Texas Instruments OPA381, OPA2381 Datasheet

OPA381

OPA2381

SBOS313B − AUGUST 2004 − REVISED NOVEMBER 2004

Precision, Low Power, 18MHz

Transimpedance Amplifier

FEATURES

DOVER 250kHz TRANSIMPEDANCE BANDWIDTH

DDYNAMIC RANGE: 5 Decades

DEXCELLENT LONG-TERM STABILITY

DLOW VOLTAGE NOISE: 10nV/√Hz

DBIAS CURRENT: 3pA

DOFFSET VOLTAGE: 25 V (max)

DOFFSET DRIFT: 0.1 V/°C (max)

DGAIN BANDWIDTH: 18MHz

DQUIESCENT CURRENT: 800 A

DFAST OVERLOAD RECOVERY

DSUPPLY RANGE: 2.7V to 5.5V

DSINGLE AND DUAL VERSIONS

DMicroPACKAGE: DFN-8, MSOP-8

APPLICATIONS

DPRECISION I/V CONVERSION

DPHOTODIODE MONITORING

DOPTICAL AMPLIFIERS

DCAT-SCANNER FRONT-END

DPHOTO LAB EQUIPMENT

	RF
	+5V
	7
2		OPA381		VOUT
			6	(0V to 4.4V)
CDIO DE				R
Photodiode				P
				(Optional
1MΩ	65pF			Pulldown
				Resistor)
			− 5V
		100kΩ
3
		75pF
	4

DESCRIPTION

The OPA381 family of transimpedance amplifiers provides 18MHz of Gain Bandwidth (GBW), with extremely high precision, excellent long-term stability, and very low 1/f noise. The OPA381 features an offset voltage of 25 V (max), offset drift of 0.1 V/°C (max), and bias current of 3pA. The OPA381 far exceeds the offset, drift, and noise performance that conventional JFET op amps provide.

The signal bandwidth of a transimpedance amplifier depends largely on the GBW of the amplifier and the parasitic capacitance of the photodiode, as well as the feedback resistor. The 18MHz GBW of the OPA381 enables a transimpedance bandwidth of > 250kHz in most configurations. The OPA381 is ideally suited for fast control loops for power level measurement on an optical fiber.

As a result of the high precision and low-noise characteristics of the OPA381, a dynamic range of 5 decades can be achieved. This capability allows the measurement of signal currents on the order of 10nA, and up to 1mA in a single I/V conversion stage. In contrast to logarithmic amplifiers, the OPA381 provides very wide bandwidth throughout the full dynamic range. By using an external pulldown resistor to –5V, the output voltage range can be extended to include 0V.

The OPA381 and OPA2381 are both available in MSOP-8 and DFN-8 (3mm x 3mm) packages. They are specified from –40°C to +125°C.

OPA381 RELATED DEVICES

	PRODUCT	FEATURES
	OPA380	90MHz GBW, 2.7V to 5.5V Supply
		Transimpedance Amplifier
	OPA132	16MHz GBW, Precision FET Op Amp ±15V
	OPA300	150MHz GBW, Low-Noise, 2.7V to 5.5V Supply
	OPA335	10 V VOS, Zero-Drift, 2.5V to 5V Supply
	OPA350	500 V VOS, 38MHz, 2.5V to 5V Supply
	OPA354	100MHz GBW CMOS, RRIO, 2.5V to 5V Supply
	OPA355	200MHz GBW CMOS, 2.5V to 5V Supply
	OPA656/7	230MHz, Precision FET, ±5V

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

All trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date. Products	Copyright 2004, Texas Instruments Incorporated
conform to specifications per the terms of Texas Instruments standard warranty.
Production processing does not necessarily include testing of all parameters.

