LT6236/LT6237/LT6238
1
623637fb
For more information www.linear.com/LT6236
Typical applicaTion
FeaTures DescripTion
Rail-to-Rail Output
215MHz, 1.1nV/√Hz
Op Amp/SAR ADC Driver
The LT
®
6236/LT6237/LT6238 are single/dual/quad low
noise, rail-to-rail output op amps that feature 1.1nV/√Hz
input referred noise voltage density and draw only 3.5mA
of supply current per amplifier. These amplifiers combine
very low noise and supply current with a 215MHz gain
bandwidth product and a 70V/µs slew rate. Low noise, fast
settling time and low offset voltage make this amplifier
optimal to drive low noise, high speed SAR ADCs. The
LT6236 includes a shutdown feature that can be used to
reduce the supply current to less than 10µA.
This amplifier family has an output that swings within
50mV of either supply rail to maximize the signal dynamic
range in low supply applications and is specified on 3.3V,
5V and ±5V supplies.
The LT6236/LT6237/LT6238 are upgrades to the LT6230/
LT6231/LT6232, offering similar performance with reduced
wideband noise beyond 100kHz.
Differentially Driving a SAR ADC LT6237 Driving LTC2389-18 fIN = 2kHz,
–1dBFS, 32768-Point FFT
applicaTions
n Low Noise: 1.1nV/√Hz
n Low Supply Current: 3.5mA/Amp Max
n Low Offset Voltage: 350µV Max
n Fast Settling Time: 570ns to 18-Bit, 2VP-P Output
n Low Distortion: THD = –116.8dB at 2kHz
n Wide Supply Range: 3V to 12.6V
n Output Swings Rail-to-Rail
n 215MHz Gain-Bandwidth Product
n Specified Temperature Range: –40°C to 125°C
n LT6236 Shutdown to 10µA Max
n LT6236 in Low Profile (1mm) ThinSOT™ Package
n Dual LT6237 in 3mm × 3mm 8-Lead DFN and 8-Lead
MSOP Packages
n LT6238 in 16-Lead SSOP Package
n 16-Bit and 18-Bit SAR ADC Drivers
n Active Filters
n Low Noise, Low Power Signal Processing
L, LT, LTC , LT M, Linear Technology and the Linear logo are registered trademarks and
ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property
of their respective owners.
623637 TA01a
IN–
IN–
IN+
IN+
VS+= 6V
270pF
38.3Ω
38.3Ω
LOWPASS FILTERS
LTC2389-18
270pF 49.9Ω
49.9Ω
18-BIT
2.5Msps
–
+
+
–
1/2 LT6237
1/2 LT6237
VS–= –2V
FREQUENCY (MHz)
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1
AMPLITUDE (dBFS)
62367 TA01b
0
–150
–140
–130
–120
–110
–100
–90
–80
–70
–60
–50
–40
–30
–20
–10
1.2
VOUT = 7.3VP-P
HD2 = –129.5dBc
HD3 = –118.7dBc
SFDR = 117.7dB
THD = –116.8dB
SNR = 99.7dB
SINAD = 98.9dB
LT6236/LT6237/LT6238
2
623637fb
For more information www.linear.com/LT6236
pin conFiguraTion
absoluTe MaxiMuM raTings
Total Supply Voltage (V+ to V–) .............................. 12.6V
Input Current (Note 2) ......................................... ±40mA
Output Short-Circuit Duration (Note 3) ............ Indefinite
Operating Temperature Range (Note 4).. –40°C to 125°C
(Note 1)
1
2
3
6
5
4
TOP VIEW
S6 PACKAGE
6-LEAD PLASTIC TSOT-23
V+
ENABLE
–IN
OUT
V–
+IN
TJMAX = 150°C, θJA = 192°C/W
TOP VIEW
DD PACKAGE
8-LEAD (3mm × 3mm) PLASTIC DFN
5
6
7
8
9
4
3
2
1OUT A
–IN A
+IN A
V–
V+
OUT B
–IN B
+IN B
TJMAX = 150°C, θJA = 43°C/W
UNDERSIDE METAL CONNECTED TO V–
(PCB CONNECTION OPTIONAL)
1
2
3
4
OUT A
–IN A
+IN A
V–
8
7
6
5
V+
OUT B
–IN B
+IN B
TOP VIEW
MS8 PACKAGE
8-LEAD PLASTIC MSOP
TJMAX = 150°C, θJA = 273°C/W
GN PACKAGE
16-LEAD NARROW PLASTIC SSOP
1
2
3
4
5
6
7
8
TOP VIEW
16
15
14
13
12
11
10
9
OUT A
–IN A
+IN A
V+
+IN B
–IN B
OUT B
NC
OUT D
–IN D
+IN D
V–
+IN C
–IN C
OUT C
NC
+
–
+
–B C
+
–
+
–
A D
TJMAX = 150°C, θJA = 110°C/W
orDer inForMaTion
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION
SPECIFIED
TEMPERATURE RANGE
LT6236CS6#TRMPBF LT6236CS6#TRPBF LTGHM 6-Lead Plastic TSOT-23 0°C to 70°C
LT6236IS6#TRMPBF LT6236IS6#TRPBF LTGHM 6-Lead Plastic TSOT-23 –40°C to 85°C
LT6236HS6#TRMPBF LT6236HS6#TRPBF LTGHM 6-Lead Plastic TSOT-23 –40°C to 125°C
LT6237CDD#PBF LT6237CDD#TRPBF LGHN 8-Lead (3mm × 3mm) Plastic DFN 0°C to 70°C
LT6237IDD#PBF LT6237IDD#TRPBF LGHN 8-Lead (3mm × 3mm) Plastic DFN –40°C to 85°C
LT6237HDD#PBF LT6237HDD#TRPBF LGHN 8-Lead (3mm × 3mm) Plastic DFN –40°C to 125°C
LT6237CMS8#PBF LT6237CMS8#TRPBF LTGHP 8-Lead Plastic MSOP 0°C to 70°C
LT6237IMS8#PBF LT6237IMS8#TRPBF LTGHP 8-Lead Plastic MSOP –40°C to 85°C
LT6237HMS8#PBF LT6237HMS8#TRPBF LTGHP 8-Lead Plastic MSOP –40°C to 125°C
LT6238CGN#PBF LT6238CGN#TRPBF 6238 16-Lead Narrow Plastic SSOP 0°C to 70°C
LT6238IGN#PBF LT6238IGN#TRPBF 6238 16-Lead Narrow Plastic SSOP –40°C to 85°C
LT6238HGN#PBF LT6238HGN#TRPBF 6238 16-Lead Narrow Plastic SSOP –40°C to 125°C
TRM = 500 pieces. *Temperature grades are identified by a label on the shipping container.
