LT6650
Micropower, 400mV
Reference with Rail-to-Rail
Buffer Amplifier in SOT-23
FEATURES
s
s
s
DESCRIPTIO
s
s
s
s
s
s
s
Low Quiescent Current 5.6
µ
A (typical)
Wide Supply Range: 1.4V to 18V
400mV Reference
±
1% Maximum Accuracy Over
Temperature at 5V
Rail-to-Rail Buffer Amplifier
0.5% 400mV Maximum Initial Accuracy at 5V
Shunt Configurable
Sinks and Sources Current
Wide Operational Range –40°C to 125°C
Externally Adjustable Output Voltage
Low Profile 1mm 5-lead SOT-23
(ThinSOT™) Package
The LT
®
6650 is a micropower, low voltage 400mV refer-
ence. Operating with supplies from 1.4V up to 18V, the
device draws only 5.6µA typical, making it ideal for low
voltage systems as well as handheld instruments and
industrial control systems. With only two resistors the
internal buffer amplifier can scale the 400mV reference to
any desired value up to the supply voltage.
The reference is postpackage-trimmed to increase the
output accuracy. The output can sink and source 200µA
over temperature. Quiescent power dissipation is 28µW.
Stability is ensured with any output capacitor of 1µF or
higher.
The LT6650 is the lowest voltage series reference available
in the 5-lead SOT-23 package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
ThinSOT is a trademark of Linear Technology Corporation.
APPLICATIO S
s
s
s
s
s
Battery-Operated Systems
Handheld Instruments
Industrial Control Systems
Data Acquisition Systems
Negative Voltage References
TYPICAL APPLICATIO
V
IN
= 1.4V TO 18V
I
Q
≈
6µA
Battery-Powered 0.4V Reference
402
LT6650 Temperature Drift
TYPICAL LT6650 PART
V
IN
= 5V
NO LOAD
SINK 200µA
400
SOURCE –200µA
399
REFERENCE VOLTAGE (mV)
4
IN
V
R
= 400mV
REFERENCE
LT6650
401
+
–
OUT 5
V
OUT
0.4V
GND
1µF
2
FB 1
1µF
398
–50 –30 –10 10 30 50 70 90 110 130
TEMPERATURE (°C)
6650 TA01b
6650 TA01a
U
6650f
U
U
1
LT6650
ABSOLUTE
(Note 1)
AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
ORDER PART
NUMBER
TOP VIEW
FB 1
GND 2
DNC* 3
4 IN
5 OUT
Total Supply Voltage (V
IN
to GND)........................... 20V
FB Voltage (Note 2) ....................... 20V to (GND – 0.3V)
Output Voltage (OUT) .................... 20V to (GND – 0.3V)
Output Short Circuit Duration .......................... Indefinite
FB Input Current ................................................... 10mA
Operating Temperature Range ............... –40°C to 125°C
Specified Temperature Range
LT6650CS5 ............................................. 0°C to 70°C
LT6650IS5 ........................................... –40°C to 85°C
LT6650HS5 (Note 3) ......................... –40°C to 125°C
Maximum Junction Temperature .......................... 150°C
Storage Temperature Range
(Note 4) ............................................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
LT6650CS5
LT6650IS5
LT6650HS5
S5 PART
MARKING
LBDV
S5 PACKAGE
5-LEAD PLASTIC TSOT-23
T
JMAX
= 150°C,
θ
JA
= 230°C/W
*Do Not Connect
The temperature grades are identified by a label on the shipping container.
Consult LTC Marketing for parts specified with wider operating temperature ranges.
The
q
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 5V, C
IN
= 1µF, FB = OUT, no DC load, C
L
= 1µF, unless
otherwise noted.
SYMBOL
V
OUT
PARAMETER
Output Voltage (Notes 4, 5)
CONDITIONS
LT6650
LT6650CS5
LT6650IS5
LT6650HS5
V
IN
∆V
OUT
/∆V
IN
Operating Input Voltage
Line Regulation
1.4V
≤
V
IN
≤
18V
1
150
LT6650CS5, LT6650IS5
LT6650HS5
∆V
OUT
/∆I
OUT
Load Regulation (Note 6)
Sourcing from 0µA to –200µA
q
q
q
q
q
q
q
q
q
q
q
q
ELECTRICAL CHARACTERISTICS
MIN
398
–0.5
397
–0.75
396
–1
394
–1.5
1.4
TYP
400
400
400
400
MAX
402
0.5
403
0.75
404
1
406
1.5
18
6
900
7.5
1130
8.5
1280
UNITS
mV
%
mV
%
mV
%
mV
%
V
mV
ppm/V
mV
ppm/V
mV
ppm/V
mV
ppm/mA
mV
ppm/mA
mV
ppm/mA
mV
ppm/mA
ppm/°C
6650f
–0.04
500
–0.2
2500
–0.4
5000
1
12500
2
20000
Sinking from 0µA to 200µA
q
q
0.24
3000
T
C
Output Voltage Temperature
Coefficient (Note 10)
q
30
2
U
W
U
U
W W
W
LT6650
The
q
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 5V, C
IN
= 1µF, FB = OUT, no DC load, C
L
= 1µF, unless
otherwise noted.
