MAX1589_07 Datasheet, PDF (8/12 Pages) Maxim Integrated Products – Low-Input-Voltage, 500mA LDO Regulator with RESETin SOT and TDFN

Low-Input-Voltage, 500mA LDO Regulator
with RESET in SOT and TDFN
MAXIMUM OUTPUT CURRENT
vs. INPUT VOLTAGE
(POWER DISSIPATION LIMIT)
600
T_A = +85°C
T_A = +70°C
500
400
300
200
100
MAXIMUM RECOMMENDED
OUTPUT CURRENT 6-PIN SOT23
0
0 0.5 1.0 1.5 2.0 2.5 3.0
(V_IN - V_OUT) (V)
Figure 2. Power Operating Regions for 6-Pin SOT23: Maximum
Output Current vs. Input Voltage
MAXIMUM OUTPUT CURRENT
vs. INPUT VOLTAGE
(POWER DISSIPATION LIMIT)
600
T_A = +85°C
500
400
300
200
100
MAXIMUM RECOMMENDED
OUTPUT CURRENT 6-PIN TDFN
0
0 0.5 1.0 1.5 2.0 2.5 3.0
(V_IN - V_OUT) (V)
Figure 3. Power Operating Region for 6-Pin TDFN: Maximum
Output Current vs. Input Voltage
capacitors to reduce noise and improve load-transient
response, stability, and power-supply rejection.
The output capacitor’s equivalent series resistance
(ESR) affects stability and output noise. Use output
capacitors with an ESR of 30mΩ or less to ensure sta-
bility and optimize transient response. Surface-mount
ceramic capacitors have very low ESR and are com-
monly available in values up to 10µF. Connect C_IN and
C_OUT as close to the MAX1589 as possible to minimize
the impact of PC board trace inductance.
Noise, PSRR, and Transient Response
The MAX1589 is designed to operate with low dropout
voltages and low quiescent currents in battery-powered
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) vs. 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.
The MAX1589 load-transient response (see the Typical
Operating Characteristics) shows two components of
the output response: a near-zero DC shift from the out-
put impedance due to the load-current change, and the
transient response. A typical transient response for a
step change in the load current from 100mA to 500mA
is 35mV. Increasing the output capacitor’s value and
decreasing the ESR attenuates the overshoot.
Input-Output (Dropout) Voltage
A regulator’s minimum input-output voltage difference
(dropout voltage) determines the lowest usable supply
voltage. In battery-powered systems, this determines
the useful end-of-life battery voltage. Because the
MAX1589 uses a P-channel MOSFET pass transistor, its
dropout voltage is a function of drain-to-source on-resis-
tance (R_DS(ON) = 0.33Ω) multiplied by the load current
(see the Typical Operating Characteristics):
V_DROPOUT = V_IN - V_OUT = 0.33Ω ✕ I_OUT
The MAX1589 ground current reduces to 70µA in dropout.
Chip Information
TRANSISTOR COUNT: 2556
PROCESS: BiCMOS
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