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
Specified Temperature Range (Note 5).....–40°C to125°C
Maximum Junction Temperature .......................... 150°C
Storage Temperature Range .................. –65°C to 150°C
LT6236/LT6237/LT6238
3
623637fb
For more information www.linear.com/LT6236
elecTrical characTerisTics
TA = 25°C, VS = 5V, 0V; VS = 3.3V, 0V; VCM = VOUT = half supply,
ENABLE = 0V, unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNIT
VOS Input Offset Voltage LT6236
LT6237MS8, LT6238GN
LT6237DD8
100
50
75
500
350
450
µV
µV
µV
Input Offset Voltage Match
(Channel-to-Channel) (Note 6) 100 600 µV
IBInput Bias Current 5 10 µA
IB Match (Channel-to-Channel) (Note 6) 0.1 0.9 µA
IOS Input Offset Current 0.1 0.6 µA
Input Noise Voltage 0.1Hz to 10Hz 180 nVP-P
enInput Noise Voltage Density f = 10kHz, VS = 5V 1.1 1.7 nV/√Hz
inInput Noise Current Density, Balanced Source
Input Noise Current Density, Unbalanced Source f = 10kHz, VS = 5V, RS = 10k
f = 10kHz, VS = 5V, RS = 10k 1
2.4 pA/√Hz
pA/√Hz
RIN Input Resistance Common Mode
Differential Mode 6.5
7.5 MΩ
kΩ
CIN Input Capacitance Common Mode
Differential Mode 2.9
7.7 pF
pF
AVOL Large-Signal Gain VS = 5V, VO = 0.5V to 4.5V, RL = 10k to VS/2
VS = 5V, VO = 0.5V to 4.5V, RL = 1k to VS/2
VS = 5V, VO = 1V to 4V, RL = 100Ω to VS/2
105
21
5.4
200
40
9
V/mV
V/mV
V/mV
VS = 3.3V, VO = 0.65V to 2.65V, RL = 10k to VS/2
VS = 3.3V, VO = 0.65V to 2.65V, RL = 1k to VS/2 90
16.5 175
32 V/mV
V/mV
VCM Input Voltage Range Guaranteed by CMRR, VS = 5V, 0V
Guaranteed by CMRR, VS = 3.3V, 0V 1.5
1.15 4
2.65 V
V
CMRR Common Mode Rejection Ratio VS = 5V, VCM = 1.5V to 4V
VS = 3.3V, VCM = 1.15V to 2.65V 90
90 115
115 dB
dB
PSRR Power Supply Rejection Ratio VS = 3V to 10V 90 115 dB
Minimum Supply Voltage (Note 7) 3 V
VOL Output Voltage Swing Low (Note 8) No Load
ISINK = 5mA
VS = 5V, ISINK = 20mA
VS = 3.3V, ISINK = 15mA
4
85
240
185
40
190
460
350
mV
mV
mV
mV
VOH Output Voltage Swing High (Note 8) No Load
ISOURCE = 5mA
VS = 5V, ISOURCE = 20mA
VS = 3.3V, ISOURCE = 15mA
5
90
325
250
50
200
600
400
mV
mV
mV
mV
ISC Short-Circuit Current VS = 5V
VS = 3.3V ±30
±25 ±45
±40 mA
mA
ISSupply Current per Amplifier
Disabled Supply Current per Amplifier
ENABLE = V+ – 0.35V 3.15
0.2 3.5
10 mA
µA
IENABLE ENABLE Pin Current ENABLE = 0.3V –25 –75 µA
LT6236/LT6237/LT6238
4
623637fb
For more information www.linear.com/LT6236
elecTrical characTerisTics
TA = 25°C, VS = 5V, 0V; VS = 3.3V, 0V; VCM = VOUT = half supply,
ENABLE = 0V, unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNIT
VLENABLE Pin Input Voltage Low 0.3 V
VHENABLE Pin Input Voltage High V+ – 0.35V V
Output Leakage Current ENABLE = V+ – 0.35V, VO = 1.5V to 3.5V 0.2 10 µA
tON Turn-On Time ENABLE = 5V to 0V, RL = 1k, VS = 5V 800 ns
tOFF Turn-Off Time ENABLE = 0V to 5V, RL = 1k, VS = 5V 41 µs
GBW Gain-Bandwidth Product Frequency = 1MHz, VS = 5V 200 MHz
f–3db –3dB Bandwidth VS = 5V, RL = 100Ω 90 MHz
SR Slew Rate VS = 5V, A
V = –1, RL = 1k, VO = 1.5V to 3.5V 42 60 V/µs
FPBW Full-Power Bandwidth VS = 5V, VOUT = 3VP-P (Note 9) 4.4 6.3 MHz
tSSettling Time 0.1%, VS = 5V, VSTEP = 2V, AV = 1
0.01%
0.0015% (16-Bit)
4ppm (18-Bit)
50
60
240
570
ns
ns
ns
ns
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNIT
VOS Input Offset Voltage LT6236
LT6237MS8, LT6238GN
LT6237DD8
l
l
l
600
450
550
µV
µV
µV
Input Offset Voltage Match
(Channel-to-Channel) (Note 6)
l800 µV
VOS TC Input Offset Voltage Drift (Note 10) LT6236
LT6237MS8
LT6237DD8
LT6238GN
l
l
l
l
0.5
0.3
0.4
0.5
2.0
1.4
2.2
2.2
µV/°C
µV/°C
µV/°C
µV/°C
IBInput Bias Current l11 µA
IB Match (Channel-to-Channel) (Note 6) l1 µA
IOS Input Offset Current l0.7 µA
AVOL Large-Signal Gain VS = 5V, VO = 0.5V to 4.5V, RL = 10k to VS/2
VS = 5V, VO = 0.5V to 4.5V, RL = 1k to VS/2
VS = 5V, VO = 1V to 4V, RL = 100Ω to VS/2
l
l
l
78
17
4.1
V/mV
V/mV
V/mV
VS = 3.3V, VO = 0.65V to 2.65V, RL = 10k to VS/2
VS = 3.3V, VO = 0.65V to 2.65V, RL = 1k to VS/2
l
l
66
13 V/mV
V/mV
VCM Input Voltage Range Guaranteed by CMRR
VS = 5V, 0V
Vs = 3.3V, 0V
l
l
1.5
1.15
4
2.65
V
V
CMRR Common Mode Rejection Ratio VS = 5V, VCM = 1.5V to 4V
VS = 3.3V, VCM = 1.15V to 2.65V
l
l
90
85 dB
dB
PSRR Power Supply Rejection Ratio VS = 3V to 10V l85 dB
Minimum Supply Voltage (Note 7) l3 V
VOL Output Voltage Swing Low (Note 8) No Load
ISINK = 5mA
VS = 5V, ISINK = 20mA
VS = 3.3V, ISINK = 15mA
l
l
l
l
50
200
500
380
mV
mV
mV
mV
The l denotes the specifications which apply over the 0°C < TA < 70°C temperature range. VS = 5V, 0V; VS = 3.3V, 0V; VCM = VOUT =
half supply, ENABLE = 0V, unless otherwise noted.
LT6236/LT6237/LT6238
5
623637fb
For more information www.linear.com/LT6236
elecTrical characTerisTics
The l denotes the specifications which apply over the 0°C < TA < 70°C
temperature range. VS = 5V, 0V; VS = 3.3V, 0V; VCM = VOUT = half supply, ENABLE = 0V, unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNIT
VOH Output Voltage Swing High (Note 8) No Load
ISOURCE = 5mA
VS = 5V, ISOURCE = 20mA
VS = 3.3V, ISOURCE = 15mA
l
l
l
l
60
215
650
430
mV
mV
mV
mV
ISC Short-Circuit Current VS = 5V
VS = 3.3V
l
l
±25
±20 mA
mA
ISSupply Current per Amplifier
Disabled Supply Current per Amplifier
ENABLE = V+ – 0.25V
l
l
14.2 mA
µA
IENABLE ENABLE Pin Current ENABLE = 0.3V l–85 µA
VLENABLE Pin Input Voltage Low l0.3 V
VHENABLE Pin Input Voltage High lV+ – 0.25V V
SR Slew Rate VS = 5V, AV = –1, RL = 1k, VO = 1.5V to 3.5V l35 V/µs
FPBW Full-Power Bandwidth (Note 9) VS = 5V, VOUT = 3VP-P l3.7 MHz
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VOS Input Offset Voltage LT6236
LT6237MS8, LT6238GN
LT6237DD8
l
l
l
700
550
650
µV
µV
µV
Input Offset Voltage Match
(Channel-to-Channel) (Note 6)
l1000 µV
VOS TC Input Offset Voltage Drift (Note 10) LT6236
LT6237MS8
LT6237DD8
LT6238GN
l
l
l
l
0.5
0.3
0.4
0.5
2.0
1.4
2.2
2.2
µV/°C
µV/°C
µV/°C
µV/°C
IBInput Bias Current l12 µA
IB Match (Channel-to-Channel) (Note 6) l1.1 µA
IOS Input Offset Current l0.8 µA
AVOL Large-Signal Gain VS = 5V, VO = 0.5V to 4.5V, RL = 10k to VS/2
VS = 5V, VO = 0.5V to 4.5V, RL = 1k to VS/2
VS = 5V, VO = 1V to 4V, RL = 100Ω to VS/2
l
l
l
72
16
3.6
V/mV
V/mV
V/mV
VS = 3.3V, VO = 0.65V to 2.65V, RL = 10k to VS/2
VS = 3.3V, VO = 0.65V to 2.65V, RL = 1k to VS/2
l
l
60
12 V/mV
V/mV
VCM Input Voltage Range Guaranteed by CMRR
VS = 5V, 0V
VS = 3.3V, 0V
l
l
1.5
1.15
4
2.65
V
V
CMRR Common Mode Rejection Ratio VS = 5V, VCM = 1.5V to 4V
VS = 3.3V, VCM = 1.15V to 2.65V
l
l
90
85 dB
dB
PSRR Power Supply Rejection Ratio VS = 3V to 10V l85 dB
Minimum Supply Voltage (Note 7) l3 V
VOL Output Voltage Swing Low (Note 8) No Load
ISINK = 5mA
VS = 5V, ISINK = 15mA
VS = 3.3V, ISINK = 15mA
l
l
l
l
60
210
510
390
mV
mV
mV
mV
The l denotes the specifications which apply over the –40°C < TA < 85°C temperature range. VS = 5V, 0V; VS = 3.3V, 0V; VCM = VOUT =
half supply, ENABLE = 0V, unless otherwise noted. (Note 5)