SYMBOL
∆V
DO
PARAMETER
Dropout Voltage (Note 7)
CONDITIONS
Referred to V
IN
= 1.8V, V
OUT
= 1.4V
(R
F
= 100k, R
G
= 39.2k)
∆V
OUT
= –0.1%, I
OUT
= 0µA
q
ELECTRICAL CHARACTERISTICS
MIN
TYP
MAX
UNITS
75
165
q
100
150
250
350
–150
0
mV
mV
mV
mV
mV
mV
mA
mA
∆V
OUT
= –0.1%, I
OUT
= –200µA Sourcing
∆V
OUT
= –0.1%, I
OUT
= 200µA Sinking (Note 11)
q
–300
5
9
5.6
q
I
SC
I
IN
Short-Circuit Output Current
Supply Current
V
OUT
Shorted to GND
V
OUT
Shorted to V
IN
11
14
12
15
10
15
30
µA
µA
µA
µA
nA
nA
nA
ms
µV
P-P
µV
RMS
mV
ppm
mV
ppm
V
IN
= 18V
q
5.9
I
FB
FB Pin Input Current
V
FB
= V
OUT
= 400mV
1.2
LT6650CS5, LT6650IS5
LT6650HS5
q
q
T
ON
e
n
V
HYS
Turn-On Time
Output Noise (Note 8)
Hysteresis (Note 9)
C
LOAD
= 1µF
0.1Hz
≤ ƒ ≤
10Hz
10Hz
≤ ƒ ≤
1KHz, I
OUT
= –200µA Sourcing
∆T
= 0°C to 70°C
∆T
= –40°C to 85°C
q
q
q
q
0.5
20
23
0.1
250
0.24
600
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2:
The FB pin is protected by an ESD diode to the ground. If the FB
input voltage exceeds –0.3V below ground, the FB input current should be
limited to less than 10mA. If the FB input voltage is greater than 5V, the FB
input current is expected to meet specified performance from Typical
Performance Characteristics but is not tested or QA sampled at this
voltage.
Note 3:
If the part is operating at temperatures above 85°C, it is
recommended to enhance the stability margin by using an output
capacitor greater than 10µF or a series RC combination having a 100µs
equivalent time constant. See Application section for details.
Note 4:
If the part is stored outside of the specified temperature range, the
output voltage may shift due to hysteresis.
Note 5:
ESD (Electrostatic Discharge) sensitive devices. Extensive use of
ESD protection devices are used internal to the LT6650; however, high
electrostatic discharge can damage or degrade the device. Use proper ESD
handling precautions.
Note 6:
Load regulation is measured on a pulse basis from no load to the
specified load current. Output changes due to die temperature change
must be taken into account separately.
Note 7:
Dropout Voltage is (V
IN
– V
OUT
) when V
OUT
falls to 0.1% below its
nominal value at V
IN
= 1.8V.
Note 8:
Peak-to-Peak noise is measured with a single pole highpass filter
at 0.1Hz and a 2-pole lowpass filter at 10Hz. The unit is enclosed in a still
air environment to eliminate thermocouple effects on the leads. The test
time is 10 seconds.
Note 9:
Hysteresis in the output voltage is created by package stress that
differs depending on whether the IC was previously at a higher or lower
temperature. Output voltage is always measured at 25°C, but the IC is
cycled to 85°C or –40°C before a successive measurement. Hysteresis is
roughly proportional to the square of the temperature change.
Note 10:
Temperature coefficient is measured by dividing the change in
output voltage by the specified temperature range.
Note 11:
This feature guarantees the shunt mode operation of the device.
