FeaTures
n
n
n
n
n
n
n
n
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LT6236/LT6237/LT6238
Rail-to-Rail Output
215MHz, 1.1nV/√Hz
Op Amp/SAR ADC Driver
DescripTion
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.
L,
LT, LTC, LTM, 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.
n
Low Noise: 1.1nV/√Hz
Low Supply Current: 3.5mA/Amp Max
Low Offset Voltage: 350µV Max
Fast Settling Time: 570ns to 18-Bit, 2V
P-P
Output
Low Distortion: THD = –116.8dB at 2kHz
Wide Supply Range: 3V to 12.6V
Output Swings Rail-to-Rail
215MHz Gain-Bandwidth Product
Specified Temperature Range: –40°C to 125°C
LT6236 Shutdown to 10µA Max
LT6236 in Low Profile (1mm) ThinSOT™ Package
Dual LT6237 in 3mm
×
3mm 8-Lead DFN and 8-Lead
MSOP Packages
LT6238 in 16-Lead SSOP Package
applicaTions
n
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16-Bit and 18-Bit SAR ADC Drivers
Active Filters
Low Noise, Low Power Signal Processing
Typical applicaTion
Differentially Driving a SAR ADC
IN
+
+
–
V
S+
= 6V
LOWPASS FILTERS
38.3
270pF
49.9
IN
+
LTC2389-18
38.3
270pF
49.9
IN
–
623637 TA01a
LT6237 Driving LTC2389-18 f
IN
= 2kHz,
–1dBFS, 32768-Point FFT
0
V
OUT
= 7.3V
P-P
–10
HD2 = –129.5dBc
–20
HD3 = –118.7dBc
–30
SFDR = 117.7dB
–40
THD = –116.8dB
–50
SNR = 99.7dB
–60
SINAD = 98.9dB
–70
–80
–90
–100
–110
–120
–130
–140
–150
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2
FREQUENCY (MHz)
62367 TA01b
1/2 LT6237
18-BIT
2.5Msps
–
1/2 LT6237
IN
–
+
V
S–
= –2V
AMPLITUDE (dBFS)
623637fb
For more information
www.linear.com/LT6236
1
LT6236/LT6237/LT6238
absoluTe MaxiMuM raTings
(Note 1)
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
Specified Temperature Range (Note 5).....–40°C to125°C
Maximum Junction Temperature .......................... 150°C
Storage Temperature Range .................. –65°C to 150°C
pin conFiguraTion
TOP VIEW
TOP VIEW
TOP VIEW
OUT 1
V
–
2
+IN 3
6 V
+
5
ENABLE
4 –IN
OUT A
–IN A
+IN A
V
–
1
2
3
4
9
8 V
+
7 OUT B
6 –IN B
5 +IN B
OUT A
–IN A
+IN A
V
–
1
2
3
4
TOP VIEW
8
7
6
5
V
+
OUT B
–IN B
+IN B
OUT A
–IN A
+IN A
V
+
+IN B
–IN B
OUT B
NC
1
3
4
5
6
7
8
+
B
–
16 OUT D
A
D
15 –IN D
14 +IN D
13 V
–
C
–
+
+
–
+
–
2
12 +IN C
11 –IN C
10 OUT C
9
NC
S6 PACKAGE
6-LEAD PLASTIC TSOT-23
T
JMAX
= 150°C,
θ
JA
= 192°C/W
DD PACKAGE
8-LEAD (3mm
×
3mm) PLASTIC DFN
T
JMAX
= 150°C,
θ
JA
= 43°C/W
UNDERSIDE METAL CONNECTED TO V
–
(PCB CONNECTION OPTIONAL)
MS8 PACKAGE
8-LEAD PLASTIC MSOP
T
JMAX
= 150°C,
θ
JA
= 273°C/W
GN PACKAGE
16-LEAD NARROW PLASTIC SSOP
T
JMAX
= 150°C,
θ
JA
= 110°C/W
orDer inForMaTion
LEAD FREE FINISH
LT6236CS6#TRMPBF
LT6236IS6#TRMPBF
LT6236HS6#TRMPBF
LT6237CDD#PBF
LT6237IDD#PBF
LT6237HDD#PBF
LT6237CMS8#PBF
LT6237IMS8#PBF
LT6237HMS8#PBF
LT6238CGN#PBF
LT6238IGN#PBF
LT6238HGN#PBF
TAPE AND REEL
LT6236CS6#TRPBF
LT6236IS6#TRPBF
LT6236HS6#TRPBF
LT6237CDD#TRPBF
LT6237IDD#TRPBF
LT6237HDD#TRPBF
LT6237CMS8#TRPBF
LT6237IMS8#TRPBF
LT6237HMS8#TRPBF
LT6238CGN#TRPBF
LT6238IGN#TRPBF
LT6238HGN#TRPBF