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OPA381

OPA2381

www.ti.com

SBOS313B − AUGUST 2004 − REVISED NOVEMBER 2004

ABSOLUTE MAXIMUM RATINGS(1)

Voltage Supply . . . . . . . . . . . . . . . . . . . . .	. . . . . . .	. . . . . . . . . . . +7V
Signal Input Terminals(2), Voltage . . . . .	(V−) −0.5V to (V+) + 0.5V
Current . . . . . .	. . . . . . .	. . . . . . . . ±10mA
Short-Circuit Current(3) . . . . . . . . . . . . . . . . . . . . . . . . Continuous
Operating Temperature Range . . . . . . . .	. . . . . . .	−40 °C to +125°C
Storage Temperature Range . . . . . . . . . .	. . . . . . .	−65 °C to +150°C
Junction Temperature . . . . . . . . . . . . . . . .	. . . . . . . .	. . . . . . . +150°C
Lead Temperature (soldering, 10s) . . . . . .	. . . . . . . .	. . . . . . . +300°C
OPA381 ESD Rating (Human Body Model) . . . . . . .		. . . . . . . . 2000V
OPA2381 ESD Rating (Human Body Model) . . . . . .		. . . . . . . . 1500V

(1)Stresses above these ratings may cause permanent damage. Exposure to absolute maximum conditions for extended periods may degrade device reliability. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those specified is not implied.

(2)Input terminals are diode clamped to the power-supply rails. Input signals that can swing more than 0.5V beyond the supply rails should be current limited to 10mA or less.

(3)Short-circuit to ground; one amplifier per package.

PACKAGE/ORDERING INFORMATION(1)

ELECTROSTATIC DISCHARGE SENSITIVITY

This integrated circuit can be damaged by ESD. Texas

Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe

proper handling and installation procedures can cause damage.

ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.

			PACKAGE	SPECIFIED	PACKAGE	ORDERING	TRANSPORT
	PRODUCT	PACKAGE-LEAD		TEMPERATURE
			DESIGNATOR		MARKING	NUMBER	MEDIA, QUANTITY
				RANGE
	OPA381	MSOP-8	DGK	−40 °C to +125°C	A64	OPA381AIDGKT	Tape and Reel, 250
						OPA381AIDGKR	Tape and Reel, 2500
	OPA381	DFN-8	DRB	−40 °C to +125°C	A65	OPA381AIDRBT	Tape and Reel, 250
						OPA381AIDRBR	Tape and Reel, 3000
	OPA2381	MSOP-8	DGK	−40 °C to +125°C	A62	OPA2381AIDGKT	Tape and Reel, 250
						OPA2381AIDGKR	Tape and Reel, 2500
	OPA2381	DFN-8	DRB	−40 °C to +125°C	A63	OPA2381AIDRBT	Tape and Reel, 250
						OPA2381AIDRBR	Tape and Reel, 3000

(1) For the most current package and ordering information, see the Package Option Addendum located at the end of this data sheet.

PIN ASSIGNMENTS
Top View		OPA381				OPA381
NC(1)	1	8	NC(1)	NC(1)	1	Exposed	8	NC(1)
−In	2	7	V+	−In	2	Thermal	7	V+
	3	6			3	Die Pad	6
+In			Out	+In		on		Out
V− 4		5 NC(1)		V− 4		Underside	5 NC(1)
		MSOP−8				DFN−8
				NOTE: (1) NC indicates no internal connection.
		OPA2381				OPA2381
Out A	1	8	V+	Out A	1	Exposed	8	V+
− In A	2	7	Out B	− In A	2	Thermal	7	Out B
+In A	3	6	− In B		3	Die Pad	6	− In B
				+In A		on
V−	4	5	+In B	V−	4	Underside	5	+In B
		MSOP−8				DFN−8

2

OPA381

OPA2381

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SBOS313B − AUGUST 2004 − REVISED NOVEMBER 2004

ELECTRICAL CHARACTERISTICS: VS = +2.7V to +5.5V

Boldface limits apply over the temperature range, TA = −40 °C to +125°C.

All specifications at TA = +25°C, RL = 10kΩ connected to VS/2, and VOUT = VS/2, unless otherwise noted.

OPA381

PARAMETER

CONDITION

MIN

TYP

MAX

UNITS

OFFSET VOLTAGE

Input Offset Voltage

VOS

VS = +5V, VCM = 0V

7

25

µV

Drift

dVOS/dT

0.03

0.1

µV/°C

vs Power Supply

PSRR

VS = +2.7V to +5.5V, VCM = 0V

3.5

20

µV/V

Over Temperature

VS = +2.7V to +5.5V, VCM = 0V

20

µV/V

Long-Term Stability(1)

See Note

(1)

