LP5952_15 Datasheet, PDF (12/22 Pages) Texas Instruments – 350mA Dual Rail Linear Regulator

LP5952
SNVS469E – OCTOBER 2006 – REVISED MAY 2013
www.ti.com
Figure 19 shows the output current derating due to these considerations:
400
350
300
250
Micro SMD
200
150
100
LLP
50
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
V_IN ± V_OUT / V
Figure 19. Maximum Load Current vs V_IN - V_OUT, T_A = 85°C, V_OUT = 1.5V, θ_JA(DSBGA) = 95°C/W,
θ_JA(USON) = 150°C/W,
The typical contribution of the bias input voltage supply V_BATT to the power dissipation can be neglected:
P_{D_VBATT} = V_BATT * I_QVBATT = 5.5V * 50µA = 0.275mW typical.
(4)
EXTERNAL CAPACITORS
As is common with most regulators, the LP5952 requires external capacitors to ensure stable operation. The
LP5952 is specifically designed for portable applications requiring minimum board space and the smallest size
components. These capacitors must be correctly selected for good performance.
INPUT CAPACITOR
If the LP5952 is used stand alone, an input capacitor at V_IN is required for stability. It is recommended that a
1.0µF capacitor be connected between the LP5952 power voltage input pin V_IN and ground (this capacitance
value may be increased without limit).
This capacitor must be located a distance of not more than 1 cm from the V_IN pin and returned to a clean
analogue ground. Any good quality ceramic, tantalum, or film capacitor may be used at the input.
A capacitor at V_BATT is not required if the distance to the supply does not exceed 5cm.
If the device is used in the typical application as post regulator after a DC-DC regulator, no input capacitors are
required at all as the capacitors of the DC-DC regulator (C_IN and C_OUT) are sufficient if both components are
mounted close to each other and a proper GND plane is used. If the distance between the output capacitor of the
DC-DC regulator and the V_IN pin of the LP5952 is larger than 5cm, it's recommended to add the mentioned input
capacitor at V_IN.
Important: Tantalum capacitors can suffer catastrophic failures due to surge current when connected to a low-
impedance source of power (like a battery or a very large capacitor). If a tantalum capacitor is used at the input,
it must be ensured by the manufacturer to have a surge current rating sufficient for the application.
The ESR (Equivalent Series Resistance) of the input capacitor should be in the range of 3mΩ to 300mΩ. The
tolerance and temperature coefficient must be considered when selecting the capacitor to ensure the
capacitance will remain ≥ 470nF over the entire operating temperature range.
OUTPUT CAPACITOR
The LP5952 is designed specifically to work with very small ceramic output capacitors. A ceramic capacitor
(dielectric types X7R, Z5U, or Y5V) in the 2.2µF range (up to 10µF) and with an ESR between 3mΩ to 300mΩ is
suitable as C_OUT in the LP5952 application circuit.
This capacitor must be located a distance of not more than 1cm from the V_OUT pin and returned to a clean
analogue ground.
12
Submit Documentation Feedback
Product Folder Links: LP5952
Copyright © 2006–2013, Texas Instruments Incorporated