Datasheet

ManualsBrandsANALOG DEVICES ManualsLinear ICsLinear IC - Op-amp Multi-purpose SOT 23 5

20 μA Maximum, Rail-to-Rail I/O,

Zero Input Crossover Distortion Amplifiers

AD8505/AD8506/AD8508

Rev. E

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FEATURES

PSRR: 100 dB minimum

CMRR: 105 dB typical

Very low supply current: 20 μA per amplifier maximum

1.8 V to 5 V single supply or ±0.9 V to ±2.5 V dual supply

Rail-to-rail input/output

Low noise: 45 nV/√Hz at 1 kHz

2.5 mV offset voltage maximum

Very low input bias current: 1 pA typical

APPLICATIONS

Pressure and position sensors

Remote security

Bio sensors

IR thermometers

Battery-powered consumer equipment

Hazard detectors

GENERAL DESCRIPTION

The AD8505/AD8506/AD8508 are single, dual, and quad micro-

power amplifiers featuring rail-to-rail input/output swings while

operating from a single 1.8 V to 5 V power supply or from dual

±0.9 V to ±2.5 V power supplies. Using a new circuit technology,

these amplifiers offer zero input crossover distortion (excellent

PSRR and CMRR performance) and low bias current while

operating with a supply current of less than 20 µA per amplifier.

This amplifier family offers the lowest noise in its power class.

This combination of features makes the AD8505/AD8506/AD8508

amplifiers ideal choices for battery-powered applications because

they minimize errors due to power supply voltage variations over

the lifetime of the battery and maintain high CMRR even for a rail-

to-rail input op amp. Remote battery-powered sensors, handheld

instrumentation, consumer equipment, hazard detection (for

example, smoke, fire, and gas), and patient monitors can benefit

from the features of the AD8505/AD8506/AD8508 amplifiers.

The AD8505/AD8506/AD8508 are specified for both the industrial

temperature range of −40°C to +85°C and the extended industrial

temperature range of −40°C to +125°C. The AD8505 single ampli-

fier is available in a tiny 5-lead SOT-23 and a 6-ball WLCSP

packages. The AD8506 dual amplifier is available in 8-lead MSOP

and 8-ball WLCSP packages. The AD8508 quad amplifier is

available in 14-lead TSSOP and 14-ball WLCSP packages. The

AD8505/AD8506/AD8508 are members of a growing series of

zero crossover distortion op amps offered by Analog Devices,

Inc., including the ADA4505-1/ADA4505-2/ADA4505-4, that

operate from a single 1.8 V to 5 V supply or from dual ±0.9 V to

±2.5 V power supplies.

PIN CONFIGURATIONS

OUT

+IN

V–

V+

–IN

AD8505

TOP VIEW

(Not to Scale)

06900-051

06900-100

OUT V+

V–

+IN –IN

TOP VIEW

(BALL SIDE DOWN)

Not to Scale

A1 A2

B1 B2

C1 C2

BALL A1

INDICATOR

AD8505

NC = NO CONNECT

Figure 1. 5-Lead SOT-23 (RJ-5) Figure 2. 6-Ball WLCSP (CB-6-7)

OUT A

–IN A

+IN A

V–

V+

OUT B

–IN B

+IN B

AD8506

TOP VIEW

(Not to Scale)

06900-002

TOP VIEW

(BALL SIDE DOWN)

Not to Scale

BALL A1

CORNER

A1 A2 A3

B1 B3

C1 C2 C3

AD8506

+IN B V– +IN A

–IN B –IN A

OUT B V+ OUT A

06900-001

Figure 3. 8-Lead MSOP (RM-8) Figure 4. 8-Ball WLCSP (CB-8-2)

OUT A

–IN A

+IN A

V+

OUT D

–IN D

+IN D

V–

+IN B

–IN B

OUT B

+IN C

–IN C

OUT C

06900-045

AD8508

TOP VIEW

(Not to Scale)

TOP VIEW

(BALL SIDE DOWN)