PART MARKING*
LTGHM
LTGHM
LTGHM
LGHN
LGHN
LGHN
LTGHP
LTGHP
LTGHP
6238
6238
6238
PACKAGE DESCRIPTION
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
8-Lead (3mm
×
3mm) Plastic DFN
8-Lead (3mm
×
3mm) Plastic DFN
8-Lead (3mm
×
3mm) Plastic DFN
8-Lead Plastic MSOP
8-Lead Plastic MSOP
8-Lead Plastic MSOP
16-Lead Narrow Plastic SSOP
16-Lead Narrow Plastic SSOP
16-Lead Narrow Plastic SSOP
SPECIFIED
TEMPERATURE RANGE
0°C to 70°C
–40°C to 85°C
–40°C to 125°C
0°C to 70°C
–40°C to 85°C
–40°C to 125°C
0°C to 70°C
–40°C to 85°C
–40°C to 125°C
0°C to 70°C
–40°C to 85°C
–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/
2
623637fb
For more information
www.linear.com/LT6236
LT6236/LT6237/LT6238
elecTrical characTerisTics
ENABLE
= 0V, unless otherwise noted.
Input Offset Voltage
SYMBOL PARAMETER
V
OS
T
A
= 25°C, V
S
= 5V, 0V; V
S
= 3.3V, 0V; V
CM
= V
OUT
= half supply,
MIN
TYP
100
50
75
100
5
0.1
0.1
MAX
500
350
450
600
10
0.9
0.6
1.7
UNIT
µV
µV
µV
µV
µA
µA
µA
nV
P-P
nV/√Hz
pA/√Hz
pA/√Hz
MΩ
kΩ
pF
pF
V/mV
V/mV
V/mV
V/mV
V/mV
4
2.65
115
115
115
4
85
240
185
5
90
325
250
±30
±25
±45
±40
3.15
0.2
–25
3.5
10
–75
40
190
460
350
50
200
600
400
V
V
dB
dB
dB
V
mV
mV
mV
mV
mV
mV
mV
mV
mA
mA
mA
µA
µA
CONDITIONS
LT6236
LT6237MS8, LT6238GN
LT6237DD8
Input Offset Voltage Match
(Channel-to-Channel) (Note 6)
I
B
I
OS
e
n
i
n
R
IN
C
IN
A
VOL
Input Bias Current
I
B
Match (Channel-to-Channel) (Note 6)
Input Offset Current
Input Noise Voltage
Input Noise Voltage Density
Input Noise Current Density, Balanced Source
Input Noise Current Density, Unbalanced Source
Input Resistance
Input Capacitance
Large-Signal Gain
0.1Hz to 10Hz
f = 10kHz, V
S
= 5V
f = 10kHz, V
S
= 5V, R
S
= 10k
f = 10kHz, V
S
= 5V, R
S
= 10k
Common Mode
Differential Mode
Common Mode
Differential Mode
V
S
= 5V, V
O
= 0.5V to 4.5V, R
L
= 10k to V
S
/2
V
S
= 5V, V
O
= 0.5V to 4.5V, R
L
= 1k to V
S
/2
V
S
= 5V, V
O
= 1V to 4V, R
L
= 100Ω to V
S
/2
V
S
= 3.3V, V
O
= 0.65V to 2.65V, R
L
= 10k to V
S
/2
V
S
= 3.3V, V
O
= 0.65V to 2.65V, R
L
= 1k to V
S
/2
V
CM
CMRR
PSRR
V
OL
Input Voltage Range
Common Mode Rejection Ratio
Power Supply Rejection Ratio
Minimum Supply Voltage (Note 7)
Output Voltage Swing Low (Note 8)
No Load
I
SINK
= 5mA
V
S
= 5V, I
SINK
= 20mA
V
S
= 3.3V, I
SINK
= 15mA
No Load
I
SOURCE
= 5mA
V
S
= 5V, I
SOURCE
= 20mA
V
S
= 3.3V, I
SOURCE
= 15mA
V
S
= 5V
V
S
= 3.3V
ENABLE
= V
+
– 0.35V
ENABLE
= 0.3V
Guaranteed by CMRR, V
S
= 5V, 0V
Guaranteed by CMRR, V
S
= 3.3V, 0V
V
S
= 5V, V
CM
= 1.5V to 4V
V
S
= 3.3V, V
CM
= 1.15V to 2.65V
V
S
= 3V to 10V
105
21
5.4
90
16.5
1.5
1.15
90
90
90
3
180
1.1
1
2.4
6.5
7.5
2.9
7.7
200
40
9
175
32
V
OH
Output Voltage Swing High (Note 8)
I
SC
I
S
I
ENABLE
Short-Circuit Current
Supply Current per Amplifier
Disabled Supply Current per Amplifier
ENABLE
Pin Current
623637fb
For more information
www.linear.com/LT6236
3
LT6236/LT6237/LT6238
elecTrical characTerisTics
ENABLE
= 0V, unless otherwise noted.