LT6236/LT6237/LT6238
6
623637fb
For more information www.linear.com/LT6236
elecTrical characTerisTics
The l denotes the specifications which apply over the –40°C < TA < 85°C
temperature range. VS = 5V, 0V; VS = 3.3V, 0V; VCM = VOUT = half supply, ENABLE = 0V, unless otherwise noted. (Note 5)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VOS Input Offset Voltage LT6236
LT6237MS8,LT6238GN
LT6237DD8
l
l
l
750
650
700
µV
µV
µV
Input Offset Voltage Match
(Channel-to-Channel) (Note 6)
l1000 µV
VOS TC Input Offset Voltage Drift (Note 10) LT6236
LT6237MS8
LT6237DD8
LT6238GN
l
l
l
l
0.5
0.3
0.4
0.5
2.0
1.4
2.2
2.2
µV/°C
µV/°C
µV/°C
µV/°C
IBInput Bias Current l12 µA
IB Match (Channel-to-Channel) (Note 6) l1.1 µA
IOS Input Offset Current l1.2 µA
AVOL Large-Signal Gain VS = 5V, VO = 0.5V to 4.5V, RL = 10k to VS/2
VS = 5V, VO = 0.5V to 4.5V, RL = 1k to VS/2
VS = 5V, VO = 1V to 4V, RL = 100Ω to VS/2
l
l
l
62
14
3
V/mV
V/mV
V/mV
VS = 3.3V, VO = 0.65V to 2.65V, RL = 10k to VS/2
VS = 3.3V, VO = 0.65V to 2.65V, RL = 1k to VS/2
l
l
52
11 V/mV
V/mV
VCM Input Voltage Range Guaranteed by CMRR
VS = 5V, 0V
VS = 3.3V, 0V
l
l
1.5
1.15
4
2.65
V
V
CMRR Common Mode Rejection Ratio VS = 5V, VCM = 1.5V to 4V
VS = 3.3V, VCM = 1.15V to 2.65V
l
l
90
85 dB
dB
PSRR Power Supply Rejection Ratio VS = 3V to 10V l85 dB
Minimum Supply Voltage (Note 7) l3 V
VOL Output Voltage Swing Low (Note 8) No Load
ISINK = 5mA
VS = 5V, ISINK = 15mA
VS = 3.3V, ISINK = 15mA
l
l
l
l
60
225
550
425
mV
mV
mV
mV
VOH Output Voltage Swing High (Note 8) No Load
ISOURCE = 5mA
VS = 5V, ISOURCE = 20mA
VS = 3.3V, ISOURCE = 15mA
l
l
l
l
80
240
700
470
mV
mV
mV
mV
VOH Output Voltage Swing High (Note 6) No Load
ISOURCE = 5mA
VS = 5V, ISOURCE = 20mA
VS = 3.3V, ISOURCE = 15mA
l
l
l
l
70
220
675
440
mV
mV
mV
mV
ISC Short-Circuit Current VS = 5V
VS = 3.3V
l
l
±15
±15 mA
mA
ISSupply Current per Amplifier
Disabled Supply Current per Amplifier
ENABLE = V+ – 0.2V
l
l
14.4 mA
µA
IENABLE ENABLE Pin Current ENABLE = 0.3V l–100 µA
VLENABLE Pin Input Voltage Low l0.3 V
VHENABLE Pin Input Voltage High lV+ – 0.2V V
SR Slew Rate VS = 5V, AV = –1, RL = 1k, VO = 1.5V to 3.5V l31 V/µs
FPBW Full-Power Bandwidth (Note 9) VS = 5V, VOUT = 3VP-P l3.3 MHz
The l denotes the specifications which apply over the –40°C < TA < 125°C temperature range. VS = 5V, 0V; VS = 3.3V, 0V; VCM = VOUT
= half supply, ENABLE = 0V, unless otherwise noted. (Note 5)
LT6236/LT6237/LT6238
7
623637fb
For more information www.linear.com/LT6236
elecTrical characTerisTics
The l denotes the specifications which apply over the –40°C < TA < 125°C
temperature range. VS = 5V, 0V; VS = 3.3V, 0V; VCM = VOUT = half supply, ENABLE = 0V, unless otherwise noted. (Note 5)
ISC Short-Circuit Current VS = 5V
VS = 3.3V
l
l
±15
±15 mA
mA
ISSupply Current per Amplifier
Disabled Supply Current per Amplifier
ENABLE = V+ – 0.15V
l
l
25 mA
µA
IENABLE ENABLE Pin Current ENABLE = 0.3V l–100 µA
VLENABLE Pin Input Voltage Low l0.3 V
VHENABLE Pin Input Voltage High lV+ – 0.15V V
SR Slew Rate VS = 5V, AV = –1, RL = 1k, VO = 1.5V to 3.5V l31 V/µs
FPBW Full-Power Bandwidth (Note 9) VS = 5V, VOUT = 3VP-P l3.3 MHz
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VOS Input Offset Voltage LT6236
LT6237MS8, LT6238GN
LT6237DD8
100
50
75
500
350
450
µV
µV
µV
Input Offset Voltage Match
(Channel-to-Channel) (Note 6) 100 600 µV
IBInput Bias Current 5 10 µA
IB Match (Channel-to-Channel) (Note 6) 0.1 0.9 µA
IOS Input Offset Current 0.1 0.6 µA
Input Noise Voltage 0.1Hz to 10Hz 180 nVP-P
enInput Noise Voltage Density f = 10kHz 1.1 1.7 nV/√Hz
inInput Noise Current Density, Balanced Source
Input Noise Current Density, Unbalanced source f = 10kHz, RS = 10k
f = 10kHz, RS = 10k 1
2.4 pA/√Hz
pA/√Hz
RIN Input Resistance Common Mode
Differential Mode 6.5
7.5 MΩ
kΩ
CIN Input Capacitance Common Mode
Differential Mode 2.4
6.5 pF
pF
AVOL Large-Signal Gain VO = ±4.5V, RL = 10k
VO = ±4.5V, RL = 1k
VO = ±2V, RL = 100Ω
140
35
8.5
260
65
16
V/mV
V/mV
V/mV
VCM Input Voltage Range Guaranteed by CMRR –3 4 V
CMRR Common Mode Rejection Ratio VCM = –3V to 4V 95 120 dB
PSRR Power Supply Rejection Ratio VS = ±1.5V to ±5V 90 115 dB
VOL Output Voltage Swing Low (Note 8) No Load
ISINK = 5mA
ISINK = 20mA
4
85
240
40
190
460
mV
mV
mV
VOH Output Voltage Swing High (Note 8) No Load
ISOURCE = 5mA
ISOURCE = 20mA
5
90
325
50
200
600
mV
mV
mV
ISC Short-Circuit Current ±30 mA
ISSupply Current per Amplifier
Disabled Supply Current per Amplifier
ENABLE = 4.65V 3.3
0.2 3.9 mA
µA
IENABLE ENABLE Pin Current ENABLE = 0.3V –35 –85 µA
VLENABLE Pin Input Voltage Low 0.3 V
VHENABLE Pin Input Voltage High 4.65 V
TA = 25°C, VS = ±5V, VCM = VOUT = 0V, ENABLE = 0V, unless otherwise noted.
LT6236/LT6237/LT6238
8
623637fb
For more information www.linear.com/LT6236
TA = 25°C, VS = ±5V, VCM = VOUT = 0V, ENABLE = 0V, unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VOS Input Offset Voltage LT6236
LT6237MS8, LT6238GN
LT6237DD8
l
l
l
600
450
550
µV
µV
µV
Input Offset Voltage Match
(Channel-to-Channel) (Note 6)
l800 µV
VOS TC Input Offset Voltage Drift (Note 10) LT6236
LT6237MS8
LT6237DD8
LT6238GN
l
l
l
l
0.7
0.5
0.4
0.5
2.2
1.8
2.2
2.2
µV/°C
µV/°C
µV/°C
µV/°C
IBInput Bias Current l11 µA
IB Match (Channel-to-Channel) (Note 6) l1 µA
IOS Input Offset Current l0.7 µA
AVOL Large-Signal Gain VO = ±4.5V, RL = 10k
VO = ±4.5V, RL = 1k
VO = ±2V, RL = 100Ω
l
l
l
100
27
6
V/mV
V/mV
V/mV
VCM Input Voltage Range Guaranteed by CMRR l–3 4 V
CMRR Common Mode Rejection Ratio VCM = –3V to 4V l95 dB
PSRR Power Supply Rejection Ratio VS = ±1.5V to ±5V l85 dB
VOL Output Voltage Swing Low (Note 8) No Load
ISINK = 5mA
ISINK = 20mA
l
l
l
50
200
500
mV
mV
mV
VOH Output Voltage Swing High (Note 8) No Load
ISOURCE = 5mA
ISOURCE = 20mA
l
l
l
60
215
650
mV
mV
mV
ISC Short-Circuit Current l±25 mA
ISSupply Current per Amplifier
Disabled Supply Current per Amplifier
ENABLE = 4.75V
l
l
14.6 mA
µA
IENABLE ENABLE Pin Current ENABLE = 0.3V l–95 µA
VLENABLE Pin Input Voltage Low l0.3 V
VHENABLE Pin Input Voltage High l4.75 V
SR Slew Rate AV = –1, RL = 1k, VO = –2V to 2V l44 V/µs
FPBW Full-Power Bandwidth VOUT = 3VP-P (Note 9) l4.66 MHz
elecTrical characTerisTics
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Output Leakage Current ENABLE = V+ –0.35V, VO = ±1V 0.2 10 µA
tON Turn-On Time ENABLE = 5V to 0V, RL = 1k 800 ns
tOFF Turn-Off Time ENABLE = 0V to 5V, RL = 1k 62 µs
GBW Gain-Bandwidth Product Frequency = 1MHz 150 215 MHz
SR Slew Rate AV = –1, RL = 1k, VO = –2V to 2V 50 70 V/µs
FPBW Full-Power Bandwidth VOUT = 3VP-P (Note 9) 5.3 7.4 MHz
tSSettling Time 0.1%, VSTEP = 4V, AV = 1,
0.01%
0.0015% (16-Bit)
4ppm (18-Bit)
60
80
470
1200
ns
ns
ns
ns
The l denotes the specifications which apply over the 0°C < TA < 70°C temperature range. VS = ±5V, VCM = VOUT = 0V, ENABLE = 0V,
unless otherwise noted.