Not to Scale

06900-104

OUTD OUTA –INA

–IND V– +INA

+IND +INB

+INC V+ –INB

–INC OUTC

AD8508

OUTB

BALL A1

CORNER

Figure 5. 14-Lead TSSOP (RU-14) Figure 6. 14-Ball WLCSP (CB-14-1)

Summary of content (20 pages)

PAGE 1
20 μA Maximum, Rail-to-Rail I/O, Zero Input Crossover Distortion Amplifiers AD8505/AD8506/AD8508 FEATURES V– 2 AD8505 5 The AD8505/AD8506/AD8508 are specified for both the industrial temperature range of −40°C to +85°C and the extended industrial temperature range of −40°C to +125°C. The AD8505 single amplifier is available in a tiny 5-lead SOT-23 and a 6-ball WLCSP packages. The AD8506 dual amplifier is available in 8-lead MSOP and 8-ball WLCSP packages.
PAGE 2
AD8505/AD8506/AD8508 TABLE OF CONTENTS Features .............................................................................................. 1 ESD Caution...................................................................................5 Applications ....................................................................................... 1 Typical Performance Characteristics ..............................................6 General Description ............................................................
PAGE 3
AD8505/AD8506/AD8508 SPECIFICATIONS ELECTRICAL CHARACTERISTICS—1.8 V OPERATION VSY = 1.8 V, VCM = VSY/2, TA = 25°C, RL = 100 kΩ to GND, unless otherwise noted. Table 1. Parameter INPUT CHARACTERISTICS Offset Voltage Input Bias Current Symbol Conditions VOS 0 V ≤ VCM ≤ 1.8 V −40°C ≤ TA ≤ +125°C Min IB Typ Max Unit 0.5 2.5 3.5 10 100 600 5 50 100 1.8 115 mV mV pA pA pA pA pA pA V dB dB dB dB 2.5 220 3 4.
PAGE 4
AD8505/AD8506/AD8508 ELECTRICAL CHARACTERISTICS—5 V OPERATION VSY = 5 V, VCM = VSY/2, TA = 25°C, RL = 100 kΩ to GND, unless otherwise noted. Table 2. Parameter INPUT CHARACTERISTICS Offset Voltage Input Bias Current Symbol Conditions VOS 0 V ≤ VCM ≤ 5 V −40°C ≤ TA ≤ +125°C Min IB Typ Max Unit 0.5 2.5 3.5 10 100 600 5 50 130 5 120 mV mV pA pA pA pA pA pA V dB dB dB dB 2 220 3 4.
PAGE 5
AD8505/AD8506/AD8508 ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE Table 3. Parameter Supply Voltage Input Voltage Input Current1 Differential Input Voltage2 Output Short-Circuit Duration to GND Storage Temperature Range Operating Temperature Range Junction Temperature Range Lead Temperature (Soldering, 60 sec) θJA is specified for the worst-case conditions, that is, a device soldered in a circuit board for surface-mount packages with its exposed paddle soldered to a pad, if applicable.
PAGE 6
AD8505/AD8506/AD8508 TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted. 250 250 VSY = 1.8V VCM = VSY/2 VSY = 5V VCM = VSY/2 200 NUMBER OF AMPLIFIERS 150 100 150 100 –3 –2 –1 0 1 2 3 4 VOS (mV) 0 –4 06900-003 0 –4 –3 1 2 3 4 12 VSY = 5V –40°C ≤ TA ≤ +125°C VSY = 1.
PAGE 7
