AME AME1085DCBT, AME1085AMCT, AME1085ACDT-3, AME1085ACDT, AME1085ACBT, AME1085DMCT, AME1085DCDT-3, AME1085DCDT Datasheet

Analog Microelectronics, Inc.

AME1085

3A Low Dropout

Positive Voltage Regulator

n General Description

The AME1085 is a 3A low-dropout positive voltage regulator. It is available in fixed and adjustable output voltage versions. Overcurrent and thermal protection are integrated onto the chip. Output current will limit as it reaches the pre-set current or temperature limit. At full rated output current the dropout voltage is 1.4V (max.). AME1085 series regulators provide excellent regulation over line, load and temperature variations.

n Key Features

lLow dropout voltage 1.2V typically at 3A

lAdjustable or 3.3V fixed voltage

lLine regulation typically 0.015%

lLoad regulation typically 0.05%

lAdjust pin (ADJ) current less than 90υA

lOvercurrent protection

lThermal protection

lAvailable in TO-220, TO-263, TO-252

n Applications

lHigh Efficiency Linear Regulators

lPost Regulators for Switching Supplies

l5V to 3.3V Voltage Converter

lBattery Charger

n Functional Block Diagram

Input

Current

Limiting

Amplifier

	Thermal	Output
	Protection

Error

Amp. Bandgap ADJ/GN D

Reference

Figure 1

n Typical Application

				AME1085
				V IN	V O U T
					GND
4.75V to 5.25V			10μF Tan					10μF Tan Load

Figure 2

1

Analog Microelectronics, Inc.

AME1085

3A Low Dropout

Positive Voltage Regulator

n Pin Configuration

To-263 Front View

To-263-2 Front View

AME 1085

1 2 3

AME 1085

1 2 3

A D J / G N D V O U T V IN

A D J / G N D V O U T V IN

To-252-2 Front View			TO-252-2 Front view

AME1085

	AME 1085							1	2	3
1			2			3
								ADJ/	VOUT	VIN
A D J / G N D V O U T						V IN
								GND

2

Analog Microelectronics, Inc.

AME1085

3A Low Dropout

Positive Voltage Regulator

n Ordering Information

Part Number	Marking	Output Voltage	Package
	AME1085
AME1085ACBT	ACBT	ADJ	TO-220
	YYWW
	AME1085
AME1085DCBT	DCBT	3.3	TO-220
	YYWW
	AME1085
AME1085ACDT-3	ACDT-3	ADJ	TO-263-3
	YYWW
	AME1085
AME1085DCDT-3	DCDT-3	3.3	TO-263-3
	YYWW
	AME1085
AME1085ACDT	ACDT	ADJ	TO-263-2
	YYWW
	AME1085
AME1085DCDT	DCDT	3.3	TO-263-2
	YYWW
	AME1085
AME1085AMCT	AMCT	ADJ	TO-252-2
	YYWW
	AME1085
AME1085MCT*	MCT	3.3	TO-252-2
	YYWW

* This differs from our standard part numbering scheme due to historical precedent

n Absolute Maximum Ratings

Parameter			Symbol	Maximum	Units
Input Voltage			VIN	7	V
Thermal Resistance		TO-220		2.5
		TO-263	θJC	2.5
(Junction to Case)
		TO-252		15	0C/W
Thermal Resistance		TO-220		50
		TO-263	θJA	60
(Junction to Ambient)
		TO-252		90
Operating Junction Temperature Range			TJ	0 to 125
Storage Temperature Range			TSTG	-65 to 150	0C
Lead Temperature ( 10 sec )			TLEAD	260

3

Analog Microelectronics, Inc.

