ANALOG DEVICES ADR280 Service Manual

1.2 V Ultralow Power

V

V

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FEATURES

1.2 V precision output
Excellent line regulation: 2 ppm/V typical
High power supply ripple rejection: –80 dB at 220 Hz
Ultralow power supply current: 16 μA maximum
Temperature coefficient: 40 ppm/°C maximum
Low noise, 12.5 nV/√Hz typical
Operating supply range, 2.4 V to 5.5 V
Compact 3-lead SOT-23 and SC70 packages

APPLICATIONS

List GSM, GPRS, 3G mobile stations
Portable battery-operated electronics
Low voltage converter references
Wireless devices

GENERAL DESCRIPTION

The ADR280 is a 1.2 V band gap core reference with excellent
line regulation and power supply rejection designed specifically
for applications experiencing heavy dynamic supply variations,
such as data converter references in GSM, GPRS, and 3G
mobile station applications. Devices such as the AD6535 that
have an analog baseband IC with on-board baseband, audio
codecs, voltage regulators, and battery chargers rely on the
ability of the ADR280 to reject input battery voltage variations
during RF power amplifier activity.

In addition to mobile stations, the ADR280 is suitable for a
va

riety of general-purpose applications. Most band gap refer­ences include internal gain for specific outputs, which simplifies
the user’s design, but compromises on the cost, form factor, and
flexibility. The ADR280, on the other hand, optimizes the band
gap core voltage and allows users to tailor the voltage, current,
or transient response by simply adding their preferred op amps.

The ADR280 operates on a wide supply voltage range from

o 5.5 V. It is available in compact 3-lead SOT-23 and

2.4 V t
SC70 packages. The device is specified over the extended indus­trial temperature range of −40°C to +85°C.

High PSRR Voltage Reference

ADR280

PIN CONFIGURATIONS

V+

1

ADR280

2

OUT

Figure 1. 3-Lead SOT-23

(RT Suffi

1

OUT

ADR280

V+

2

Figure 2. 3-Lead SC70

(KS Suffix)

15

10

5

3V TO 5V

0

–5

LINE REGUL ATION (ppm/V)

–10

–15

–40 –20 0 20 40 60 80 100

Figure 3. Line Regulation vs. Temperature

TEMPERATURE (°C)

V–

3

03065-001

x)

3

V–

03065-002

03065-003

Rev. C

Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Anal og Devices for its use, nor for any infringements of patents or ot her
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] www.analog.com
Fax: [phone] ©2002–2007 Analog Devices, Inc. All rights reserved.

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TABLE OF CONTENTS

Features.............................................................................................. 1

Applications....................................................................................... 1

General Description ......................................................................... 1

Pin Configurations ........................................................................... 1

Revision History ............................................................................... 2

Specifications..................................................................................... 3

Electrical Characteristics ............................................................. 3

Absolute Maximum Ratings............................................................ 4

REVISION HISTORY

4/07—Rev. B to Rev. C

Updated Format..................................................................Universal

Changes to Figure 1, Figure 2.......................................................... 1

Deleted Pin Function Descriptions Section and Pin

onfigurations Section .................................................................... 2

C

Changes to Figure 20 and Figure 21............................................... 9

Updated Outline Dimensions....................................................... 10

10/04—Rev. A to Rev. B

Changes to Pin Configurations.........................................Universal

hanges to Ordering Guide............................................................ 2

C

Changes to Outline Dimensions..................................................... 7

Thermal Resistance.......................................................................4

ESD Caution...................................................................................4

Typical Performance Characteristics..............................................5

Theory of Operation .........................................................................7

Applications Information.................................................................8

Low Cost, Low Power Current Source .......................................8

Outline Dimensions....................................................................... 10

Ordering Guide .......................................................................... 11

6/03—Rev. 0 to Rev. A

Added SC70 package..........................................................Universal

hanges to Features ..........................................................................1

C

Changes to General Description .....................................................1

Changes to Specifications.................................................................2

Changes to Ordering Guide.............................................................2

Changes to TPCs 4, 6, and 7 ............................................................3

Updated SOT-23 Outline Dimensions ...........................................7

11/02—Revision 0: Initial Version

Rev. C | Page 2 of 12

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SPECIFICATIONS

ELECTRICAL CHARACTERISTICS

VIN = 2.55 V to 5.5 V, TA = 25°C, unless otherwise noted.

Table 1.

Parameter Symbol Conditions Min Typ1Max Unit

Output Voltage V
Temperature Coefficient TCVO 0°C < TA < 50°C 5 20 ppm/°C
–40°C < TA < +85°C 10 40 ppm/°C
Line Regulation ΔV
Supply Current IIN 2.4 V < VIN < 5.5 V, no load 10 16 μA
Ground Current I
Input Voltage Range VIN 2.4 5.5 V
Operating Temperature Range TA −40 +85 °C
Nominal Load Capacitance C
Output Noise Voltage VN rms f = 10 Hz to 10 kHz 12.5 μV rms
Voltage Noise Density eN f = 400 kHz 12.5 nV/√Hz
Power Supply Ripple Rejection2PSRR I
Start-Up Time tON 2 ms

1

Typical values represent average readings taken at room temperature.

2

Power supply ripple rejection measurement applies to a changing input voltage (VIN) waveform with a nominal 3.6 V baseline that drops to a 3 V value for 380 μs at a

4.6 ms repetition rate.

2.4 V < VIN < 5.5 V, 0 μA < I

OUT

/ΔVIN 2.55 V < VIN < 5.5 V, no load 2 12 ppm/V

OUT

V– grounded, I

GND

1 μF

OUT

= 10 μA −80 dB

LOAD

= 10 μA 12 20 μA

LOAD

< 10 μA, −40°C < TA < +85°C 1.195 1.200 1.205 V

OUT

Rev. C | Page 3 of 12

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ABSOLUTE MAXIMUM RATINGS

TA = 25°C, unless otherwise noted.

Table 2.

Parameter Rating

Supply Voltage 6 V
Storage Temperature Range −65°C to +150°C
Operating Temperature Range −40°C to +85°C
Junction Temperature Range −65°C to +150°C
Lead Temperature Range (Soldering, 60 Sec) 300°C

THERMAL RESISTANCE

θJA is specified for the worst-case conditions, that is, θJA is
specified for a device soldered in circuit board for surface­mount packages.

Table 3.

Package Type θJA θ

SOT-23 230 146 °C/W
SC70 376 102 °C/W

Unit

JC

Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.

ESD CAUTION

Rev. C | Page 4 of 12