MAX15029ATB+T Maxim Integrated Products, MAX15029ATB+T Datasheet - Page 8

• Manufacturer Part Number: MAX15029ATB+T
• Description: IC REG LDO ADJ 500MA 10-TDFN
• Manufacturer: Maxim Integrated Products

Specifications of MAX15029ATB+T

• Regulator Topology: Positive Adjustable
• Voltage - Output: 0.5 ~ 3.3 V
• Voltage - Input: 1.43 ~ 3.6 V
• Voltage - Dropout (typical): 0.04V @ 500mA
• Number Of Regulators: 1
• Current - Output: 500mA
• Current - Limit (min): 700mA
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 10-TDFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The MAX15029/MAX15030 feature a 75mΩ (typ)
p-channel MOSFET pass transistor. Unlike similar
designs using pnp pass transistors, p-channel
MOSFETs require no base drive, reducing quiescent
current. pnp-based regulators also waste considerable
current in dropout when the pass transistor saturates
and uses high base-drive currents under large loads.
The MAX15029/MAX15030 do not suffer from these
problems and consume only 315µA (typ) of quiescent
current under heavy loads, as well as in dropout.
The MAX15029/MAX15030 are fully protected from a
short circuit at the output through current-limiting and
thermal-overload circuitry. In the fault condition when
the output is shorted to ground, the output current is
limited to a maximum of 1A. Under these conditions,
the device quickly heats up. When the junction temper-
ature reaches +165°C (typ), the thermal-overload cir-
cuitry turns off the output, allowing the part to cool
down. When the junction temperature cools to +150°C
(typ), the output turns back on and reestablishes regu-
lation. Current limiting and thermal protection continue
until the fault is removed. For continuous operation, do
not exceed the absolute maximum junction-tempera-
ture rating of T
The MAX15029/MAX15030 feature a soft-start function
that slowly ramps up the output voltage of the regulator
based on the value of the capacitor (C
from SS to GND. Upon power-up, C
a 5µA (typ) current source through SS. The voltage at
SS is compared to the internal 0.5V reference (V
The feedback voltage for regulation (V
of V
(V
rises above V
reference voltage since it is the lower of V
The value of C
time, t
where C
1.425V to 3.6V Input, 500mA Low-Dropout
Regulators with BIAS Input
8
REG
_______________________________________________________________________________________
SS
SS
) rises at the same rate. Once V
or V
SS
. Use the following formula to determine C
Internal p-Channel Pass Transistor
is in farads and t
REF
REF
J
SS
. As V
= +150°C.
, the regulation voltage then tracks the
determines the length of the soft-start
C
SS
SS
Thermal Fault Protection
= 10
rises, the regulation voltage
SS
-5
is in seconds.
x t
SS
SS
Short-Circuit/
REG
SS
is charged with
SS
SS
) is the lower
reaches and
Soft-Start
) connected
and V
SS
REF
REF
.
).
.
The MAX15029/MAX15030 include an enable input. To
shut down the IC, drive EN low. In shutdown mode, the
current drawn by BIAS is less than 2µA. This feature is
extremely useful in an automotive application where the
BIAS input is derived from an always-on LDO expecting
to provide minimal dark current. For normal operation,
drive EN high or connect EN to IN for continuous on
operation. During shutdown, an internal 10kΩ resistor is
connected between OUT and GND.
The MAX15029/MAX15030 feature an adjustable output
voltage from 0.5V to V
connected as a voltage-divider to FB as shown in
Figure 1. The output voltage is set by the following
equation:
where typically V
to optimize load-transient response for no load to full
load transients, use the resistor-divider as a minimum
load and choose R2 to be 500Ω. To simplify resistor
selection:
Figure 1. MAX15030 Typical Application Circuit
1.425V TO 3.6V
SHUTDOWN
ALWAYS-ON
3V TO 5.5V
ENABLE
INPUT
INPUT
1μF
Programming the Output Voltage
Applications Information
FB
V
R
EN
BIAS
IN
OUT
1
= 0.5V. Choose R2 to be 10kΩ. Or,
=
R
MAX15030
=
IN
2
V
⎛
⎜
⎝
SS
using two external resistors
FB
V
V
OUT
0.1uF
FB
⎛
⎝ ⎜
1
+
OUT
GND
−
R
I.C.
R
FB
Shutdown Mode
1
1
2
⎞
⎟
⎠
⎞
⎠ ⎟
R1
R2
OUTPUT
2.2μF