MAX1589AETT250-T Datasheet, PDF (8/12 Pages) Maxim Integrated Products – Low-Input-Voltage, 500mA LDO Regulator with RESET in 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 MAX1589A as possible to mini-
mize the impact of PC board trace inductance.
Noise, PSRR, and Transient Response
The MAX1589A 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 MAX1589A load-transient response (see the
Typical Operating Characteristics) shows two compo-
nents of the output response: a near-zero DC shift from
the output 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
MAX1589A 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 MAX1589A ground current reduces to 70µA in
dropout.
Chip Information
TRANSISTOR COUNT: 2556
PROCESS: BiCMOS
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