SYMBOL PARAMETER
V
L
V
H
t
ON
t
OFF
GBW
f
–3db
SR
FPBW
t
S
ENABLE
Pin Input Voltage Low
ENABLE
Pin Input Voltage High
Output Leakage Current
Turn-On Time
Turn-Off Time
Gain-Bandwidth Product
–3dB Bandwidth
Slew Rate
Full-Power Bandwidth
Settling Time
ENABLE
= V
+
– 0.35V, V
O
= 1.5V to 3.5V
ENABLE
= 5V to 0V, R
L
= 1k, V
S
= 5V
ENABLE
= 0V to 5V, R
L
= 1k, V
S
= 5V
Frequency = 1MHz, V
S
= 5V
V
S
= 5V, R
L
= 100Ω
V
S
= 5V, A
V
= –1, R
L
= 1k, V
O
= 1.5V to 3.5V
V
S
= 5V, V
OUT
= 3V
P-P
(Note 9)
0.1%, V
S
= 5V, V
STEP
= 2V, A
V
= 1
0.01%
0.0015% (16-Bit)
4ppm (18-Bit)
42
4.4
V
+
– 0.35V
0.2
800
41
200
90
60
6.3
50
60
240
570
10
T
A
= 25°C, V
S
= 5V, 0V; V
S
= 3.3V, 0V; V
CM
= V
OUT
= half supply,
MIN
TYP
MAX
0.3
UNIT
V
V
µA
ns
µs
MHz
MHz
V/µs
MHz
ns
ns
ns
ns
CONDITIONS
The
l
denotes the specifications which apply over the 0°C < T
A
< 70°C temperature range. V
S
= 5V, 0V; V
S
= 3.3V, 0V; V
CM
= V
OUT
=
half supply,
ENABLE
= 0V, unless otherwise noted.
SYMBOL
V
OS
PARAMETER
Input Offset Voltage
CONDITIONS
LT6236
LT6237MS8, LT6238GN
LT6237DD8
l
l
l
l
MIN
TYP
MAX
600
450
550
800
UNIT
µV
µV
µV
µV
µV/°C
µV/°C
µV/°C
µV/°C
µA
µA
µA
V/mV
V/mV
V/mV
V/mV
V/mV
Input Offset Voltage Match
(Channel-to-Channel) (Note 6)
V
OS
TC
Input Offset Voltage Drift (Note 10)
LT6236
LT6237MS8
LT6237DD8
LT6238GN
l
l
l
l
l
l
l
0.5
0.3
0.4
0.5
2.0
1.4
2.2
2.2
11
1
0.7
I
B
I
OS
A
VOL
Input Bias Current
I
B
Match (Channel-to-Channel) (Note 6)
Input Offset Current
Large-Signal Gain
V
S
= 5V, V
O
= 0.5V to 4.5V, R
L
= 10k to V
S
/2
V
S
= 5V, V
O
= 0.5V to 4.5V, R
L
= 1k to V
S
/2
V
S
= 5V, V
O
= 1V to 4V, R
L
= 100Ω to V
S
/2
V
S
= 3.3V, V
O
= 0.65V to 2.65V, R
L
= 10k to V
S
/2
V
S
= 3.3V, V
O
= 0.65V to 2.65V, R
L
= 1k to V
S
/2
l
l
l
l
l
l
l
l
l
l
l
78
17
4.1
66
13
1.5
1.15
90
85
85
3
50
200
500
380
4
2.65
V
CM
CMRR
PSRR
V
OL
Input Voltage Range
Guaranteed by CMRR
V
S
= 5V, 0V
Vs = 3.3V, 0V
V
S
= 5V, V
CM
= 1.5V to 4V
V
S
= 3.3V, V
CM
= 1.15V to 2.65V
V
S
= 3V to 10V
No Load
I
SINK
= 5mA
V
S
= 5V, I
SINK
= 20mA
V
S
= 3.3V, I
SINK
= 15mA
V
V
dB
dB
dB
V
mV
mV
mV
mV
Common Mode Rejection Ratio
Power Supply Rejection Ratio
Minimum Supply Voltage (Note 7)
Output Voltage Swing Low (Note 8)
l
l
l
l
4
623637fb
For more information
www.linear.com/LT6236
LT6236/LT6237/LT6238
elecTrical characTerisTics
SYMBOL
V
OH
PARAMETER
Output Voltage Swing High (Note 8)
The
l
denotes the specifications which apply over the 0°C < T
A
< 70°C
temperature range. V
S
= 5V, 0V; V
S
= 3.3V, 0V; V
CM
= V
OUT
= half supply,
ENABLE
= 0V, unless otherwise noted.
