JFET and OpAmp

Pyroelectric detectors of InfraTec use for the first signal processing stage Junction Field Effect Transistors (JFET) and CMOS Operational Amplifiers (OpAmp) built-in in the detector housing. Specifications are adapted for high-impedance pyroelectric elements.

1 Standard JFET – For single and multi color detectors

Features Very low voltage and current noise

High input impedance

Full performance from low-voltage power supply, down to 2.5 V

Low Gate leakage current for improved system accuracy

Absolute maximum ratings Gate-Source / Gate-Drain voltage: -50 V

Power dissipation: 50 mW

Specifications (TA = 25 °C unless otherwise noted)

Parameter Symbol Test Condition Min Typ Max UnitStatic

Gate-Source Breakdown Voltage -V(BR)GSS IG = -1 µA, VDS = 0 V 50 60 V

Gate-Source Cutoff Voltage -VGS(off) ID = 0.1 µA, VDS = 15 V 0.4 1.5Saturation Drain Current IDSS VDS = 15 V, VGS = 0 V 0.5 1.5 mA

Gate Reverse Current -IGSS VDS = 0 V, VGS = -30 V, TA = 25 °C 2 pA

VDS = 0 V, VGS = -30 V, TA = 150 °C 100 nAGate Operating Current -IG ID = 0.1 mA, VDG = 15 V 2

pADrain Cutoff Current ID(off) VDS = 15 V, VGS = -5 V 50Gate-Source Forward Voltage VGS(F) IG = 1 mA, VDS = 0 V 0.7 V

Dynamic Common-Source Forward Transconductance

gfs VDS = 15 V, VGS = 0 V, f = 1 kHz

0.8 2.2 2.4 mS

Common-Source Output Transconductance

gos 15 µS

Drain-Source On-Resistance rDS(on) VDS = 0 V, VGS = 0 V, f = 1 kHz 1,700 Common-Source Input Capacitance

Ciss VDS = 15 V, VGS = 0 V, f = 1 MHz

3.5 7pF

Common-Source Reverse Transfer Capacitance

Crss 1.2 3

Equivalent Input Noise Voltage en VDS = 10 V, VGS = 0 V, f = 1 kHz 6 nV/Hz

1

JFET and OpAmp

Standard JFET Specifications (TA = 25 °C unless otherwise noted)

10

0

8

6

4

2

0 –5–4–3–2–1

5

4

1

3

2

0

Drain Current and Transconductancevs. Gate-Source Cutoff Voltage

VGS(off) – )V(egatloVffotuCecruoS-etaG

IDSS @V DS = 10 V,V GS = 0 Vgfs @V DS = 10 V,V GS = 0 Vf = 1 kHz

gfs

IDSS

gfs

– Forward

Transconductance(m

S)

I DSS

– Sa

tura

tion

Dra

in C

urre

nt (m

A)

0.1 pA

1 pA

10 pA

100 pA

1 nA

10 nA

810 12 03426

Gate Leakage Current

VDG – Drain-Gate Voltage (V)

IGSS @ 125 C

IGSS @ 25 C

TA = 125 C

TA = 25 C

500 mA

500 mA

ID = 100 mA

ID = 100 mAI G–

Gat

e Le

akag

e (A

)

© 2001 Vishay Siliconix

11.010.0

2

1.6

0.8

0.4

0

Common-Source Forward Transconductancevs. Drain Current

ID – Drain Current (mA)

TA = –55 C

125 C

VGS(off) = –1.5 V

1.2

VDS = 10 Vf = 1 kHz

25 C

g fs

– Fo

rwar

dTr

ansc

ondu

ctan

ce(m

S)

500

0 –0.3–0.2–0.1 –0.4 –0.5

400

300

200

100

0

Transfer Characteristics

VGS – Gate-Source Voltage (V)

TA = –55 C

125 C

VGS(off) = –0.7 V VDS = 10 V

25 C

I D–

Dra

in C

urre

nt(

µA)

k001k100101 10 k

20

16

12

8

4

0

Equ iva lent Inpu t No ise Vo ltage vs. F requency

f – Frequency (Hz)

VDS = 10 V

ID = 100 mA

ID = IDSS

en–

Noi

seVo

ltage

nV/

Hz

11.00.01

200

160

120

80

40

0

ID – Drain Current (mA)

AV

gfs RL1 RLgos

RL10 VID

Assume V DD = 15 V, V DS = 5 V

VGS(off ) = –0.7 V

–1.5 V

Circuit Voltage Gain vs. Drain Current

A V–

Volta

ge G

ain

2

JFET and OpAmp

2 Special JFET – Design for single and multi color detectors (on request)

Benefits Reliable operation at high temperature or increased ionizing radiation

Disadvantage related to standard JFET Lower gain; higher output impedance

Features Ultra high input impedance

Low Gate leakage current for improved system accuracy

Absolute maximum ratings Gate-Source / Gate-Drain voltage: -50 V

Power dissipation: 50 mW

Specifications (TA = 25 °C unless otherwise noted)

