Datasheet
MAX15035
15A Step-Down Regulator with Internal Switches
10 ______________________________________________________________________________________
Pin Description
PIN NAME FUNCTION
1, 17, 27, 31,
39, 40
N.C. No Connection. Not internally connected.
2EN
Shutdown Control Input. Connect to V
DD
for normal operation. Pull EN low to put the controller into its
2μA (max) shutdown state. The MAX15035 slowly ramps down the target/output voltage to ground
and after the target voltage reaches 0.1V, the controller forces LX into a high-impedance state and
enters the low-power shutdown state. Toggle EN to clear the fault-protection latch.
3, 28 AGND Analog Ground. Internally connected to EP1.
4V
DD
Supply Voltage Input for the DL Gate Driver. Connect to the system supply voltage (+4.5V to +5.5V).
Bypass V
DD
to power ground with a 1μF or greater ceramic capacitor.
5, 16 LX
Inductor Connection. Internally connected to EP2. Connect LX to the switched side of the inductor as
shown in Figure 1.
6–15 PGND Power Ground
18–26 IN Power MOSFET Input Power Source. Internally connected to EP3.
29 TON
Switching Frequency-Setting Input. An external resistor between the input power source and TON
sets the switching period (t
SW
= 1/f
SW
) according to the following equation:
where C
TON
= 16.26pF and V
FB
= V
REFIN
under normal operating conditions. If the TON current
drops below 10μA, the MAX15035 shuts down and enters a high-impedance state. TON is high
impedance in shutdown.
30 BST
Boost Flying Capacitor Connection. Connect to an external 0.1μF capacitor as shown in Figure 1. The
MAX15035 contains an internal boost switch/diode (Figure 2).
tCR k
V
V
SW TON TON
FB
OUT
=+
()
⎛
⎝
⎜
⎞
⎠
⎟
65. Ω
DYNAMIC OUTPUT-VOLTAGE TRANSITION
(PWM MODE)
MAX15035 toc28
40µs/div
C. INDUCTOR CURRENT,
10A/div
D. LX, 10V/div
-6A
0
1.5V
1.5V
1.05V
1.05V
12V
0
A
B
C
D
A. REFIN, 500mV/div
B. V
OUT
, 200mV/div
I
OUT
= 2A
DYNAMIC OUTPUT-VOLTAGE TRANSITION
(SKIP MODE)
MAX15035 toc29
40µs/div
C. INDUCTOR CURRENT,
10A/div
D. LX, 10V/div
10A
0
1.5V
1.5V
1.05V
1.05V
12V
0
A
B
C
D
A. REFIN, 500mV/div
B. V
OUT
, 200mV/div
I
OUT
= 2A
Typical Operating Characteristics (continued)
(MAX15035 Circuit of Figure 1, V
IN
= 12V, V
DD
= 5V, SKIP = GND, R
TON
= 200kΩ, T
A
= +25°C, unless otherwise noted.)