µV/V

Channel Separation, dc

1

INPUT BIAS CURRENT

Input Bias Current

IB

VCM = VS/2

3

±50

pA

Over Temperature

See Typical Characteristics

Input Offset Current

IOS

VCM = VS/2

±100

pA

6

NOISE

Input Voltage Noise, f = 0.1Hz to 10Hz

en

VS = +5V, VCM = 0V

3

µVPP

Input Voltage Noise Density, f = 10kHz

en

VS = +5V, VCM = 0V

70

nV/√Hz

Input Voltage Noise Density, f > 1MHz

en

VS = +5V, VCM = 0V

10

nV/√

Hz

Input Current Noise Density, f = 10kHz

in

VS = +5V, VCM = 0V

20

fA/√

Hz

INPUT VOLTAGE RANGE

Common-Mode Voltage Range

VCM

V−

(V+) − 1.8V

V

Common-Mode Rejection Ratio

CMRR

VS = +5V, (V−) < V CM < (V+) − 1.8V

95

110

dB

INPUT IMPEDANCE

Differential Capacitance

1

pF

Common-Mode Resistance and Capacitance

1013|| 2.5

Ω || pF

OPEN-LOOP GAIN

Open-Loop Voltage Gain

AOL

0.05V < VO < (V+) − 0.6V, V CM = VS/2, VS = 5V

110

135

dB

0V < VO < (V+) − 0.6V, V CM = 0V, RP = 10kΩ to −5V (2), VS = 5V

106

135

dB

FREQUENCY RESPONSE

Gain-Bandwidth Product

GBW

18

MHz

Slew Rate

SR

G = +1

12

V/µs

Settling Time, 0.0015%(3)

V = +5V, 4V Step, G = +1, OPA381

7

µs

Settling Time, 0.003%(3)

S

µs

V = +5V, 4V Step, G = +1, OPA2381

7

Overload Recovery Time(4), (5)

S

V • G = > V

200

ns

S

IN

OUTPUT

Voltage Output Swing from Positive Rail

RL = 10kΩ

400

600

mV

Voltage Output Swing from Negative Rail

RL = 10kΩ

30

50

mV

Voltage Output Swing from Positive Rail

R

P

= 10kΩ to −5V (2)

400

600

mV

Voltage Output Swing from Negative Rail

R

= 10kΩ to −5V (2)

−20

0

mV

P

Output Current

IOUT

10

mA

Short-Circuit Current

ISC

20

mA

Capacitive Load Drive

CLOAD

See

Typical Characteristics

Open-Loop Output Impedance

RO

F = 1MHz, IO = 0

250

Ω

POWER SUPPLY

Specified Voltage Range

VS

2.7

5.5

V

Quiescent Current (per amplifier)

IQ

IO = 0A

0.8

1

mA

Over Temperature

1.1

mA

TEMPERATURE RANGE

Specified and Operating Range

−40

+125

°C

Storage Range

−65

+150

°C

Thermal Resistance

qJA

°C/W

MSOP-8

150

DFN-8

65

°C/W

(1)High temperature operating life characterization of zero-drift op amps applying the techniques used in the OPA381 have repeatedly demonstrated randomly distributed variation approximately equal to measurement repeatability of 1µV. This consistency gives confidence in the stability and repeatability of these zero-

drift techniques.

(2)Tested with output connected only to RP, a pulldown resistor connected between VOUT and −5V, as shown in Figure 3. See also Applications section, Achieving Output Swing to Negative Rail.

(3)Transimpedance frequency of 250kHz.

(4)Time required to return to linear operation.

(5)From positive rail.

3

OPA381

OPA2381

www.ti.com

SBOS313B − AUGUST 2004 − REVISED NOVEMBER 2004

TYPICAL CHARACTERISTICS: VS = +2.7V to +5.5V

All specifications at TA = +25°C, RL = 10kΩ connected to VS/2, and VOUT = VS/2, unless otherwise noted.

	POWER−SUPPLY REJECTION RATIO AND
OPEN−LOOP GAIN AND PHASE vs FREQUENCY	COMMON−MODE REJECTION vs FREQUENCY

	140							200		140
	120				Phase			150		120
Open−LoopGain (dB)	100							100		100			PSRR
									PSRR,CMRR (dB)	80
	20							−100Phase()						CMRR
	80							50		60
	60							0		40
	40				Gain			−50		20
										0
	0							−150		−20
										−40
	−20							−200		−60
	10	100	1k	10k	100k	1M	10M	100M
										10	100	1k	10k	100k	1M	10M	100M
				Frequency (Hz)									Frequency (Hz)
			PHASE MARGIN vs LOAD CAPACITANCE								QUIESCENT CURRENT vs TEMPERATURE