LT6236/LT6237/LT6238
9
623637fb
For more information www.linear.com/LT6236
elecTrical characTerisTics
The l denotes the specifications which apply over the –40°C < TA < 85°C
temperature range. VS = ±5V, VCM = VOUT = 0V, ENABLE = 0V, unless otherwise noted. (Note 5)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VOS Input Offset Voltage LT6236
LT6237MS8, LT6238GN
LT6237DD8
l
l
l
700
550
650
µV
µV
µV
Input Offset Voltage Match
(Channel-to-Channel) (Note 6)
l1000 µV
VOS TC Input Offset Voltage Drift (Note 10) LT6236
LT6237MS8
LT6237DD8
LT6238GN
l
l
l
l
0.7
0.5
0.4
0.5
2.2
1.8
2.2
2.2
µV/°C
µV/°C
µV/°C
µV/°C
IBInput Bias Current l12 µA
IB Match (Channel-to-Channel) (Note 6) l1.1 µA
IOS Input Offset Current l0.8 µA
AVOL Large-Signal Gain VO = ±4.5V, RL = 10k
VO = ±4.5V, RL = 1k
VO = ±1.5V, RL = 100Ω
l
l
l
93
25
4.8
V/mV
V/mV
V/mV
VCM Input Voltage Range Guaranteed by CMRR l–3 4 V
CMRR Common Mode Rejection Ratio VCM = –3V to 4V l95 dB
PSRR Power Supply Rejection Ratio VS = ±1.5V to ±5V l85 dB
VOL Output Voltage Swing Low (Note 8) No Load
ISINK = 5mA
ISINK = 15mA
l
l
l
60
210
510
mV
mV
mV
VOH Output Voltage Swing High (Note 8) No Load
ISOURCE = 5mA
ISOURCE = 20mA
l
l
l
70
220
675
mV
mV
mV
ISC Short-Circuit Current l±15 mA
ISSupply Current per Amplifier
Disabled Supply Current per Amplifier
ENABLE = 4.8V
l
l
14.85 mA
µA
IENABLE ENABLE Pin Current ENABLE = 0.3V l–110 µA
VLENABLE Pin Input Voltage Low l0.3 V
VHENABLE Pin Input Voltage High l4.8 V
SR Slew Rate AV = –1, RL = 1k, VO = –2V to 2V l37 V/µs
FPBW Full-Power Bandwidth VOUT = 3VP-P (Note 9) l3.9 MHz
LT6236/LT6237/LT6238
10
623637fb
For more information www.linear.com/LT6236
elecTrical characTerisTics
The l denotes the specifications which apply over the –40°C < TA < 125°C
temperature range. VS = ±5V, VCM = VOUT = 0V, ENABLE = 0V, unless otherwise noted. (Note 5)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VOS Input Offset Voltage LT6236
LT6237MS8, LT6238GN
LT6237DD8
l
l
l
750
650
700
µV
µV
µV
Input Offset Voltage Match
(Channel-to-Channel) (Note 6)
l1000 µV
VOSTC Input Offset Voltage Drift (Note 10) LT6236
LT6237MS8
LT6237DD8
LT6238GN
l
l
l
l
0.7
0.5
0.4
0.5
2.2
1.8
2.2
2.2
µV/°C
µV/°C
µV/°C
µV/°C
IBInput Bias Current l12 µA
IB Match (Channel-to-Channel) (Note 6) l1.1 µA
IOS Input Offset Current l1.2 µA
AVOL Large-Signal Gain VO = ±4.5V, RL = 10k
VO = ±4.5V, RL = 1k
VO = ±1.5V, RL = 100Ω
l
l
l
76
21
4.1
V/mV
V/mV
V/mV
VCM Input Voltage Range Guaranteed by CMRR l–3 4 V
CMRR Common Mode Rejection Ratio VCM = –3V to 4V l95 dB
PSRR Power Supply Rejection Ratio VS = ±1.5V to ±5V l85 dB
VOL Output Voltage Swing Low (Note 8) No Load
ISINK = 5mA
ISINK = 15mA
l
l
l
70
230
550
mV
mV
mV
VOH Output Voltage Swing High (Note 8) No Load
ISOURCE = 5mA
ISOURCE = 20mA
l
l
l
78
240
710
mV
mV
mV
ISC Short-Circuit Current l±15 mA
ISSupply Current per Amplifier
Disabled Supply Current per Amplifier
ENABLE = 4.85V
l
l
10 5.5 mA
µA
IENABLE ENABLE Pin Current ENABLE = 0.3V l–110 µA
VLENABLE Pin Input Voltage Low l0.3 V
VHENABLE Pin Input Voltage High l4.85 V
SR Slew Rate AV = –1, RL = 1k, VO = –2V to 2V l37 V/µs
FPBW Full-Power Bandwidth VOUT = 3VP-P (Note 9) l3.9 MHz
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: Inputs are protected by back-to-back diodes. If the differential
input voltage exceeds 0.7V, the input current must be limited to less than
40mA.
Note 3: A heat sink may be required to keep the junction temperature
below the absolute maximum rating when the output is shorted
indefinitely.
Note 4: The LT6236C/LT6236I/LT6236H, the LT6237C/LT6237I/LT6237H
and the LT6238C/LT6238I/LT6238H are guaranteed functional over the
temperature range of –40°C to 125°C.
Note 5: The LT6236C/LT6237C/LT6238C are guaranteed to meet specified
performance from 0°C to 70°C. The LT6236I/LT6237I/LT6238I are
guaranteed to meet specified performance from –40°C to 85°C.
The LT6236H/LT6237H/LT6238H are guaranteed to meet specified
performance from –40°C to 125°C. The LT6236C/LT6237C/LT6238C are
designed, characterized and expected to meet specified performance from
–40°C to 85°C, but are not tested or QA sampled at these temperatures.
Note 6: Matching parameters are the difference between the two amplifiers
A and D and between B and C of the LT6238 and between the two
amplifiers of the LT6237.
Note 7: Minimum supply voltage is guaranteed by power supply rejection
ratio test.
Note 8: Output voltage swings are measured between the output and
power supply rails.
Note 9: Full-power bandwidth is calculated from the slew rate:
FPBW = SR/2πVP
Note 10: This parameter is not 100% tested.