AD8505/AD8506/AD8508 TA = 25°C, unless otherwise noted. –115 –120 VSY = 1.8V VSY = 5V –125 –120 VOS (µV) VOS (µV) –130 –125 –130 –135 –140 –135 0.6 0.8 1.0 VCM (V) 1.2 1.4 1.6 1.8 –150 500 450 450 IB (pA) 500 400 350 300 300 250 250 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 VCM (V) 200 5 VSY = 5V 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 VCM (V) Figure 14. Input Bias Current vs. Input Common-Mode Voltage at 125°C Figure 17. Input Bias Current vs.
PAGE 8
AD8505/AD8506/AD8508 TA = 25°C, unless otherwise noted. 10k OUTPUT VOLTAGE TO SUPPLY RAIL (mV) 1k 100 VOL VDD – VOH 10 1 0.1 0.001 0.01 0.1 LOAD CURRENT (mA) 1 10 1k 1 0.1 0.01 0.001 0.01 0.1 1 LOAD CURRENT (mA) 10 100 Figure 22. Output Voltage to Supply Rail vs.
PAGE 9
AD8505/AD8506/AD8508 TA = 25°C, unless otherwise noted.
PAGE 10
AD8505/AD8506/AD8508 TA = 25°C, unless otherwise noted. 100 90 80 80 CMRR (dB) 90 70 70 60 60 50 50 100 1k 10k FREQUENCY (Hz) 100k 1M 40 10 Figure 31. CMRR vs. Frequency 1k 10k FREQUENCY (Hz) VSY = 1.8V 90 80 80 70 70 60 60 PSRR (dB) 90 50 40 PSRR+ 20 VSY = 5V 50 40 PSRR+ 20 10 10 1k 10k 100k 1M FREQUENCY (Hz) 06900-023 100 0 10 100 100k 1M 80 80 VSY = 1.
PAGE 11
AD8505/AD8506/AD8508 TA = 25°C, unless otherwise noted. VSY = 1.8V RL = 100kΩ CL = 200pF G=1 TIME (100µs/DIV) 06900-035 06900-033 VOLTAGE (1V/DIV) VOLTAGE (500mV/DIV) VSY = 5V RL = 100kΩ CL = 200pF G=1 TIME (100µs/DIV) Figure 37. Large-Signal Transient Response Figure 40. Large-Signal Transient Response VSY = 1.8V RL = 100kΩ CL = 200pF G=1 TIME (100µs/DIV) Figure 38. Small-Signal Transient Response Figure 41.
PAGE 12
AD8505/AD8506/AD8508 TA = 25°C, unless otherwise noted. –40 –60 –70 –80 –90 –100 10kΩ –60 –70 –80 –90 –100 –110 1k 10k FREQUENCY (Hz) 100k Figure 43. Channel Separation vs. Frequency –120 100 1k 10k FREQUENCY (Hz) Figure 44. Channel Separation vs. Frequency Rev. E | Page 12 of 20 100k 06900-048 –110 –120 100 VSY = 5V VIN = 4V p-p 100kΩ –50 CHANNEL SEPARATION (dB) 10kΩ 06900-049 CHANNEL SEPARATION (dB) –50 –40 VSY = 1.8V VIN = 1.
PAGE 13
AD8505/AD8506/AD8508 THEORY OF OPERATION VDD The AD8505/AD8506/AD8508 are unity-gain, stable, CMOS, railto-rail input/output operational amplifiers designed to optimize performance in current consumption, PSRR, CMRR, and zero crossover distortion, all embedded in a small package. The typical offset voltage is 500 μV, with a low peak-to-peak voltage noise of 2.8 μV from 0.1 Hz to 10 Hz and a voltage noise density of 45 nV/√Hz at 1 kHz.
PAGE 14
AD8505/AD8506/AD8508 The charge pump has been carefully designed so that switching noise components at any frequency, both within and beyond the amplifier bandwidth, are much lower than the thermal noise floor. Therefore, the spurious-free dynamic range (SFDR) is limited only by the input signal and the thermal or flicker noise. There is no intermodulation between the input signal and the switching noise. Figure 48, the input offset voltage vs.