	90							RS = 100Ω
	80
											(mA)
)	70								100pF
Margin(											Current
	50
	60								50kΩ
										RS
Phase					RS	= 50Ω					CL
	40										Quiescent
	30						RS = 0Ω
	20
	10
	0	100	200	300	400	500	600	700	800	900	1000
				CL Load Capacitance (pF)

1.00

0.90

0.85

0.80

5.5V

0.75

0.70

0.65

2.7V

0.60

0.55

0.50

−40 − 25	0	25	50	75	100	125
		Temperature (_C)

QUIESCENT CURRENT vs SUPPLY VOLTAGE

INPUT BIAS CURRENT vs TEMPERATURE

	1.00
	0.90
(mA)	0.85							(pA)
	0.80
Current								Current
	0.75
Quiescent	0.70							InputBias
	0.65
	0.60
	0.55
	0.50
	2.7	3.1	3.5	3.9	4.3	4.7	5.1	5.5
				Supply Voltage (V)

1000

100

10

1

−40 − 25	0	25	50	75	100	125
		Temperature (_C)

4

OPA381

OPA2381

www.ti.com

SBOS313B − AUGUST 2004 − REVISED NOVEMBER 2004

TYPICAL CHARACTERISTICS: VS = +2.7V to +5.5V (continued)

All specifications at TA = +25°C, RL = 10kΩ connected to VS/2, and VOUT = VS/2, unless otherwise noted.

Input Bias Current (pA)

		INPUT BIAS CURRENT									OUTPUT VOLTAGE SWING vs OUTPUT CURRENT
50		vs COMMON−MODE VOLTAGE							(V+)			(VS = 5.5V)
40
30									(V+) −	1
20		− IB						(V)
									(V+) −
0								Swing		2
10												+125_C
−10								Output	(V− ) + 2					+25°C
		+IB
−20
														−40_C
−30									(V− ) + 1
−40
−50									(V−)
0	0.5	1.0	1.5	2.0	2.5	3.0	3.5			0	5	10	15	20	25
		Common−Mode Voltage (V)										Output Current (mA)

Output Swing (V)

OUTPUT VOLTAGE SWING vs OUTPUT CURRENT

OFFSET VOLTAGE DRIFT

(V+)

(VS = 2.7V)

PRODUCTION DISTRIBUTION

(V+) − 0.35

(V+) − 0.70

(V+) − 1.05

Population

(V−) + 1.40

(V+) − 1.40

+125_C

+25_C

(V−) + 1.05

−40_C

(V−) + 0.70

(V−) + 0.35

(V−)

0

5

10

15

20

25

−0.09

−0.08

−0.07

−0.06

−0.05

−0.04 −0.03 −0.02 −0.01 0.00 0.01 0.02 0.03 0.04 0.05

Output Current (mA)

−0.10

0.06

0.07

0.08

0.09

0.10

Offset Voltage Drift (µV/_C)

	OFFSET VOLTAGE PRODUCTION DISTRIBUTION
Population										Bandwidth (MHz)
										Gain
−25.00	−20.00	−15.00	−10.00	−5.00	0.00	5.00	10.00	15.00	20.00	25.00
				Offset Voltage (µV)

GAIN BANDWIDTH vs POWER SUPPLY VOLTAGE

20

19

18

17

16

15

14

13

12

2.5

3.0

3.5

4.0

4.5

5.0

5.5

Power Supply Voltage (V)

5

OPA381

OPA2381

www.ti.com

SBOS313B − AUGUST 2004 − REVISED NOVEMBER 2004

TYPICAL CHARACTERISTICS: VS = +2.7V to +5.5V (continued)

All specifications at TA = +25°C, RL = 10kΩ connected to VS/2, and VOUT = VS/2, unless otherwise noted.

Circuit for Transimpedance Amplifier Characteristic curves on this page.