LT6236/LT6237/LT6238
11
623637fb
For more information www.linear.com/LT6236
Typical perForMance characTerisTics
Input Bias Current
vs Common Mode Voltage Input Bias Current vs Temperature
Output Saturation Voltage
vs Load Current (Output Low)
VOS Distribution
Supply Current vs Supply Voltage
(Per Amplifier)
Offset Voltage vs Input Common
Mode Voltage
Output Saturation Voltage
vs Load Current (Output High) Minimum Supply Voltage
Output Short-Circuit Current
vs Power Supply Voltage
INPUT OFFSET VOLTAGE (µV)
–225
0
NUMBER OF UNITS
20
40
60
80
–125 –25 25 125 225
62367 GO1
100
200
180
160
140
120
–175 –75 75 175
VS = ±2.5V
VCM = 0V
MS8
TOTAL SUPPLY VOLTAGE (V)
0
SUPPLY CURRENT (mA)
6
62367 GO2
2 4 8
6
5
4
3
2
1
010 12 14
TA = 125°C
TA = 25°C
TA = –55°C
INPUT COMMON MODE VOLTAGE (V)
0
OFFSET VOLTAGE (mV)
1.5
62367 GO3
0.5 1 2
2.0
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0 3 4 52.5 3.5 4.5
TA = –55°C
VS = 5V, 0V
TA = 25°C
TA = 125°C
COMMON MODE VOLTAGE (V)
–1
INPUT BIAS CURRENT (µA)
2
62367 GO4
0 1 3
14
12
10
8
6
4
2
–2
0
456
TA = 125°C
TA = –55°C
TA = 25°C
VS = 5V, 0V
TEMPERATURE (°C)
–50
INPUT BIAS CURRENT (µA)
25
62367 GO5
–25 0 50
10
9
8
7
6
5
4
375 100 125
VCM = 4V
VCM = 1.5V
VS = 5V, 0V
LOAD CURRENT (mA)
0.01 0.1
0.001
OUTPUT SATURATION VOLTAGE (V)
0.01
10
1 10010
62367 GO6
0.1
1
VS = 5V, 0V
TA = –55°C
TA = 125°C
TA = 25°C
LOAD CURRENT (mA)
OUTPUT SATURATION VOLTAGE (V)
62367 G07
0.01 0.1
0.01
10
1 10010
0.001
0.1
1
VS = 5V, 0V
TA = –55°C
TA = 125°C
TA = 25°C
TOTAL SUPPLY VOLTAGE (V)
0
OFFSET VOLTAGE (mV)
1.5
62367 G08
0.5 1 2
1.0
0.8
0.6
0.4
0.2
0
–0.2
–0.4
–0.6
–0.8
–1.0 3 4 52.5 3.5 4.5
TA = –55°C
TA = 125°C
TA = 25°C
VCM = VS/2
POWER SUPPLY VOLTAGE (±V)
1.5
OUTPUT SHORT-CIRCUIT CURRENT (mA)
3
62367 GO9
2 2.5 3.5
70
60
40
20
50
30
10
0
–20
–40
–70
–60
–10
–30
–50
4 4.5 5
TA = 125°C
TA = –55°C
TA = –55°C
TA = 25°C
SINKING
SOURCING
TA = 25°C
TA = 125°C
LT6236/LT6237/LT6238
12
623637fb
For more information www.linear.com/LT6236
Typical perForMance characTerisTics
Open-Loop Gain Open-Loop Gain Open-Loop Gain
Offset Voltage vs Output Current Warm-Up Drift vs Time
Total Noise vs Total Source
Resistance
Balanced Current Noise
vs Frequency
Unbalanced Current Noise
vs Frequency Noise Voltage vs Frequency
OUTPUT VOLTAGE (V)
0
INPUT VOLTAGE (mV)
1.5
62367 G10
0.5 1 2
2.5
2.0
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0
–2.5 32.5
RL = 100Ω
RL = 1k
VS = 3V, 0V
TA = 25°C
OUTPUT VOLTAGE (V)
0
INPUT VOLTAGE (mV)
1.5
62367 G11
0.5 1 2
0
3 4 52.5 3.5 4.5
RL = 100Ω
RL = 1k
VS = 5V, 0V
TA = 25°C
2.5
2.0
1.5
1.0
0.5
–0.5
–1.0
–1.5
–2.0
–2.5
OUTPUT VOLTAGE (V)
–5
INPUT VOLTAGE (mV)
–2
62367 G12
–4 –3 –1
0
135024
RL = 100Ω
RL = 1k
VS = ±5V
TA = 25°C
2.5
2.0
1.5
1.0
0.5
–0.5
–1.0
–1.5
–2.0
–2.5
OUTPUT CURRENT (mA)
–75
OFFSET VOLTAGE (mV)
62367 G13
–45 –15
2.0
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0 0 30 7560–60 –30 15 45
TA = –55°C
TA = 125°C
VS = ±5V
TA = 25°C
TIME AFTER POWER-UP (s)
0
CHANGE IN OFFSET VOLTAGE (µV)
60
62367 G14
20 100
30
28
24
20
16
26
22
18
14
12
10 140
40 80 120 160
TA = 25°C
VS = ±5V
VS = ±2.5V
VS = ±1.5V
SOURCE RESISTANCE (Ω)
1
TOTAL NOISE (nV/√Hz)
10
10 1k 10k 100k
62367 G15
0.1 100
100 VS = ±2.5V
VCM = 0V
f = 100kHz
UNBALANCED
SOURCE
RESISTORS
TOTAL NOISE
RESISTOR NOISE
AMPLIFIER NOISE VOLTAGE
FREQUENCY (Hz)
10
0
BALANCED CURRENT NOISE (pA/√Hz)
6
7
8VS = ±2.5V
VCM = 0V
100 1k 10k 100k 1M 10M
62367 G56
5
4
3
2
1
125°C
85°C
25°C
–40°C
FREQUENCY (Hz)
10
0
UNBALANCED CURRENT NOISE (pA/√Hz)
6
7
8VS = ±2.5V
VCM = 0V
100 1k 10k 100k 1M 10M
62367 G57
5
4
3
2
1
125°C
85°C
25°C
–40°C
FREQUENCY (Hz)
10
0
INPUT VOLTAGE NOISE DENSITY (nV/√Hz)
6
7
8VS = ±2.5V
VCM = 0V
100 1k 10k 100k 1M 10M 100M
62367 G58
5
4
3
2
1
125°C
85°C
25°C
–40°C
LT6236/LT6237/LT6238
13
623637fb
For more information www.linear.com/LT6236
Typical perForMance characTerisTics
Open-Loop Gain vs Frequency
Gain Bandwidth and Phase
Margin vs Supply Voltage Slew Rate vs Temperature Output Impedance vs Frequency
Common Mode Rejection Ratio
vs Frequency Channel Separation vs Frequency
Power Supply Rejection Ratio
vs Frequency
FREQUENCY (Hz)
GAIN (dB)
80
70
50
30
0
–10
60
40
10
20
–20
PHASE (dB)
120
100
60
20
–60
80
40
–20
–40
0
–80
100k 10M 100M 1G
62367 G19
1M
CL = 5pF
RL = 1k
VCM = VS/2
PHASE
GAIN
VS = ±5V
VS = 3V, 0V
VS = ±5V
VS = 3V, 0V
TOTAL SUPPLY VOLTAGE (V)
0
GAIN BANDWIDTH (MHz)
6
62367 G20
2 4 8
220
240
200
180
140
160
PHASE MARGIN (DEG)
70
60
50
40
10 12 14
PHASE MARGIN
GAIN BANDWIDTH
TA = 25°C
CL = 5pF
RL = 1k
TEMPERATURE (°C)
–55
SLEW RATE (V/µs)
5
62367 G21
–35 –15 45
90
100
110
120
80
70
50
20
30
60
40
8525 65 105 125
VS = ±5V FALLING
VS = ±2.5V RISING
AV = –1
RF = RG = 1k
VS = ±5V RISING
VS = ±2.5V FALLING
FREQUENCY (Hz)
1
OUTPUT IMPEDANCE (Ω)
10
100k 10M 100M
62367 G22
0.01
0.1
1M
1k
100
VS = 5V, 0V
AV = 10
AV = 1
AV = 2
FREQUENCY (Hz)
20
COMMON MODE REJECTION RATIO (dB)
40
60
80
120
100
10k 100M100k 1G10M
62367 G23
01M
VS = 5V, 0V
VCM = VS/2
FREQUENCY (Hz)
20
POWER SUPPLY REJECTION RATIO (dB)
40
60
80
120
100
1k 10k 100M100k 10M
62367 G25
01M
VS = 5V, 0V
TA = 25°C
VCM = VS/2
NEGATIVE SUPPLY
POSITIVE SUPPLY
Gain Bandwidth and Phase
Margin vs Temperature
TEMPERATURE (°C)
–55
GAIN BANDWIDTH (MHz)
5
62367 G18
–25 35
240
220
200
180
140
160
PHASE MARGIN (DEG)
70
60
50
40
65 95 125
VS = ±5V
VS = 3V, 0V
VS = ±5V
VS = 3V, 0V
PHASE MARGIN
GAIN BANDWIDTH
CL = 5pF
RL = 1k
VCM = VS/2
0.1Hz to 10Hz Input Voltage
Noise
5s/DIV
62367 G17
100nV
100nV/DIV
–100nV
VS = ±2.5V
FREQUENCY (Hz)
100k
–100
CHANNEL SEPARATION (dB)
–90
–80
–70
–60
1M 10M 100M
62367 G24
–110
–120
–130
–140
–50
–40 VS = ±2.5V
AV = 1
125°C
85°C
25°C
–40°C
LT6236/LT6237/LT6238
14
623637fb
For more information www.linear.com/LT6236
Typical perForMance characTerisTics
Series Output Resistance and
Overshoot vs Capacitive Load Series Output Resistance and
Overshoot vs Capacitive Load
Settling Time vs Output Step
(Noninverting)
18-Bit Settling Time to 2VP-P
Output Step
18-Bit Settling Time to 4VP-P
Output Step
Settling Time vs Output Step
(Inverting)
Maximum Undistorted Output
Signal vs Frequency
Maximum Undistorted Output