Parameter Symbol Test Condition Min Typ Max UnitStatic

Gate-Source Breakdown Voltage -V(BR)GSS IG = -1 µA, VDS = 0 V 40 50 V

Gate-Source Cutoff Voltage -VGS(off) ID = 0.1 µA, VDS = 15 V 0.4 1.5Saturation Drain Current IDSS VDS = 15 V, VGS = 0 V 30 90 µA

Gate Reverse Current -IGSS VDS = 0 V, VGS = -20 V, TA = 25 °C 1 pA

VDS = 0 V, VGS = -20 V, TA = 150 °C 2.5 nAGate Operating Current -IG ID = 0.1 mA, VDG = 15 V 0.2

pADrain Cutoff Current ID(off) VDS = 15 V, VGS = -5 V 0.2 10Gate-Source Forward Voltage VGS(F) IG = 1 mA, VDS = 0 V 0.7 V

Dynamic Common-Source Forward Transconductance

gfs VDS = 15 V, VGS = 0 V, f = 1 kHz

70 175 210 µS

Common-Source Output Transconductance

gos

3 µS

Drain-Source On-Resistance rDS(on) VDS = 0 V, VGS = 0 V, f = 1 kHz 18 kCommon-Source Input Capacitance

Ciss VDS = 15 V, VGS = 0 V, f = 1 MHz

2 3pF

Common-Source Reverse Transfer Capacitance

Crss 0.9 1.5

Equivalent Input Noise Voltage en VDS = 10 V, VGS = 0 V, f = 1 kHz 15 nV/Hz

3

JFET and OpAmp

Special JFET Specifications (TA = 25 °C unless otherwise noted)

© 2001 Vishay Siliconix

4

JFET and OpAmp

3 OpAmp2 – CMOS very low power OpAmp for single and multi color detectors

LME-335, /-337, /-341, /-345, /-351, /-353, /-392, /-553, /-541, /-551; LIM-052, /-054, /-162, /-262; LMM-242, /-244; LFP-3041L-337; LFP-3950-337; LFP-80105-337 Features Single [(4.5 ... 16) V] and split supply [(±2.2 ... ±8) V] operation

Low supply current; very low input bias current

Rail-to-Rail output swing; high voltage gain

Absolute maximum ratings Supply voltage (V+ - V-): 16V

Differential input voltage: ± supply voltage

Voltage at output pin: (V-) -0.3 V ... (V+) +0.3 V

Current at input pin: ±5 mA

Current at output pin: ±30 mA

Current at power supply pin: ±40 mA

Power dissipation: 10 mW

Specifications (TA = 25 °C; V+ = 5 V; V- = -5 V; RL > 1 MΩ unless otherwise noted) Parameter Symbol Test Condition Min Typ Max Unit

Static Input Offset Voltage VOS 200 1500 µVInput Bias Current IB 1 60 pAInput Offset Current IOS 0.5 60 pACommon Mode Rejection Ratio CMRR -5.0 V VIC 2.7 V 75 88 dBInput Common-Mode VoltageRange

VICR -5

to 4-5.3

to 4,2V

Large Signal Voltage Gain AV RL = 1 M 3000 V/mV

RL = 100 k 45 650 V/mV

positive peak Output Swing

negative peak

VO

RL = 1 M to Gnd RL = 100 k to Gnd

4.98

V4,9 4.93

RL = 1 M to Gnd RL = 100 k to Gnd

-4.99 -4.85 -4.91

Supply Current IS VO = 0V, No Load 80 125 µADynamic

Slew Rate SR VO = ± 1.9V, RL = 100 k, CL =100pF

70 120 V/ms

Gain-Bandwidth Product GBW 210 kHzPhase Margin m 63 Deg

Equivalent Input Noise Voltage Vn f = 1 kHz 19 nV/HzEquivalent Input Noise Current In f = 1 kHz 0.6 fA/Hz