6650f
3
LT6650
TYPICAL PERFOR A CE CHARACTERISTICS
Output Voltage Temperature
Drift
404
403
402
OUTPUT VOLTAGE (mV)
OUTPUT VOLTAGE (mV)
401
400
399
V
IN
= 18V
398
397
396
–60 –40 –20 0 20 40 60 80 100 120
TEMPERATURE (°C)
6650 G01
TYPICAL PART
SUPPLY CURRENT (µA)
402
V
IN
= 1.4V
V
IN
= 5V
Supply Current vs Input Voltage
10
125°C
OUTPUT VOLTAGE (mV)
8
402
T
A
= 125°C
401
400
399
398
T
A
= –55°C
T
A
= 25°C
OUTPUT VOLTAGE (mV)
SUPPLY CURRENT (µA)
6
25°C
–55°C
4
2
0
0
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
INPUT VOLTAGE (V)
6650 G04
Load Regulation (Sourcing)
0
–10
OUTPUT VOLTAGE CHANGE (µV)
–20
–30
–40
–50
–60
–70
–80
–90
–100
10
100
OUTPUT CURRENT (µA)
1000
6650 G07
TYPICAL PART
V
IN
= 5V
OUTPUT VOLTAGE CHANGE (µV)
25°C
125°C
–55°C
800
700
600
500
400
300
200
100
0
10
100
OUTPUT CURRENT (µA)
1000
6650 G08
INPUT-OUTPUT VOLTAGE (mV)
4
U W
(See Applications, Figure 1)
Output Voltage Temperature
Drift
403
THREE PARTS
V
IN
= 5V
10
Supply Current vs Input Voltage
8
125°C
401
6
25°C
4
–55°C
2
400
399
398
–60 –40 –20 0 20 40 60 80 100 120
TEMPERATURE (°C)
6650 G02
0
0
2
4
6 8 10 12 14 16 18 20
INPUT VOLTAGE (V)
6650 G03
Line Regulation
404
403
404
403
402
401
400
399
Line Regulation
T
A
= –55°C
T
A
= 25°C
T
A
= 125°C
2
4
6
8
10 12 14
INPUT VOLTAGE (V)
16
18
398
0.8
1.0
1.4
1.2
1.6
INPUT VOLTAGE (V)
1.8
2.0
6650 G06
6550 G05
Load Regulation (Sinking)
1000
900
TYPICAL PART
V
IN
= 5V
500
Minimum Input-Output Voltage
Differential (Sourcing)
V
OUT
= 1.425V - TYP (RF = 100k, RG = 39.2k)
0.1% V
OUT
400
125°C
300
25°C
–55°C
–55°C
25°C
125°C
200
100
0
10
100
OUTPUT CURRENT (µA)
1000
6650 G09
6650f
LT6650
TYPICAL PERFOR A CE CHARACTERISTICS
Minimum Input-Output Voltage
Differential (Sinking)
0
INPUT-OUTPUT VOLTAGE (mV)
V
OUT
= 1.425V - TYP (RF = 100k, RG = 39.2k)
0.1% V
OUT
OUTPUT CURRENT (mA)
–100
–55°C
–200
25°C
10
8
6
4
125°C
25°C
OUTPUT CURRENT (mA)
–300
–400
125°C
–500
10
100
OUTPUT CURRENT(µA)
1000
6650 G10
FB Pin Current vs FB Pin Voltage
10
V
FB
≠
V
OUT
8 CURRENT IS POSITIVE WHEN
IT ENTERS THE DEVICE
6
FB PIN CURRENT (nA)
FB PIN CURRENT (nA)
4
2
0
–2
–4
–6
–8
–55°C
125°C
GAIN (dB)
25°C
0.8
1.0
–10
–0.6 –0.4 –0.2 0 0.2 0.4 0.6
FB PIN VOLTAGE (V)
Output Noise 0.1Hz to 10Hz
V
IN
= 5V
NOISE LEVEL (µV/√Hz)
15
INTEGRATED NOISE (µV
RMS
)
OUTPUT NOISE (5µV/DIV)
0
1
2
3
4 5 6
TIME (s)
7
U W
6650 G13
(See Applications, Figure 1)
Output Short Circuit Current vs
Input Voltage
14
12
25°C
10
8
6
4
2
125°C
–55°C
OUTPUT SHORTED TO V
IN
Output Short Circuit Current vs
Input Voltage
14
12
OUTPUT SHORTED TO GND
–55°C
2
0
2
4
6 8 10 12 14 16 18 20
INPUT VOLTAGE (V)
6650 G11
0
2
4
6 8 10 12 14 16 18 20
INPUT VOLTAGE (V)
6650 G12
FB Pin Current vs FB Pin Voltage
10
V
FB
≠
V
OUT
CURRENT IS POSITIVE WHEN
IT ENTERS THE DEVICE
125°C
1
120
100
80
60
40
20
Gain and Phase vs Frequency
120
100
80
GAIN
PHASE
60
40
20
0
–20
1
10
FREQUENCY (kHz)
–40
100
6650 G15
PHASE (DEG)
0.1
25°C
0.01
1
3
5
–55°C
7
9 11 13 15
FB PIN VOLTAGE (V)
17
19
0 T = 25°C
A
UNITY GAIN
–20 R = 2k
L
C
L
= 1µF
–40
0.1
0.01
6650 G14
Output Voltage Noise Spectrum
20
V
IN
= 5V
C
L
= 1µF
100
Integrated Noise 10Hz to 1kHz
V
IN
= 5V
C
L
= 1µF
I
OUT
= –200µA
10
I
OUT
= 0µA
5
I
OUT
= –40µA
0
I
OUT
= –200µA
10
8
9
10
10
100
1k
FREQUENCY (Hz)
10k
6650 G17
1
10
100
FREQUENCY (Hz)
1k
6650 G18
6650 G16
6650f
5