PAGE 15
AD8505/AD8506/AD8508 APPLICATIONS INFORMATION A pulse oximeter is a noninvasive medical device used for continuously measuring the percentage of hemoglobin (Hb) saturated with oxygen and the pulse rate of a patient. Hemoglobin that is carrying oxygen (oxyhemoglobin) absorbs light in the infrared (IR) region of the spectrum; hemoglobin that is not carrying oxygen (deoxyhemoglobin) absorbs visible red (R) light.
PAGE 16
AD8505/AD8506/AD8508 the I-to-V converter requires low input bias current. The AD8505/AD8506/AD8508 are excellent choices because these amplifiers provide 1 pA typical and 10 pA maximum of input bias current at ambient temperature. FOUR-POLE, LOW-PASS BUTTERWORTH FILTER FOR GLUCOSE MONITOR There are several methods of glucose monitoring: spectroscopic absorption of infrared light in the 2 μm to 2.
PAGE 17
AD8505/AD8506/AD8508 OUTLINE DIMENSIONS 3.00 2.90 2.80 5 1.70 1.60 1.50 1 4 2 3.00 2.80 2.60 3 0.95 BSC 1.90 BSC 1.45 MAX 0.95 MIN 0.15 MAX 0.05 MIN 0.20 MAX 0.08 MIN 10° 5° 0° SEATING PLANE 0.50 MAX 0.35 MIN 0.55 0.45 0.35 0.20 BSC 121608-A 1.30 1.15 0.90 COMPLIANT TO JEDEC STANDARDS MO-178-AA Figure 51. 5-Lead Small Outline Transistor Package [SOT-23] (RJ-5) Dimensions shown in millimeters 0.945 0.905 0.865 0.645 0.600 0.555 0.415 0.400 0.385 BALL A1 IDENTIFIER SEATING PLANE 0.
PAGE 18
AD8505/AD8506/AD8508 3.20 3.00 2.80 8 3.20 3.00 2.80 1 5.15 4.90 4.65 5 4 PIN 1 IDENTIFIER 0.65 BSC 0.95 0.85 0.75 15° MAX 1.10 MAX 0.40 0.25 0.80 0.55 0.40 0.23 0.09 6° 0° 100709-B 0.15 0.05 COPLANARITY 0.10 COMPLIANT TO JEDEC STANDARDS MO-187-AA Figure 53. 8-Lead Mini Small Outline Package [MSOP] (RM-8) Dimensions shown in millimeters 0.650 0.595 0.540 1.460 1.420 SQ 1.380 SEATING PLANE 3 2 1 0.340 0.320 0.300 BALL 1 IDENTIFIER A B 0.50 BALL PITCH 0.380 0.355 0.
PAGE 19
AD8505/AD8506/AD8508 5.10 5.00 4.90 14 8 4.50 4.40 4.30 6.40 BSC 1 7 PIN 1 0.65 BSC 0.15 0.05 COPLANARITY 0.10 1.20 MAX 0.20 0.09 SEATING PLANE 0.30 0.19 0.75 0.60 0.45 8° 0° 061908-A 1.05 1.00 0.80 COMPLIANT TO JEDEC STANDARDS MO-153-AB-1 Figure 55. 14-Lead Thin Shrink Small Outline Package [TSSOP] (RU-14) Dimensions shown in millimeters 0.650 0.595 0.540 1.50 1.46 1.42 0.25 BSC 0.25 BSC 3 SEATING PLANE 2 0.25 BSC 0.25 BSC 1 A BALL 1 IDENTIFIER 0.50 BSC B 3.00 2.96 2.92 0.340 0.
PAGE 20
AD8505/AD8506/AD8508 ORDERING GUIDE Model1 AD8505ARJZ-R2 AD8505ARJZ-R7 AD8505ARJZ-RL AD8505ACBZ-R7 AD8505ACBZ-RL AD8506ACBZ-REEL AD8506ACBZ-REEL7 AD8506ARMZ AD8506ARMZ-R7 AD8506ARMZ-REEL AD8508ARUZ AD8508ARUZ-REEL AD8508ACBZ-REEL AD8508ACBZ-REEL7 1 Temperature Range −40°C to +125°C −40°C to +125°C −40°C to +125°C −40°C to +125°C −40°C to +125°C −40°C to +125°C −40°C to +125°C −40°C to +125°C −40°C to +125°C −40°C to +125°C −40°C to +125°C −40°C to +125°C −40°C to +125°C −40°C to +125°C Package Description