ST LDS3985M125R, LDS3985PM12R, LDS3985M135R, LDS3985M15R, LDS3985M18R User Manual

LDS3985xx

Ultra low drop-low noise BiCMOS 300 mA voltage regulator for use with very low ESR output capacitor

Features

■Input voltage from 2.5 V to 6 V

■Stable with low ESR ceramic capacitors

■Ultra low dropout voltage (150 mV typ. at 300 mA load, 0.4 mV typ. at 1 mA load)

■Very low quiescent current (85 µA typ. at no load, 200 µA typ. at 300 mA load; max 1.5 µA in off mode)

■Guaranteed output current up to 300 mA

■Wide range of output voltage:

–from 1.25 V to 5.0 V

■Fast turn-on time: typ. 240 µs

–[CO = 2.2 µF, CBYP = 33 nF and IO = 1 mA]

■Logic-controlled electronic shutdown

■Internal current and thermal limit

■Output low noise voltage 30 µVRMS over 10 Hz to 100 kHz

■SVR of 55 dB at 1 kHz, 50 dB at 10 kHz

■Temperature range: - 40 °C to 125 °C

Description

The LDS3985xx provides up to 300 mA, from 2.5 V to 6 V input voltage. It is stable with ceramic and high quality tantalum capacitor. The ultra low drop voltage, low quiescent current and low noise

DFN6						SOT23-5L

makes it suitable for low power applications and in battery powered systems. Regulator ground current increases only slightly in dropout, further prolonging the battery life. Shutdown logic control function is available, this means that when the device is used as local regulator, it is possible to put a part of the board in standby, decreasing the total power consumption. Typical applications are in mobile phone and similar battery powered wireless systems, portable information appliances.

Table 1.	Device summary
	Part numbers		Output voltages
	LDS3985XX15		1.5 V
	LDS3985XX18		1.8 V
	LDS3985XX25		2.5 V
	LDS3985XX28		2.8 V
	LDS3985XX30		3.0 V
	LDS3985XX33		3.3 V
	LDS3985XX50		5.0 V
July 2010	Doc ID 11039 Rev 7		1/20
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Contents	LDS3985xx

Contents

1	Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. 3
2	Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4
3	Typical application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	5
4	Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	6
5	Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	7
6	Typical performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . .	9
7	Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	12
8	Order codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	18
9	Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	19

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LDS3985xx	Diagram

1 Diagram

Figure 1. Schematic diagram

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Pin configuration	LDS3985xx

2 Pin configuration

Figure 2. Pin connections (top view for SOT23-5L, top through view for DFN6)

SOT23-5L

DFN6

Table 2.

Pin description

Pin n° for

Pin n° for

Symbol

Name and function

SOT23-5L

DFN6

1

1

VI

Input voltage of the LDO

2

5

GND

Common ground

3

6

VINH

Inhibit input voltage: on mode when VINH ≥ 1.2 V, off mode when VINH ≤

0.4 V (Do not leave floating, not internally pulled down/up)

4

4

BYPASS

Bypass pin: connect an external capacitor (usually 10 nF) to minimize

noise voltage

5

3

VO

Output voltage of the LDO

-

2

N.C.

Not connect

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LDS3985xx	Typical application

3 Typical application

Figure 3. Typical application circuit

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Maximum ratings				LDS3985xx
4	Maximum ratings
Table 3.	Absolute maximum ratings
Symbol		Parameter	Value		Unit
VI		DC input voltage	-0.3 to 6 (1)		V
VO		DC output voltage	-0.3 to VI+0.3		V
VINH		INHIBIT input voltage	-0.3 to VI+0.3		V
IO		Output current	Internally limited
PD		Power dissipation	Internally limited
TSTG		Storage temperature range	-65 to 150		°C
TOP		Operating junction temperature range	-40 to 125		°C

1. The input pin is able to withstand non repetitive spike of 6.5 V for 200 ms.

Note:	Absolute maximum ratings are those values beyond which damage to the device may occur.
	Functional operation under these condition is not implied.
Table 4.	Thermal data
Symbol	Parameter	SOT23-5L	DFN6	Unit
RthJC	Thermal resistance junction-case	81	10	°C/W
RthJA	Thermal resistance junction-ambient	255	55	°C/W

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