MAX8860 Maxim, MAX8860 Datasheet - Page 8

• Manufacturer Part Number: MAX8860
• Description: Low-Dropout / 300mA Linear Regulator in MAX
• Manufacturer: Maxim

When operating the MAX8860 with an input voltage
above +5.5V, a minimum load current of 20µA is
required to maintain regulation in preset voltage mode.
When setting the output with external resistors, ensure
that the minimum current through the external feedback
resistors and load is at least 30µA. This applies only
when the input voltage exceeds +5.5V. For input volt-
ages less than +5.5V, the MAX8860 maintains regula-
tion and stability without external loading.
Typically, use a 2.2µF capacitor on the input and a
2.2µF capacitor on the output of the MAX8860.
Capacitor type is not critical, as long as it has an ESR
less than 0.5Ω. Larger capacitor values and lower ESR
provide better supply-noise rejection and transient
response. Use higher-value capacitors (10µF) if large,
fast input or load transients are anticipated or if the
device is located several inches from the power source.
For stable operation over the full temperature range,
with load currents up to 300mA, a minimum output-
capacitor value of 2.2µF is recommended. There is no
upper limit to capacitor size. The circuit used to gener-
ate the typical operating characteristics data used
2.2µF, X7R, 16V (1206) ceramic capacitors. These
capacitors typically have an ESR of 50mΩ.
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
© 1999 Maxim Integrated Products
Low-Dropout, 300mA
Linear Regulator in µMAX
_____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
Applications Information
V
IN
Capacitor Selection and
> +5.5V Minimum Load
Current Requirements
Regulator Stability
Printed USA
The MAX8860 is designed to deliver low dropout volt-
age and low quiescent current in battery-powered sys-
tems. Power-supply rejection is 67dB at low frequencies
and rolls off above 100kHz. At high frequencies, the out-
put capacitor is the major contributor to the rejection of
power-supply noise (see the Power-Supply Rejection
Ratio vs. Frequency graph in the Typical Operating
Characteristics).
When operating from sources other than batteries,
improve supply-noise rejection and transient response
by increasing the values of the input and output capaci-
tors, and by using passive filtering techniques (see the
supply and load-transient responses in the Typical
Operating Characteristics).
The MAX8860 load-transient response graph (see
Typical Operating Characteristics) shows the output
response due to changing load current. Reduce over-
shoot by increasing the output capacitor’s value and
decreasing its ESR.
A regulator’s minimum input-output voltage differential
(or dropout voltage) determines the lowest usable supply
voltage. In battery-powered systems, this determines the
useful end-of-life battery voltage. Because the MAX8860
uses a P-channel MOSFET pass transistor, its dropout
voltage is a function of R
plied by the load current (see Electrical Characteristics).
TRANSISTOR COUNT: 148
Power-Supply Rejection and Operation
is a registered trademark of Maxim Integrated Products.
from Sources Other than Batteries
Input-Output (Dropout) Voltage
Load-Transient Considerations
DS(ON)
Chip Information
(typically 0.5Ω) multi-