CF

RF

CSTRAY

OPA381

CDIODE

TRANSIMPEDANCE AMP CHARACTERISTIC

	150							CDIODE = 50pF
dB)	140
	130	RF = 10MΩ
in	120
(V/A	110	R	= 1MΩ	CF = 1pF
	100	F
Gain
	90	RF = 100kΩ			CF = 3pF
Transimpedance	80
	70	R	= 10kΩ		C	= 8pF
	60	F			F
	50
	40
	30
	20	CSTRAY (parasitic) = 0.2pF
	10
	100		1k	10k	100k		1M	10M	100M
					Frequency (Hz)

TRANSIMPEDANCE AMP CHARACTERISTIC

	150						CDIODE = 10pF
dB)	140
	130	RF = 10MΩ
in	120
(V/A
	110	RF	= 1MΩ	CF	= 0.5pF
	100
Gain
	90	RF = 100kΩ			CF = 2pF
Transimpedance	80
	70	RF = 10kΩ
	60				CF = 4pF
	50
	40
	30	CSTRAY (parasitic) = 0.2pF
	20
	10
	100		1k	10k	100k	1M	10M	100M

Frequency (Hz)

TRANSIMPEDANCE AMP CHARACTERISTIC

	150						CDIODE = 100pF
dB)	140
	130	RF = 10MΩ		CF = 0.5pF
in	120
(V/A	110	R	= 1MΩ	CF = 1pF
	100	F
Gain
	90	RF = 100kΩ			CF = 4pF
Transimpedance	80
	70	R	= 10kΩ		C = 12pF
	60	F			F
	50
	40
	30
	20	CSTRAY (parasitic) = 0.2pF
	10
	100		1k	10k	100k	1M	10M	100M
				Frequency (Hz)

TRANSIMPEDANCE AMP CHARACTERISTIC

	150						CDIODE = 20pF
dB)	140
	130	RF = 10MΩ
in	120
(V/A
	110	RF = 1MΩ		CF = 0.5pF
Gain	100
	90	RF = 100kΩ			C	= 2pF
Transimpedance	80				F
	70	RF = 10kΩ
	60				CF = 5pF
	50
	40
	30	CSTRAY (parasitic) = 0.2pF
	20
	10
	100		1k	10k	100k	1M	10M	100M
					Frequency (Hz)

TRANSIMPEDANCE AMP CHARACTERISTIC

	150						CDIODE = 1pF
dB)	140
	130	RF = 10MΩ
in	120
(V/A
	110	RF = 1MΩ
	100
Gain					CF = 0.5pF
	90	RF = 100kΩ
Transimpedance	80
	70	RF = 10kΩ				CF = 2pF
	60
	50
	40
	30
	20
		CSTRAY (parasitic) = 0.2pF
	10
	100		1k	10k	100k	1M	10M	100M

Frequency (Hz)

6

OPA381

OPA2381

www.ti.com

SBOS313B − AUGUST 2004 − REVISED NOVEMBER 2004

TYPICAL CHARACTERISTICS: VS = +2.7V to +5.5V (continued)

All specifications at TA = +25°C, and RL = 10kΩ connected to VS/2, unless otherwise noted.

SMALL−SIGNAL STEP RESPONSE (with or without pull−down)

200kHz (CF = 16pF)

1MHz

(CF = 3pF)

50mV/div	CF
	50kΩ
	OPA381

10kΩ

VP VP = 0V or − 5V

Time (100ns/div)

LARGE−SIGNAL STEP RESPONSE (without pull−down)

200kHz 1MHz (CF = 16pF)

(CF = 3pF)

1V/div	CF
	50kΩ
	OPA381

10kΩ

Time (100ns/div)

LARGE−SIGNAL STEP RESPONSE (with pull−down)

	1V/div		50kΩ
			3pF
			O PA3 81
			10kΩ
			−5V
			Time (100ns/div)
	6	OVERLOAD RECOVERY
		VOUT		40pF
(V/div)				20kΩ
	4			250µA
OUT	2		IIN	OPA381
				10kΩ
V		Nonlinear	Linear	VP
		Operation	Operation
	0	OPA381
(mA/div)
	0.8	OPA2381
				VP = 0V or − 5V
	0	IIN
IN
I

0 100 200 300 400 500 600 700 800 900 1000

Time (ns)

Input Voltage Noise (nV/√(Hz)

INPUT VOLTAGE NOISE SPECTRAL DENSITY

1000

100

10

1

10	100	1k	10k	100k	1M	10M
			Frequency (Hz)

Channel Separation (dB)

CHANNEL SEPARATION vs INPUT FREQUENCY

160 OPA2381

140

120

100

80

60

40

20

0

−20

−40

10

100

1k

10k

100k

1M

10M

100M

Input Frequency (Hz)

7