AME1085

3A Low Dropout

Positive Voltage Regulator

n Electrical Characteristics

AME1085AXXX

		Parameter	Symbol			Test Conditions		Min.	Typ.	Max.	Units
	Reference voltage		VREF	VIN = 5V			TJ =250C	1.238	1.250	1.262	V
	(adjustable voltage)			IO = 10mA			Over temp.	1.225		1.275
				V		= 2.75 - 7V	T =250C	-	0.015	0.2
	Line regulation		RegLINE	IN			J				%
				I	= 10mA		Over temp.	-	0.035	0.2
				O
	Load regulation		RegLOAD	VIN = 5V			TJ =250C	-	0.05	0.3	%
				I	= 10mA - 3A		Over temp.	-	0.2	0.4
				O
	Dropout voltage		VD	VIN = 2.75 - 7V			TJ =250C	-	1.2	1.4	V
	VOUT,	VREF = 1%		IO = 10mA - 3A			Over temp.	-	1.3	-
	Current limit		IS	VIN = 2.75 - 7V, Over temp.				3.0	-	-	A
	Temperature Coefficient		TC	VIN = 2.75 - 7V, IO = 10mA - 3A				-	0.005	-	%/OC
	Temperature stability		TS	VIN = 5V, IO = 500mA, Over temp.				-	0.5	-	%
	Minimum load current		IO	VIN = 5V				-	5	10	mA
	RMS output noise		VN	TJ =250C				-	0.003	-	%V0
	Ripple rejection ratio		RA	VIN = 5V, IO = 3A, Over temp.				60	72	-	dB
AME1085DXXX
		Parameter	Symbol			Test Conditions		Min.	Typ.	Max.	Units
	Output voltage		Vo	VIN = 5V			TJ =250C	3.267	3.300	3.333	V
	(fixed voltage)			IO = 0A			Over temp.	3.234		3.366
				V		=4.5 - 7V	T =250C	-	0.015	0.2
	Line regulation		RegLINE	IN			J				%
				I	= 0A		Over temp.	-	0.035	0.2
				O
	Load regulation		RegLOAD	VIN = 5V			TJ =250C	-	0.05	0.3	%
				I	= 0A - 3A		Over temp.	-	0.2	0.4
				O
	Dropout voltage		VD	VIN = 4.5 - 7V			TJ =250C	-	1.2	1.4	V
	VOUT,	VREF = 1%		IO = 0A - 3A			Over temp.	-	1.3	-
	Current limit		IS	VIN = 4.5 - 7V, Over temp.				3.0	-	-	A
	Quiescent current		IQ	VIN = 5V, Io=0A - 3A, Over temp.				-	12	13	mA
	(fixed model)
	Temperature Coefficient		TC	VIN = 4.5 - 7V, IO = 0A - 3A				-	0.005	-	%/0C
	Temperature stability		TS	VIN = 5V, IO = 500mA, Over temp.				-	0.5	-	%
	RMS output noise		VN	TJ =250C				-	0.003	-	%V0
	Ripple rejection ratio		RA	VIN = 5V, IO = 3A, Over temp.				60	72	-	dB

4

Analog Microelectronics, Inc.

AME1085

3A Low Dropout

Positive Voltage Regulator

nApplication Description

1.Output voltage adjustment

Like most regulators, the AME1085 regulates the output by comparing the output voltage to an

internally generated reference voltage. On the adjustable version, the VREF is available externally as 1.25V between VOUT and ADJ. The voltage ratio formed by R1 and R2 should be set to conduct 10mA (minimum output load). The output voltage is given by the following equation:

VOUT = VREF ( 1 + R2 ) + IADJ x R2 R1

On fixed versions of AME1085, the voltage divider is provided internally.

VIN		IN			O U T			VO U T
C 1				ADJ			VREF	R1
		IADJ
		50μA
								R2
V	O U T	= V	REF	(1+	R2 ) + I	ADJ	x R2
					R1
			Figure 3					VIN

3.Current limit protection

AME1085 is protected against overload conditions. Current protection is triggered at typically 4.5A.

4.Stability and load regulation

AME1085 requires a capacitor from VOUT to GND to provide compensation feedback to the

internal gain stage. This is to ensure stability at the output terminal. Typically, a 10μF tantalum or 50μF aluminum electrolytic is sufficient.

Note: It is important that the ESR for this capacitor does not exceed 0.5Ω.

The output capacitor dose not have a theoreti-

cal upper limit and increasing its value will increase stability. COUT = 100μF or more is typical for high current regulator design.

For the adjustable version, the best load regulation is accomplished when the top of the resistor divider (R1) is connected directly to the output pin of the AME1085. When so con-

nected, RP is not multiplied by the divider ratio. For fixed output versions, the top of R1 is internally connected to the output and ground pin can be connected to low side of the load.

R P

Parasitic

Line Resistance

IN O U T

ADJ

2.Thermal protection

AME1085 has thermal protection which limits junction temperature to 150OC. However, de-

vice	functionality is only guaranteed to a maxi-
mum	junction temperature of +125OC.

The power dissipation and junction temperature for AME1085 in TO-220 package are given by

R1

R L

(Connect R1 to case)

R2

PD = (VIN - VOUT) x IOUT								Connect
	x θJA)
TJUNCTION = TAMBIENT + ( PD
								R2 to load

Note: TJUNCTION must not exceed 125OC

Figure 4

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