ST LD1085D2T18R, LD1085DT18R, LD1085V25, LD1085DT25R, LD1085DT33R User Manual

LD1085xx

3 A low drop positive voltage regulator adjustable and fixed

Features

■Typical dropout 1.3 V (at 3 A)

■Three terminal adjustable or fixed output voltage 1.5 V, 1.8 V, 2.5 V, 3.3 V, 5 V, 12 V.

■Automotive Grade product: adjustable VOUT only in TO-220 Full Pack package

■Guaranteed output current up to 3 A

■Output tolerance ± 1 % at 25°C and ± 2 % in full temperature range

■Internal power and thermal limit

■Wide operating temperature range -40 °C to 125 °C

■Package available: TO-220, TO-220FP, DPAK, D2PAK, D2PAK/A

■Pinout compatibility with standard adjustable VREG

Description

The LD1085xx is a low drop voltage regulator able to provide up to 3 A of output current. Dropout is guaranteed at a maximum of 1.2 V at the maximum output current, decreasing at lower loads. The LD1085xx is pin to pin compatible with the older 3-terminal adjustable regulators, but has better performances in term of drop and output tolerance.

A 2.85 V output version is suitable for SCSI-2 active termination. Unlike PNP regulators, where a part of the output current is wasted as quiescent current, the LD1085xx quiescent current flows

TO-220		TO-220FP
DPAK	D2PAK	D2PAK/A

into the load, so increase efficiency. Only a 10 µF minimum capacitor is need for stability.

The device is supplied in TO-220, TO-220FP, DPAK, D2PAK and D2PAK/A. On chip trimming allows the regulator to reach a very tight output voltage tolerance, within ± 1 % at 25 °C.

The LD1085xx is available as Automotive Grade in TO-220FP package only, for the option of adjustable output voltage whose commercial part number is shown in the Table 11 (order codes). This device is qualified according to the specification AEC-Q100 of the Automotive market, in the temperature range -40 °C to

125 °C, and the statistical tests PAT, SYL, SBL are performed.

Table 1.	Device summary
	Part numbers
	LD1085XX		LD1085XX25
	LD1085XX15		LD1085XX33
	LD1085XX18		LD1085XX50
April 2008	Rev 22		1/28
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Contents	LD1085xx

Contents

1	Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. 3
2	Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. 4
3	Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	5
4	Schematic application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	6
5	Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	7
6	Typical application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	14
7	Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	18
8	Order codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	26
9	Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	27

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LD1085xx	Diagram

1 Diagram

Figure 1. Schematic diagram

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Pin configuration	LD1085xx

2 Pin configuration

Figure 2. Pin connections (top view)

TO-220	TO-220FP
D2PAK	D2PAK/A
	DPAK

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LD1085xx	Maximum ratings

3 Maximum ratings

Table 2.		Absolute maximum ratings
Symbol			Parameter					Value			Unit
VI			DC input voltage					30			V
IO			Output current			Internally limited					mA
PD			Power dissipation			Internally limited					mW
TSTG			Storage temperature range				-55 to +150				°C
TOP			Operating junction temperature range				-40 to +125				°C
Note:		Absolute maximum ratings are those values beyond which damage to the device may occur.
		Functional operation under these condition is not implied
Table 3.		Thermal data
Symbol			Parameter	TO-220		DPAK			D2PAK		Unit
									D2PAK/A
RthJC		Thermal resistance junction-case		3		8			3		°C/W
RthJA		Thermal resistance junction-ambient		50		100			62.5		°C/W

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Schematic application	LD1085xx

