Datasheet MAX1818 (Maxim) - 8

filename ../../../../../GANGU/2018/WORK/CONVERSIONS/COMPLETED/MAX4888B-888C DS/MAX4888B DS.pdf MAX1818 500mA Low-Dropout Linear Regulator in SOT23
Applications Information
The MAX1818 load-transient response (see Typical
Capacitor Selection and
Operating Characteristics) shows two components of
Regulator Stability
the output response: a DC shift from the output imped- ance due to the load current change, and the transient Capacitors are required at the MAX1818’s input and out- response. A typical transient response for a step change put for stable operation over the full temperature range in the load current from 100mA to 500mA is 8mV. and with load currents up to 500mA. Connect a 1μF Increasing the output capacitor’s value and decreasing capacitor between IN and ground and a 3.3μF low-ESR the ESR attenuates the overshoot. capacitor between OUT and ground. For output voltages less than 2V, use a 4.7μF low-ESR output capacitor. The
Input-Output (Dropout) Voltage
input capacitor (CIN) lowers the source impedance of the A regulator’s minimum input-to-output voltage differential input supply. Reduce noise and improve load-transient (dropout voltage) determines the lowest usable supply response, stability, and powersupply rejection by using voltage. In battery-powered systems, this determines the larger output capacitors, such as 10μF. useful end-of-life battery voltage. Because the MAX1818 The output capacitor’s (C uses a P-channel MOSFET pass transistor, its dropout OUT) equivalent series resis- tance (ESR) affects stability and output noise. Use output voltage is a function of drain-to-source on-resistance capacitors with an ESR of 0.1Ω or less to ensure stability (RDS(ON)) multiplied by the load current (see Typical and optimum transient response. Surfacemount ceramic Operating Characteristics). capacitors have very low ESR and are commonly avail- VDROPOUT = VIN - VOUT = RDS(ON) x IOUT able in values up to 10μF. Connect CIN and COUT as close to the MAX1818 as possible to minimize the impact The MAX1818 ground current remains below 150μA in of PC board trace inductance. dropout.
Noise, PSRR, and Transient Response
The MAX1818 is designed to operate with low dropout
Chip Information
voltages and low quiescent currents in battery-powered TRANSISTOR COUNT: 845 systems while still maintaining good noise, transient response, and AC rejection. See the Typical Operating Characteristics for a plot of power-supply rejection ratio (PSRR) versus frequency. When operating from noisy sources, improved supply-noise rejection and transient response can be achieved by increasing the values of the input and output bypass capacitors and through passive filtering techniques.
Selector Guide Package Information
For the latest package outline information and land patterns
PART AND SOT23 SOT23 TOP
(footprints), go to
www.maximintegrated.com/packages
. Note
SUFFIX VOUT TOP MARK (RoHS MARK COMPLIANT)
that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but MAX1818EUT15 1.5V or Adj AASO ABZM the drawing pertains to the package regardless of RoHS status. MAX1818EUT18 1.8V or Adj AANU ABZG
PACKAGE TYPE PACKAGE CODE OUTLINE NO.
MAX1818EUT20 2.0V or Adj AANV ABZJ 6 SOT23 U6F-6
21-00 58
MAX1818EUT25 2.5V or Adj AANF ABZK 6 SOT23# U6FH-6
21-00 58
MAX1818EUT33 3.3V or Adj AANG ABZH MAX1818EUT50 5.0V or Adj AANH ABZL www.maximintegrated.com Maxim Integrated │ 8