5

JFET and OpAmp

OpAmp2 Specifications

10

5

30

025 45 65 85II

Ba

nd

IIO

–In

pu

tB

ias

an

dIn

pu

tO

ffs

et

Cu

rre

nts

–p

A

20

15

25

INPUT BIAS AND INPUT OFFSET CURRENTS†

vsFREE-AIR TEMPERATURE

35

105 125

IIB

IIO

VDD± = ±2.5 VVIC = 0VO = 0RS = 50 Ω

TA – Free-Air Temperature – °C

I IB

I IO

IDD

–S

up

ply

Cu

rre

nt

–u

A

SUPPLY CURRENT†

vsSUPPLY VOLTAGE

| VDD ± | – Supply Voltage – V

I DD

Aµ

120

80

40

00 1 2 3 4 5

160

200

240

6 7 8

TA = 25°C

TA = 125°C

VO = 0No Load

TA = –55°C

TA = –40°C

EQUIVALENT INPUT NOISE VOLTAGEvs

FREQUENCY

f – Frequency – Hz

VN

–E

qu

iva

len

tIn

pu

tN

ois

eV

olt

ag

e–

nv

//H

zn

V/

Hz

Vn

40

20

10

0

60

30

50

101 102 103 104

VDD± = ±5 VRS = 20 ΩTA = 25°C

© 2001 Texas Instruments Incorporated

0.6

0.4

0.2

00 1 2 3

VO

L–

Lo

w-L

ev

elO

utp

utV

olt

ag

e–

V

0.8

1

LOW-LEVEL OUTPUT VOLTAGE‡

vsLOW-LEVEL OUTPUT CURRENT

1.2

4 5

VIC = 0VIC = 1.25 V

VIC = 2.5 V

VDD = 5 VTA = 25°C

V OL

IOL – Low-Level Output Current – mA

VO

H–

Hig

h-L

ev

elO

utp

utV

olt

ag

e–

V

HIGH-LEVEL OUTPUT VOLTAGE†‡

vsHIGH-LEVEL OUTPUT CURRENT

| IOH| – High-Level Output Current – µA

V OH

3

2

1

00 200 400

4

5

600 800

VDD = 5 V

TA = –40°C

TA = 25°C

TA = 125°C

TA = –55°C

Dif

fere

nti

alG

ain

–V

/m

V

DIFFERENTIAL GAIN‡

vsLOAD RESISTANCE

RL – Load Resistance – kΩ

104

103

102

10

1 101 102 103

VO (PP) = 2 VTA = 25°C

VDD = ±5 V

VDD = 5 V

om

–P

ha

se

Ma

rgin

φm

f – Frequency – Hz

LARGE-SIGNAL DIFFERENTIAL VOLTAGEAMPLIFICATION AND PHASE MARGIN†

vsFREQUENCY

AV

D–

La

rge

-Sig

na

lDif

fere

nti

al

AV

D Vo

lta

ge

Am

pli

fic

ati

on

–d

B

20

80

60

40

0

–20

–40103 104 105 106 107

180°

135°

90°

45°

0°

–45°

–90°

Gain

VDD = 5 VRL = 50 kΩCL= 100 pFTA = 25°C

Phase Margin

om

–P

ha

se

Ma

rgin

PHASE MARGINvs

LOAD CAPACITANCE

CL – Load Capacitance – pF

mφ

101 102 103 105

75°

60°

45°

30°

15°

0°

Rnull = 200 Ω

Rnull = 500 Ω

Rnull = 50 Ω

Rnull = 0

TA = 25°C

Rnull = 10 Ω

104

50 kΩ

50 kΩ

VDD –

VDD+Rnull

CL

VI+–

Rnull = 100 Ω

Ga

inM

arg

in–

dB

GAIN MARGINvs

LOAD CAPACITANCE

CL – Load Capacitance – pF

20

10

5

0

15

101 102 103 105

Rnull = 100 Ω

TA = 25°C

Rnull = 50 Ω

104

Rnull = 500 Ω

Rnull = 200 Ω

Rnull = 0

Rnull = 10 Ω

6

JFET and OpAmp

4 OpAmp3 – CMOS very low power OpAmp for use in single supply detectors and low current detectors

LME-336, /-346, /-352, LIE-235, /-241, /-245, /-251 Features Single supply [(2.7 ... 10) V] operation and split supply [(±1.35 … ±5) V] operation

Ultra Low supply current; low input bias current

Rail-to-Rail output swing; high voltage gain

Absolute maximum ratings Single-Supply voltage (V+ - V-/GND): 10V

Differential input voltage: ± supply voltage

Voltage at output pin: (V-) -0.3 V ... (V+) +0.3 V

Current at output pin: ±50 mA

Current at power supply pin: ±50 mA

Power dissipation: 10 mW (RL≥10kOhm)

Specifications (TA = 25 °C; V+ = 3 V; V- = 0 V; RL > 10 kΩ unless otherwise noted)

Parameter Symbol Test Condition Min Typ Max UnitStatic

Input Offset Voltage VOS 0.47 3 mVInput Bias Current IB 1 60 pAInput Offset Current IOS 0.5 60 pACommon Mode Rejection Ratio CMRR 0.0 V VIC 1.7 V 65 83 dBInput Common-Mode Voltage Range