Signal vs Frequency
Maximum Undistorted Output
Signal vs Frequency
CAPACITIVE LOAD (pF)
10
OVERSHOOT (%)
50
45
40
35
30
25
20
15
10
5
0100 1000
62367 G26
VS = 5V, 0V
AV = 1
RS = 10Ω
RS = 20Ω
RS = 50Ω
RL = 50Ω
CAPACITIVE LOAD (pF)
10
OVERSHOOT (%)
50
45
40
35
30
25
20
15
10
5
0100 1000
62367 G27
VS = 5V, 0V
AV = 2
RS = 10Ω
RS = 20Ω
RS = 50Ω
RL = 50Ω
OUTPUT STEP (V)
–4
SETTLING TIME (ns)
0
62367 G28
–3 –2 –1 1
100
200
150
50
0234
1mV
10mV
1mV
10mV
VS = ±5V
TA = 25°C
AV = 1
+
–
500Ω
VOUT
VIN
OUTPUT STEP (V)
–4
SETTLING TIME (ns)
0
62367 G29
–3 –2 –1 1
200
150
0
50
100
234
1mV
10mV
1mV
10mV
VS = ±5V
TA = 25°C
AV = –1
+
–
500Ω
500Ω
VOUT
VIN
FREQUENCY (Hz)
10k
OUTPUT VOLTAGE SWING (VP-P)
10
9
8
7
6
5
4
3
2
100k 1M 10M
62367 G30
VS = ±5V
TA = 25°C
HD2, HD3 < –40dBc
AV = –1
AV = 2
0.5µs/DIV
OUTPUT VOLTAGE (V)
2.0
1.5
1.0
0.5
0.0
62367 G27a
SETTLING RESIDUE (µV)
60
45
30
15
0
–15
–30
–45
–60
VS = ±2.5V
AV = 1
SETTLING RESIDUE
1 DIV = 18-BIT ERROR
VOUT
0.5µs/DIV
OUTPUT VOLTAGE (V)
4
3
2
1
0
62367 G27b
SETTLING RESIDUE (µV)
60
45
30
15
0
–15
–30
–45
–60
SETTLING RESIDUE
1 DIV = 18-BIT ERROR
VOUT
VS = ±5V
AV = 1
FREQUENCY (Hz)
3.0
OUTPUT VOLTAGE SWING (VP-P)
4.0
5.0
2.5
3.5
4.5
1k 100k 1M 10M
6237 G59
2.0 10k
125°C
85°C
25°C
–40°C
VS = ±2.5V
AV = –1
RL = 1k
HD2, HD3 < –40°C
FREQUENCY (Hz)
3.0
OUTPUT VOLTAGE SWING (VP-P)
4.0
5.0
2.5
3.5
4.5
1k 100k 1M 10M
6237 G60
2.0 10k
125°C
85°C
25°C
–40°C
VS = ±2.5V
AV = 2
RL = 1k
HD2, HD3 < –40°C
LT6236/LT6237/LT6238
15
623637fb
For more information www.linear.com/LT6236
Typical perForMance characTerisTics
Distortion vs Frequency
Harmonic Distortion (HD2)
vs Frequency
Harmonic Distortion (HD3)
vs Frequency
Harmonic Distortion (HD3)
vs Frequency
Harmonic Distortion (HD2)
vs Frequency
Distortion vs Frequency
FREQUENCY (Hz)
1k
DISTORTION (dBc)
–40
–50
–60
–70
–80
–90
–130
–100
–110
–120
100k10k 1M 10M
62367 G33
VOUT = 4VP-P, HD2
VS = ±2.5V
AV = –1
RL = 1k
VOUT = 2VP-P, HD3
VOUT = 2VP-P, HD2
VOUT = 4VP-P, HD3
FREQUENCY (Hz)
1k
DISTORTION (dBc)
–50
–60
–70
–80
–90
–100
–110
–120
–130
100k10k 1M 10M
62367 G34
VS = ±5V
AV = –1
RL = 1k
VOUT = 4VP-P, HD3
VOUT = 2VP-P, HD3
VOUT = 4VP-P, HD2
VOUT = 2VP-P, HD2
Distortion vs Frequency
FREQUENCY (Hz)
1k 10k
DISTORTION (dBc)
–50
–60
–70
–80
–90
–100
–110
–120
–130
100k 1M 10M
62367 G32
VS = ±5V
AV = 1
RL = 1k
VOUT = 4VP-P, HD2
VOUT = 2VP-P, HD2
VOUT = 2VP-P, HD3
VOUT = 4VP-P, HD3
FREQUENCY (Hz)
1k 10k
–100
DISTORTION (dBc)
–90
–80
–70
–60
100k 1M 10M
62367 G61
–110
–120
–130
–50
–40
125°C
85°C
25°C
–40°C
VS = ±2.5V
AV = 1
VOUT = 2VP-P
RL = 1k
FREQUENCY (Hz)
1k 10k
–100
DISTORTION (dBc)
–90
–80
–70
–60
100k 1M 10M
62367 G62
–110
–120
–130
–50
–40
125°C
85°C
25°C
–40°C
VS = ±2.5V
AV = 1
VOUT = 2VP-P
RL = 1k
FREQUENCY (Hz)
1k 10k
–100
DISTORTION (dBc)
–90
–80
–70
–60
100k 1M 10M
62367 G63
–110
–120
–130
–50
–40
125°C
85°C
25°C
–40°C
VS = ±2.5V
AV = 2
VOUT = 2VP-P
RL = 1k
FREQUENCY (Hz)
1k 10k
–100
DISTORTION (dBc)
–90
–80
–70
–60
100k 1M 10M
62367 G64
–110
–120
–130
–50
–40
125°C
85°C
25°C
–40°C
VS = ±2.5V
AV = 2
VOUT = 2VP-P
RL = 1k
LT6236/LT6237/LT6238
16
623637fb
For more information www.linear.com/LT6236
Typical perForMance characTerisTics
Large-Signal Response Output Overdrive Recovery
(LT6236) ENABLE Characteristics
Supply Current
vs ENABLE Pin Voltage
ENABLE Pin Current
vs ENABLE Pin Voltage ENABLE Pin Response Time
0V
5V
–5V
2V/DIV
200ns/DIV 62367 G37
VS = ±5V
AV = 1
RL = 1k
0V
0V
VIN
1V/DIV
VOUT
2V/DIV
200ns/DIV 62367 G38
VS = ±2.5V
AV = 3
PIN VOLTAGE (V)
SUPPLY CURRENT (mA)
–1.0
62367 G39
–2.0 0
4.5
4.0
3.5
3.0
2.5
2.0
1.0
0.5
1.5
01.0 2.0
VS = ±2.5V
TA = 125°C
TA = 25°C
TA = –55°C
PIN VOLTAGE (V)
ENABLE PIN CURRENT (µA)
62367 G40
30
25
20
15
10
5
0
TA = 125°C
VS = ±2.5V
AV = 1
TA = 25°C
TA = –55°C
–1.0
–2.0 0 1.0 2.0
0.5V
0V
0V
5V
ENABLE PIN
VOUT
100µs/DIV 62367 G41
VS = ±2.5V
VIN = 0.5V
AV = 1
RL = 1k
Large-Signal Response Small-Signal Response
2V
0V
–2V
200ns/DIV 62367 G35
VS = ±2.5V
AV = –1
RL = 1k
1V/DIV
0V
50mV/DIV
200ns/DIV 62367 G36
VS = ±2.5V
AV = 1
RL = 1k
LT6236/LT6237/LT6238
17
623637fb
For more information www.linear.com/LT6236
Functional Description
Figure 1 is a simplified schematic of the LT6236/LT6237/
LT6238, which has a pair of low noise input transistors
Q1 and Q2. A simple current mirror Q3/Q4 converts the
differential signal to a single-ended output, and these
transistors are degenerated to reduce their contribution
to the overall noise. Capacitor C1 reduces the unity cross
frequency and improves the frequency stability without
degrading the gain bandwidth of the amplifier. Capacitor
CM sets the overall amplifier gain bandwidth. The differ-
ential drive generator supplies current to transistors Q5
and Q6 that provide rail-to-rail output swing.
Input Protection
Back-to-back diodes, D1 and D2, limit the differential
input voltage to ±0.7V. The inputs of the LT6236/LT6237/
LT6238 do not have internal resistors in series with the
input transistors. This technique is often used to protect
the input devices from over voltage that causes excessive
current to flow. The addition of these resistors would
significantly degrade the voltage noise of these amplifiers.
For instance, a 100Ω resistor in series with each input
would generate 1.8nV/√Hz of noise, and the total amplifier
noise voltage would rise from 1.1nV/√Hz to 2.1nV/√Hz.
Once the input differential voltage exceeds ±0.7V, steady
state current conducted through the protection diodes
should be limited to ±40mA. This implies 25Ω of protec-
tion resistance is necessary per volt of overdrive beyond
applicaTions inForMaTion
±0.7V. These input diodes are rugged enough to handle
transient currents due to amplifier slew rate overdrive and
clipping without protection resistors. Figure 2 shows the
output response to an input overdrive with the amplifier
connected as a voltage follower. With the input signal
low, current source I1 saturates and the differential drive
generator drives Q6 into saturation so the output voltage
swings all the way to V–. The input can swing positive
until transistor Q2 saturates into current mirror Q3/Q4.
