -Effic ie n c y,
Lo w I , S t e p -Up DC-DC Co n t ro lle r
Q
____________________________Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s (c o n t in u e d )
(Circuit of Figure 2a, T = +25°C, unless otherwise noted.)
A
ENTERING/EXITING SHUTDOWN
MAX71
A
B
0V
5V
0V
2ms/div
I
= 500mA, V = 5V
IN
OUT
A: SHDN, 5V/div
B: V , 5V/div
OUT
______________________________________________________________P in De s c rip t io n
PIN
NAME
FUNCTION
1
2
EXT
V+
Gate Drive for External N-Channel Power Transistor
Power-Supply Input. Also acts as a voltage-sense point when in bootstrapped mode.
Feedback Input for Adjustable-Output Operation. Connect to ground for fixed-output operation.
Use a resistor divider network to adjust the output voltage. See Setting the Output Voltage section.
3
4
5
FB
Active-High TTL/CMOS Logic-Level Shutdown Input. In shutdown mode, V
is a diode drop
OUT
below V+ (due to the DC path from V+ to the output) and the supply current drops to 5µA
maximum. Connect to ground for normal operation.
SHDN
REF
1.5V Reference Output that can source 100µA for external loads. Bypass to GND with 0.1µF.
The reference is disabled in shutdown.
6
7
AGND
GND
Analog Ground
High-Current Ground Return for the Output Driver
Positive Input to the Current-Sense Amplifier. Connect the current-sense resistor between CS
and GND.
8
CS
_______________________________________________________________________________________
6
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
