MAX8868 MAXIM [Maxim Integrated Products], MAX8868 Datasheet - Page 8

• Manufacturer Part Number: MAX8868
• Description: Low-Noise, Low-Dropout, 150mA Linear Regulators in SOT23
• Manufacturer: MAXIM [Maxim Integrated Products]

ESR variation with temperature. With dielectrics such as
Z5U and Y5V, it may be necessary to use 2.2µF or
more to ensure stability at temperatures below -10°C.
With X7R or X5R dielectrics, 1µF should be sufficient at
all operating temperatures. Also, for high-ESR tantalum
capacitors, 2.2µF or more may be needed to maintain
ESR in the stable region. A graph of the Region of
Stable C
Typical Operating Characteristics .
Use a 0.01µF bypass capacitor at BP for low output volt-
age noise. Increasing the capacitance will slightly
decrease the output noise, but increase the start-up time.
Values above 0.1µF provide no performance advantage
and are not recommended (see Shutdown Exit Delay
graph in the Typical Operating Characteristics ).
The MAX8867/MAX8868 are designed to deliver low
dropout voltages and low quiescent currents in battery-
powered systems. Power-supply rejection is 63dB at
low frequencies and rolls off above 10kHz. See the
Power-Supply Rejection Ratio Frequency graph in the
Typical Operating Characteristics .
Low-Noise, Low-Dropout,
150mA Linear Regulators in SOT23
TRANSISTOR COUNT: 247
SUBSTRATE CONNECTED TO GND
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
8
© 1998 Maxim Integrated Products
________________________________________________________Package Information
___________________Chip Information
_____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
OUT
ESR vs. Load Current is shown in the
Sources Other than Batteries
PSRR and Operation from
Printed USA
When operating from sources other than batteries,
improved supply-noise rejection and transient response
can be achieved by increasing the values of the input
and output bypass capacitors, and through passive filter-
ing techniques. The Typical Operating Characteristics
show the MAX8867/MAX8868’s line- and load-transient
responses.
The MAX8867/MAX8868 load-transient response
graphs (see Typical Operating Characteristics ) show
two components of the output response: a DC shift
from the output impedance due to the load current
change, and the transient response. A typical transient
for a step change in the load current from 0mA to 50mA
is 12mV. Increasing the output capacitor’s value and
decreasing the ESR attenuates the overshoot.
A regulator’s minimum input-output voltage differential
(or dropout voltage) determines the lowest usable sup-
ply voltage. In battery-powered systems, this will deter-
mine the useful end-of-life battery voltage. Because the
MAX8867/MAX8868 use a P-channel MOSFET pass
transistor, their dropout voltage is a function of drain-to-
source on-resistance (R
current (see Typical Operating Characteristics ).
is a registered trademark of Maxim Integrated Products.
Input-Output (Dropout) Voltage
Load-Transient Considerations
DS(ON)
) multiplied by the load