4 Schematic application

Figure 3. Application circuit

V		=	V			R2
	O			REF		1 + ------
						R
						1

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LD1085xx			Electrical characteristics
5	Electrical characteristics
Table 4.	Electrical characteristics of LD1085#15
	(VI = 4.5 V, CI = CO =10 µF, TA = -40 to 125 °C, unless otherwise specified).
Symbol	Parameter	Test condition	Min.	Typ.	Max.	Unit
V	Output voltage (1)	IO = 0 mA, TJ = 25°C	1.485	1.5	1.515	V
O		IO = 0 to 3 A, VI = 3.1 to 30 V	1.47	1.5	1.53	V
VO	Line regulation	IO = 0 mA, VI = 3.1 to 18 V, TJ = 25°C		0.2	4	mV
		IO = 0 mA, VI = 3.1 to 15 V		0.4	4	mV
VO	Load regulation	IO = 0 to 3 A, TJ = 25°C		2	10	mV
		IO = 0 to 3 A		4	20	mV
Vd	Dropout voltage	IO =3 A		1.3	1.5	V
Iq	Quiescent current	VI ≤ 30 V		5	10	mA
Isc	Short circuit current	VI - VO = 5 V	3.2	4.5		A
		VI - VO = 25 V	0.2	0.5		A
	Thermal regulation	TA = 25°C, 30ms pulse		0.008	0.04	%/W
SVR	Supply voltage rejection	f = 120 Hz, CO = 25 µF, IO = 3 A	60	72		dB
		VI = 7.5 ± 3 V
eN	RMS output noise voltage (%	TA = 25°C, f =10 Hz to 10 kHz		0.003		%
	of VO)
S	Temperature stability			0.5		%
S	Long term stability	TA = 125°C, 1000Hrs		0.5		%

1. See short-circuit current curve for available output current at fixed dropout.

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Electrical characteristics					LD1085xx
Table 5.	Electrical characteristics of LD1085#18
	(VI = 4.8 V, CI = CO =10 µF, TA = -40 to 125 °C, unless otherwise specified).
Symbol	Parameter	Test condition	Min.	Typ.	Max.	Unit
V	Output voltage (1)	IO = 0 mA, TJ = 25°C	1.782	1.8	1.818	V
O		IO = 0 to 3 A, VI = 3.4 to 30 V	1.764	1.8	1.836	V
VO	Line regulation	IO = 0 mA, VI = 3.4 to 18 V TJ = 25°C		0.2	4	mV
		IO = 0 mA, VI = 3.4 to 15 V		0.4	4	mV
VO	Load regulation	IO = 0 to 3 A, TJ = 25°C		2	10	mV
		IO = 0 to 3 A		4	20	mV
Vd	Dropout voltage	IO = 3 A		1.3	1.5	V
Iq	Quiescent current	VI ≤ 30 V		5	10	mA
Isc	Short circuit current	VI - VO = 5 V	3.2	4.5		A
		VI - VO = 25 V	0.2	0.5		A
	Thermal regulation	TA = 25°C, 30 ms pulse		0.008	0.04	%/W
SVR	Supply voltage rejection	f = 120 Hz, CO = 25 µF, IO = 3 A	60	72		dB
		VI = 7.5 ± 3 V
eN	RMS output noise voltage (% of	T = 25°C, f =10 Hz to 10 kHz		0.003		%
	VO)	A
S	Temperature stability			0.5		%
S	Long term stability	TA = 125°C, 1000 Hrs		0.5		%

1. See short-circuit current curve for available output current at fixed dropout.

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LD1085xx			Electrical characteristics
Table 6.	Electrical characteristics of LD1085#25
	(VI = 5.5 V, CI = CO =10 µF, TA = -40 to 125 °C, unless otherwise specified).
Symbol	Parameter	Test condition	Min.	Typ.	Max.	Unit
V	Output voltage (1)	IO = 0 mA, TJ = 25°C	2.475	2.5	2.525	V
O		IO = 0 to 3 A, VI = 4.1 to 30 V	2.45	2.5	2.55	V
VO	Line regulation	IO = 0 mA, VI = 4.1 to 18 V, TJ = 25°C		0.2	4	mV
		IO = 0 mA, VI = 4.1 to 18 V		0.4	4	mV
VO	Load regulation	IO = 0 to 3 A, TJ = 25°C		2	10	mV
		IO = 0 to 3 A		4	20	mV
Vd	Dropout voltage	IO = 3 A		1.3	1.5	V
Iq	Quiescent current	VI ≤ 30 V		5	10	mA
Isc	Short circuit current	VI - VO = 5 V	3.2	4.5		A
		VI - VO = 25 V	0.2	0.5		A
	Thermal regulation	TA = 25°C, 30ms pulse		0.008	0.04	%/W
SVR	Supply voltage rejection	f = 120 Hz, CO = 25µF, IO = 3 A	60	72		dB
		VI = 7.5 ± 3 V
eN	RMS output noise voltage (%	TA = 25°C, f =10 Hz to 10 kHz		0.003		%
	of VO)
S	Temperature stability			0.5		%
S	Long term stability	TA = 125°C, 1000 Hrs		0.5		%

1. See short-circuit current curve for available output current at fixed dropout.

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