CONDITIONS
No Load
I
SOURCE
= 5mA
V
S
= 5V, I
SOURCE
= 20mA
V
S
= 3.3V, I
SOURCE
= 15mA
V
S
= 5V
V
S
= 3.3V
ENABLE
= V
+
– 0.25V
ENABLE
= 0.3V
l
l
l
l
l
l
l
l
l
l
l
MIN
TYP
MAX
60
215
650
430
UNIT
mV
mV
mV
mV
mA
mA
I
SC
I
S
I
ENABLE
V
L
V
H
SR
FPBW
Short-Circuit Current
Supply Current per Amplifier
Disabled Supply Current per Amplifier
ENABLE
Pin Current
ENABLE
Pin Input Voltage Low
ENABLE
Pin Input Voltage High
Slew Rate
Full-Power Bandwidth (Note 9)
±25
±20
1
4.2
–85
0.3
V
+
– 0.25V
35
3.7
mA
µA
µA
V
V
V/µs
MHz
V
S
= 5V, A
V
= –1, R
L
= 1k, V
O
= 1.5V to 3.5V
V
S
= 5V, V
OUT
= 3V
P-P
l
l
The
l
denotes the specifications which apply over the –40°C < T
A
< 85°C temperature range. V
S
= 5V, 0V; V
S
= 3.3V, 0V; V
CM
= V
OUT
=
half supply,
ENABLE
= 0V, unless otherwise noted. (Note 5)
SYMBOL
V
OS
PARAMETER
Input Offset Voltage
CONDITIONS
LT6236
LT6237MS8, LT6238GN
LT6237DD8
l
l
l
l
MIN
TYP
MAX
700
550
650
1000
UNITS
µV
µV
µV
µV
µV/°C
µV/°C
µV/°C
µV/°C
µA
µA
µA
V/mV
V/mV
V/mV
V/mV
V/mV
Input Offset Voltage Match
(Channel-to-Channel) (Note 6)
V
OS
TC
Input Offset Voltage Drift (Note 10)
LT6236
LT6237MS8
LT6237DD8
LT6238GN
l
l
l
l
l
l
l
0.5
0.3
0.4
0.5
2.0
1.4
2.2
2.2
12
1.1
0.8
I
B
I
OS
A
VOL
Input Bias Current
I
B
Match (Channel-to-Channel) (Note 6)
Input Offset Current
Large-Signal Gain
V
S
= 5V, V
O
= 0.5V to 4.5V, R
L
= 10k to V
S
/2
V
S
= 5V, V
O
= 0.5V to 4.5V, R
L
= 1k to V
S
/2
V
S
= 5V, V
O
= 1V to 4V, R
L
= 100Ω to V
S
/2
l
l
l
72
16
3.6
60
12
1.5
1.15
90
85
85
3
60
210
510
390
4
2.65
V
S
= 3.3V, V
O
= 0.65V to 2.65V, R
L
= 10k to V
S
/2
l
V
S
= 3.3V, V
O
= 0.65V to 2.65V, R
L
= 1k to V
S
/2
l
V
CM
CMRR
PSRR
V
OL
Input Voltage Range
Guaranteed by CMRR
V
S
= 5V, 0V
V
S
= 3.3V, 0V
V
S
= 5V, V
CM
= 1.5V to 4V
V
S
= 3.3V, V
CM
= 1.15V to 2.65V
V
S
= 3V to 10V
No Load
I
SINK
= 5mA
V
S
= 5V, I
SINK
= 15mA
V
S
= 3.3V, I
SINK
= 15mA
l
l
l
l
l
l
l
l
l
l
V
V
dB
dB
dB
V
mV
mV
mV
mV
Common Mode Rejection Ratio
Power Supply Rejection Ratio
Minimum Supply Voltage (Note 7)
Output Voltage Swing Low (Note 8)
623637fb
For more information
www.linear.com/LT6236
5
Electronics Design Contest
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