VICR 0

to 20

to 2,2 V

Large Signal Voltage Gain AV RL = 1 M 600 V/mV

RL = 10 k 3 7 V/mV

positive peak Output Swing

negative peak

VO

RL = 1 M to Gnd RL = 10 k to Gnd

2.94

V2.85

RL = 1 Mto V+ RL = 10 k to V+

0.015 0,15

Supply Current IS VO = +1.5 V, No load 11 25 µADynamic

Slew Rate SR VO = 1.1 to 1.9V (RL = 10 k, CL =100pF to 1.5V)

10 25 V/ms

Gain-Bandwidth Product GBW 56 kHzPhase Margin m 56 DegEquivalent Input Noise Voltage Vn f = 1 kHz 22 nV/√HzEquivalent Input Noise Current In f = 1 kHz 0.6 fA/√Hz

7

JFET and OpAmp

OpAmp3 Specifications

IIB

an

dII

O–

Inp

ut

Bia

sa

nd

Inp

ut

Off

se

tC

urr

en

ts–

pA

INPUT BIAS AND INPUT OFFSET CURRENTS†

vsFREE-AIR TEMPERATURE

I IB

I IO

TA – Free-Air Temperature – °C

50

40

20

10

0

90

30

25 45 65 85

70

60

80

100

105 125

IIB

IIO

VDD± = ±2.5 VVIC = 0VO = 0RS = 50 Ω

–H

igh

-Le

ve

lOu

tpu

tVo

lta

ge

–V

HIGH-LEVEL OUTPUT VOLTAGE†‡

vsHIGH-LEVEL OUTPUT CURRENT

V OH

| IOH | – High-Level Output Current – µA

2

1.5

1

00 200 400

2.5

3

600 800

VDD = 3 V

TA = –40°C

0.5

TA = 25°C

TA = 85°C

TA = 125°C

–L

ow

-Lev

elO

utp

utV

olt

ag

e–

V

LOW-LEVEL OUTPUT VOLTAGE†‡

vsLOW-LEVEL OUTPUT CURRENT

V OL

IOL – Low-Level Output Current – mA

0.4

0.2

1.2

00 1 2 3

0.8

0.6

1

1.4

4 5

TA = 85°C

TA = – 40°C

TA = 25°C

TA = 125°C

VDD = 3 VVIC = 1.5 V

© 2001 Texas Instruments Incorporated

–M

ax

imu

mP

ea

k-t

o-P

ea

kO

utp

utV

olt

ag

e–

V

f – Frequency – Hz

MAXIMUM PEAK-TO-PEAK OUTPUT VOLTAGE‡

vsFREQUENCY

VO

(PP

)

4

2

1

5

3

0

RI = 10 kΩTA = 25°C

VDD = 5 V

VDD = 3 V

102 103 104

–S

ho

rt-C

irc

uit

Ou

tpu

tCu

rre

nt

–m

A

SHORT-CIRCUIT OUTPUT CURRENTvs

SUPPLY VOLTAGE

I OS

VDD – Supply Voltage – V

10

6

2

2 3 4 5

14

16

6 7 8

12

8

4

0

–2

VID = –100 mV

VID = 100 mV

VO = VDD/2VIC = VDD/2TA = 25°C

LARGE-SIGNAL DIFFERENTIALVOLTAGE AMPLIFICATION†‡

vsFREE-AIR TEMPERATURE

TA – Free-Air Temperature – °C

–L

arg

e-S

ign

alD

iffe

ren

tia

lVo

lta

ge

AV

DA

mp

lifi

ca

tio

n–

V/m

V

– 50 –25 0 25 50 75 100

RL = 10 kΩ

RL = 1 MΩ

103

102

101

1

VDD = 3 VVIC = 1.5 VVO = 0.5 V to 2.5 V

52157–

–E

qu

ival

entI

np

utN

ois

eV

olt

age

–

f – Frequency – Hz

EQUIVALENT INPUT NOISE VOLTAGE†

vsFREQUENCY

Vn

nV

/H

z

40

30

20

0

60

50

10

VDD = 3 VRS = 20 ΩTA = 25°C

70

80

101 102 103 104

–S

up

ply

Cu

rren

t–

Aµ

I DD

VDD – Supply Voltage – V

SUPPLY CURRENT†

vsSUPPLY VOLTAGE

VO = VDD/2VIC = VDD/2No Load

TA = 25°C

TA = 85°C

TA = –40°C

15

10

5

0 2 4 6

20

25

30

8 100

–U

nit

y-G

ain

Ba

nd

wid

th–

kH

z

UNITY-GAIN BANDWIDTHvs

LOAD CAPACITANCE

CL – Load Capacitance – pF

B1

60

10

40

0

80

50

70

20

30

101 102 103 104 105

TA = 25°C

106

8