When saturation occurs, the output tries to phase invert,
but diode D2 conducts current from the signal source to
the output through the feedback connection. The output
is clamped a diode drop below the input. In Figure 2, the
input signal generator is limiting at about 20mA.
With the amplifier connected in a gain of AV ≥ 2, the output
can invert with very heavy overdrive. To avoid this inver-
sion, limit the input overdrive to 0.5V beyond the power
supply rails.
Figure 1. Simplified Schematic
ENABLE
DESD6
DESD5
–V
+V
+VIN
–VIN +V
62367 F01
BIAS
DIFFERENTIAL
DRIVE GENERATOR
VOUT
+V
CM
I1
–V
DESD3
–V
–V
DESD4
+V
DESD1
–V
DESD2
+V
D1
C1
D2
Q5
Q6
Q4
Q2
Q3
Q1
Figure 2. VS = ±2.5V, AV = 1 with Large Overdrive
2.5V
0V
–2.5V
500µs/DIV 62367 F02
1V/DIV
LT6236/LT6237/LT6238
18
623637fb
For more information www.linear.com/LT6236
applicaTions inForMaTion
ESD
The LT6236/LT6237/LT6238 have reverse-biased ESD
protection diodes on all inputs and outputs as shown in
Figure 1. If these pins are forced beyond either supply,
unlimited current will flow through these diodes. If the cur-
rent is transient and limited to 100mA or less, no damage
to the device will occur.
Noise
The noise voltage of the LT6236/LT6237/LT6238 is equiva-
lent to that of a 75Ω resistor, and for the lowest possible
noise it is desirable to keep the source and feedback resis-
tance at or below this value, i.e. RS + RG||RFB ≤ 75Ω. With
RS + RG||RFB = 75Ω the total noise of the amplifier is:
eN=(1.1nV)2+(1.1nV)2=1.55nV/ Hz
Below this resistance value, the amplifier dominates the
noise, but in the region between 75Ω and about 3k, the
noise is dominated by the resistor thermal noise. As the
total resistance is further increased beyond 3k, the amplifier
noise current multiplied by the total resistance eventually
dominates the noise.
The product of eN • √ISUPPLY is an interesting way to gauge
low noise amplifiers. Most low noise amplifiers have high
ISUPPLY. In applications that require low noise voltage with
the lowest possible supply current, this product can be
helpful.
The LT6236/LT6237/LT6238 have an eN • √ISUPPLY of only
1.9 per amplifier, yet it is common to see amplifiers with
similar noise specifications to have eN • √ISUPPLY as high
as 13.5. For a complete discussion of amplifier noise, see
the LT1028 data sheet.
ENABLE Pin
The LT6236 includes an ENABLE pin that shuts down the
amplifier to 10μA maximum supply current. For normal
operation, the ENABLE pin must be pulled to at least
2.7V below V+. The ENABLE pin must be driven high to
within 0.35V of V+ to shut down the amplifier. This can
be accomplished with simple gate logic; however care
must be taken if the logic and the LT6236 operate from
different supplies. If this is the case, open drain logic can
be used with a pull-up resistor to ensure that the ampli-
fier remains off. When the ENABLE pin is left floating, the
amplifier is inactive. However, care should be taken to
control the leakage current through the pin so the amplifier
is not inadvertently turned on. See Typical Performance
Characteristics.
The output leakage current when disabled is very low;
however, current can flow into the input protection diodes,
D1 and D2, if the output voltage exceeds the input voltage
by a diode drop.
Power Dissipation
The LT6237MS8 combines high speed with large output
current in a small package. Due to the wide supply volt-
age range, it is possible to exceed the maximum junction
temperature under certain conditions. Maximum junction
temperature (TJ) is calculated from the ambient tempera-
ture (TA) and power dissipation (PD) as follows:
TJ = TA + (PD • θJA)
The power dissipation in the IC is the function of the sup-
ply voltage, output voltage and the load resistance. For
a given supply voltage, the worst-case power dissipation
PD(MAX) occurs at the maximum quiescent supply current
and at the output voltage which is half of either supply
voltage (or the maximum swing if it is less than half the
supply voltage). PD(MAX) is given by:
PD(MAX) = (V+– V–)( IS(MAX)) + (V+/2)2/RL
Example: An LT6237HMS8 in the 8-Lead MSOP package
has a thermal resistance of θJA = 273°C/W. Operating
on ±5V supplies with one amplifier driving a 1k load, the
worst-case power dissipation is given by:
PD(MAX) = (10V)(11mA) + (2.5V)2/1000Ω= 116mW
In this example, the maximum ambient temperature that
the part is allowed to operate is:
TA = TJ - (PD(MAX) × 273°C/W)
TA = 150°C – (116mW)(273°C/W) = 118.3°C
To operate the device at a higher ambient temperature for
the same conditions, switch to using two LT6236 in the
6-Lead TSOT-23, or a single LT6237 in the 8-Lead DFN
package.
LT6236/LT6237/LT6238
19
623637fb
For more information www.linear.com/LT6236
Interfacing to ADCs
When driving an ADC, a single-pole, passive RC filter should
be used between the outputs of the LT6236/LT6237/LT6238
and the inputs of the ADC. The sampling process of ADCs
creates a charge transient from the switching of the ADC
sampling capacitor. This momentarily “shorts” the output
of the amplifier as charge is transferred between amplifier
and sampling capacitor. The amplifier must recover and
settle from this load transient before the acquisition period
has ended for a valid representation of the input signal.
The RC network between the outputs of the driver and
the inputs of the ADC decouples the sampling transient
of the ADC. The capacitance serves to provide the bulk
of the charge during the sampling process, while the two
resistors at the outputs of the LT6236/LT6237/LT6238 are
used to dampen and attenuate any charge injected by the
ADC. The RC filter provides the benefit of band limiting
broadband output noise.
Thanks to the very low wideband noise of the LT6236/
LT6237/LT6238, a wideband filter can be used between
the amplifier and the ADC without impacting SNR. This
is especially important with ADCs or applications that
require full settling in between each conversion.
The selection of an appropriate filter depends on the specific
ADC, however the following procedure is suggested for
choosing filter component values. Begin by selecting an
appropriate RC time constant for the input signal. Gener-
ally, longer time constants improve SNR at the expense of
applicaTions inForMaTion
settling time. Output transient settling to 18-bit accuracy
will require over twelve RC time constants. To select the
resistor value, the resistors in the decoupling network
should be at least 10Ω. Keep in mind that these resis-
tors also serve to decouple the LT6236/LT6237/LT6238
outputs from load capacitance. Too large of a resistor will
leave insufficient settling time. Too small of a resistor will
not properly dampen the load transient of the sampling
process, and prolong the time required for settling. For
lowest distortion, choose capacitors with low dielectric
absorption such as a C0G multilayer ceramic capacitor. In
general, large capacitor values attenuate the fixed nonlinear
charge kickback, however very large capacitor values will
detrimentally load the driver at the desired input frequency
and cause driver distortion. Smaller input swings allow
for larger filter capacitor values due to decreased loading
demands on the driver. This property may be limited by
the particular input amplitude dependence of differential
nonlinear kickback for the specific ADC used.
Series resistors should typically be placed at the inputs to
the ADC in order to further improve distortion performance.
These series resistors function with the ADC sampling
capacitor to filter potential ground bounce or other high
speed sampling disturbances. Additionally the resistors
limit the rise time of residual filter glitches that manage to
propagate to the driver outputs. Restricting possible glitch
propagation rise time to within the small signal bandwidth
of the driver enables less disturbed output settling.
LT6236/LT6237/LT6238
20
623637fb
For more information www.linear.com/LT6236
Typical applicaTions
Single Supply, Low Noise, Low Power, Bandpass Filter with Gain = 10
Driving a Fully Differential ADC
Driving a Single-Ended ADC
+
–
R2
732Ω
R4
10k
C3
0.1µF
EN
LT6236
f0 = 1 = 1MHz
C = √C1C2, R = R1 = R2
f0 =
(
732Ω
)
MHz, MAXIMUM f0 = 1MHz
f–3dB =
f0
AV = 20dB at f0
EN = 4µVRMS INPUT REFERRED
IS = 3.7mA FOR V+ = 5V
62367 TA02
0.1µF
C2
47pF
C1
1000pF R3
10k
R1
732Ω
VOUT
V+
VIN
2πRC
R
2.5
FREQUENCY (Hz)
100k
GAIN (dB)
23
3
–7 1M 10M
62367 TA03
Frequency Response Plot of Bandpass Filter
62367 TA04
IN–
IN+
270pF
38.3Ω
38.3Ω
6V
–2V
1/2 LT6237
LOWPASS FILTERS
1/2 LT6237
LTC2389-18
270pF
+
–
+
–
49.9Ω
49.9Ω
VA
VB
4.096V
0V
4.096V
0V
4.096V
0V
OR OR
62367 TA05
IN–
IN+
1nF
10Ω
LOWPASS FILTER
LTC2389-18
LT6236
+
–
4.096V
0V
6V
–2V 49.9Ω
49.9Ω
LT6236/LT6237/LT6238
21
623637fb
For more information www.linear.com/LT6236
package DescripTion
1.50 – 1.75
(NOTE 4)
2.80 BSC
0.30 – 0.45
6 PLCS (NOTE 3)
DATUM ‘A’
0.09 – 0.20
(NOTE 3) S6 TSOT-23 0302
2.90 BSC
(NOTE 4)
0.95 BSC
1.90 BSC
0.80 – 0.90
1.00 MAX 0.01 – 0.10
0.20 BSC
0.30 – 0.50 REF
PIN ONE ID
NOTE:
1. DIMENSIONS ARE IN MILLIMETERS
2. DRAWING NOT TO SCALE
3. DIMENSIONS ARE INCLUSIVE OF PLATING
4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
5. MOLD FLASH SHALL NOT EXCEED 0.254mm
6. JEDEC PACKAGE REFERENCE IS MO-193
3.85 MAX
0.62
MAX
0.95
REF
RECOMMENDED SOLDER PAD LAYOUT
PER IPC CALCULATOR
1.4 MIN
2.62 REF
1.22 REF
S6 Package
6-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1636)
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
LT6236/LT6237/LT6238
22
623637fb
For more information www.linear.com/LT6236
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
package DescripTion
3.00 ±0.10
(4 SIDES)
NOTE:
1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-1)
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION
ON TOP AND BOTTOM OF PACKAGE
0.40 ±0.10
BOTTOM VIEW—EXPOSED PAD
1.65 ±0.10
(2 SIDES)
0.75 ±0.05
R = 0.125
TYP
2.38 ±0.10
14
85
PIN 1
TOP MARK
(NOTE 6)
0.200 REF
0.00 – 0.05
(DD8) DFN 0509 REV C
0.25 ±0.05
2.38 ±0.05
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED
1.65 ±0.05
(2 SIDES)2.10 ±0.05
0.50
BSC
0.70 ±0.05
3.5 ±0.05
PACKAGE
OUTLINE
0.25 ±0.05
0.50 BSC
DD Package
8-Lead Plastic DFN (3mm × 3mm)
(Reference LTC DWG # 05-08-1698 Rev C)
LT6236/LT6237/LT6238
23
623637fb
For more information www.linear.com/LT6236
package DescripTion
MSOP (MS8) 0213 REV G
0.53 ±0.152
(.021 ±.006)
SEATING
PLANE
NOTE:
1. DIMENSIONS IN MILLIMETER/(INCH)
2. DRAWING NOT TO SCALE
3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS.
MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX
0.18
(.007)
0.254
(.010)
1.10
(.043)
MAX
0.22 – 0.38
(.009 – .015)
TYP
0.1016 ±0.0508
(.004 ±.002)
0.86
(.034)
REF
0.65
(.0256)
BSC
0° – 6° TYP
DETAIL “A”
DETAIL “A”
GAUGE PLANE
1 2 34
4.90 ±0.152
(.193 ±.006)
8765
3.00 ±0.102
(.118 ±.004)
(NOTE 3)
3.00 ±0.102
(.118 ±.004)
(NOTE 4)
0.52
(.0205)
REF
5.10
(.201)
MIN
3.20 – 3.45
(.126 – .136)
0.889 ±0.127
(.035 ±.005)
RECOMMENDED SOLDER PAD LAYOUT
0.42 ± 0.038
(.0165 ±.0015)
TYP
0.65
(.0256)
BSC
MS8 Package
8-Lead Plastic MSOP
(Reference LTC DWG # 05-08-1660 Rev G)
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
LT6236/LT6237/LT6238
24
623637fb
For more information www.linear.com/LT6236
package DescripTion
GN16 REV B 0212
1 2 345678
.229 – .244
(5.817 – 6.198)
.150 – .157**
(3.810 – 3.988)
16 15 14 13
.189 – .196*
(4.801 – 4.978)
12 11 10 9
.016 – .050
(0.406 – 1.270)
.015 ±.004
(0.38 ±0.10) × 45°
0° – 8° TYP
.007 – .0098
(0.178 – 0.249)
.0532 – .0688
(1.35 – 1.75)
.008 – .012
(0.203 – 0.305)
TYP
.004 – .0098
(0.102 – 0.249)
.0250
(0.635)
BSC
.009
(0.229)
REF
.254 MIN
RECOMMENDED SOLDER PAD LAYOUT
.150 – .165
.0250 BSC.0165 ±.0015
.045 ±.005
* DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
INCHES
(MILLIMETERS)
NOTE:
1. CONTROLLING DIMENSION: INCHES
2. DIMENSIONS ARE IN
3. DRAWING NOT TO SCALE
4. PIN 1 CAN BE BEVEL EDGE OR A DIMPLE
GN Package
16-Lead Plastic SSOP (Narrow .150 Inch)
(Reference LTC DWG # 05-08-1641 Rev B)
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
LT6236/LT6237/LT6238
25
623637fb
For more information www.linear.com/LT6236
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
revision hisTory
REV DATE DESCRIPTION PAGE NUMBER
A 09/13 Added LT6238 quad All
B 09/14 Corrected ISINK condition for VOL specification.
Corrected VO condition for AVOL specification.
Added LT6238 to ESD discussion.
5, 6, 9, 10
9, 10
18
LT6236/LT6237/LT6238
26
623637fb
For more information www.linear.com/LT6236
LINEAR TECHNOLOGY CORPORATION 2012
LT 0914 REV B • PRINTED IN USA
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com/LT6236
relaTeD parTs
Typical applicaTion
PART NUMBER DESCRIPTION COMMENTS
OPERATIONAL AMPLIFIERS
LT6230/LT6231/LT6232 Single, Dual, Quad Low Noise, Rail-to-Rail Output. 1.1nV/√Hz
LT6350 Low Noise, Single-Ended to Differential Converter/ADC Driver 4.8mA, –97dBc Distortion at 100kHz, 4VP-P Output
LTC6246/LTC6247/LTC6248 Single/Dual/Quad 180MHz Rail-to-Rail Low Power Op Amps 1mA/Amplifier, 4.2nV/√Hz
LTC6360 1GHz Very Low Noise Single-Ended SAR ADC Driver with
True Zero Output HD2 = –103dBc and HD3 = –109dBc for 4VP-P Output at 40kHz
ADCs
LTC2389-18 Low Power 18-Bit SAR ADC 2.5Msps
LTC2389-16 Low Power 16-Bit SAR ADC 2.5Msps
LTC2379-18
LTC2378-18
LTC2377-18
LTC2376-18
Low Power 18-Bit SAR ADC 1.6Msps
1Msps
500ksps
250ksps
+
–
R1
1.5k
R2
1.5k
C2
0.1µF
5V
–5V
ENABLE
LT6236
≈200V BIAS
ADVANCED PHOTONIX
012-70-62-541
WWW.ADVANCEDPHOTONIX.COM
62367 TA06
C1
4.7pF
OUTPUT OFFSET = 500µV TYPICAL
BANDWIDTH = 20MHz
OUTPUT NOISE = 1.1mVP-P (100MHz MEASUREMENT BW)
50ns/DIV 62367 TA07
30mV/DIV
Low Power Avalanche Photodiode Transimpedance Amplifier
IS = 3.3mA
Photodiode Amplifier Time Domain Response
The LT6236 is configured as a transimpedance amplifier
with an I-to-V conversion gain of 1.5kΩ set by R1. The
LT6236 is ideally suited to this application because of its
low input offset voltage and current, and its low noise.
This is because the 1.5k resistor has an inherent thermal
noise of 5nV/√Hz or 3.4pA/√Hz at room temperature, while
the LT6236 contributes only 1.1nV/√Hz and 2.4pA/√Hz.
So, with respect to both voltage and current noises, the
LT6236 is actually quieter than the gain resistor. The
circuit uses an avalanche photodiode with the cathode
biased to approximately 200V. When light is incident on
the photodiode, it induces a current
IPD which flows into the amplifier circuit. The amplifier
output falls negative to maintain balance at its inputs.
The transfer function is therefore VOUT = –IPD • 1.5k. C1
ensures stability and good settling characteristics. Output
offset was measured at 280µV, so low in part because R2
serves to cancel the DC effects of bias current. Output
noise was measured at 1.1mVP–P on a 100MHz measure-
ment bandwidth, with C2 shunting R2’s thermal noise. As
shown in the scope photo, the rise time is 17ns, indicating
a signal bandwidth of 20MHz.
