LTC6943
Micropower, Dual Precision
Instrumentation Switched
Capacitor Building Block
FEATURES
DESCRIPTIO
Low Power, I = 60A(Max) The LTC 6943 is a monolithic, charge-balanced, dual
S
Robust, Latch Up Proof switched capacitor instrumentation building block. A pair
Instrumentation Front End with 120dB CMRR of switches alternately connects an external capacitor to
Precise, Charge-Balanced Switching an input voltage and then connects the charged capacitor
Operates from 5V to 18V across an output port. The internal switches have a
Internal or External Clock break-before-make action. An internal clock is provided
Operates up to 5MHz Clock Rate and its frequency can be adjusted with an external
Two Independent Sections with One Clock capacitor. The LTC6943 can also be driven with an external
Tiny SSOP-16 Package CMOS clock.
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APPLICATIO S The LTC6943, when used with low clock frequencies,
provides ultra precision DC functions without requiring
Ultra Precision Voltage Inverters, Multipliers
precise external components. Such functions are
and Dividers
differential voltage to single-ended conversion, voltage
VF and FV Converters
inversion, voltage multiplication and division by 2, 3, 4, 5,
Sample-and-Hold
etc.
Current Sources
The LTC6943 is manufactured using Linear Technologys
Precision Instrumentation Amplifiers
TM
enhanced LTCMOS silicon gate process, and it is func-
, LTC and LT are registered trademarks of Linear Technology Corporation.
LTCMOS is a trademark of Linear Technology Corporation.
tionally compatible with the LTC1043.
TYPICAL APPLICATIO
Precision Voltage Controlled Current Source
with Ground Referred Input and Output
5V
Precision Current Sensing in Supply Rails
INPUT 3
5
+
0V TO 3.7V
1
E
LTC2050
I
4 POSITIVE OR
2
NEGATIVE RAIL
R
SHUNT
0.68F
1/2 LTC6943
11 12
5V
1k
3
10
1/2 LTC6943
7 6
E
1F
1F E I =
R
SHUNT
9
9
1F 1F 1k
10
6 7
12 11
V
IN
I =
OUT
14 15
1000
0.01F
15 14
0.001F
6943 TA01b
OPERATES FROM A
SINGLE 5V SUPPLY
6943 TA01a
6943f
1
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ULTC6943
UUW
ABSOLUTE AXI U RATI GS PACKAGE/ORDER I FOR ATIO
(Note 1)
ORDER PART
Supply Voltage ........................................................ 18V
TOP VIEW
+
NUMBER
+
Input Voltage at Any Pin .......... 0.3V V V + 0.3V
CB 1
IN 16 S3B
Operating Temperature Range
CB 2 15
V
LTC6943CGN
+
(Note 2) ............................................ 40C to 125C V 3 14
C
OSC
LTC6943IGN
S2B 4 13
Specified Temperature Range S4B
LTC6943HGN
S1B 5 12
S4A
(Note 2) .............................................40C to 125C
S1A 6 11
S3A GN PART
Storage Temperature Range ................. 65C to 150C
S2A 7 10
CA
MARKING
Lead Temperature (Soldering, 10 sec).................. 300C
+
SHA 8 9
CA
6943C
GN PACKAGE
6943I
16-LEAD NARROW PLASTIC SSOP
T = 125C, = 110C/W
JMAX JA
6943H
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
The denotes specifications which apply over the full operating temperature
+
range, otherwise specifications are at T = 25C. V = 10V, V = 0V
A
LTC6943C
LTC6943I LTC6943H
SYMBOL PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS
I Power Supply Current Pin 14 Connected High or Low 40 60 40 60 A
S
90 90 A
C (Pin 14 to V ) = 100pF 80 150 80 150 A
OSC
170 170 A
I OFF Leakage Current Any Switch, Test Circuit 1 (Note 3) 6 100 6 100 pA
I
40 200 nA
R ON Resistance Test Circuit 2, V = 7V, 1 = 0.5mA 240 400 240 400
ON IN
+
V = 10V, V = 0V 700 700
R ON Resistance Test Circuit 2, V = 3.1V, 1 = 0.5mA 400 700 400 700
ON IN
+
V = 5V, V = 0V 11k
f Internal Oscillator Frequency C (Pin 14 to V ) = 0pF 185 185 kHz
OSC OSC
C (Pin 14 to V ) = 100pF 20 30 50 20 30 50 kHz
OSC
Test Circuit 3 12 75 10 75 kHz
+
I Pin Source or Sink Current Pin 14 at V or V 40 70 40 70 A
OSC
100 100 A
Break-Before-Make Time 25 25 ns
Clock to Switching Delay C Pin Externally Driven 75 75 ns
OSC
f Maximum External CLK Frequency C Pin Externally Driven with CMOS Levels 5 5 MHz
M OSC
+
CMRR Common Mode Rejection Ratio V = 5V, V = 5V, 5V < V < 5V 120 120 dB
CM
DC to 400Hz
Note 1: Absolute Maximum Ratings are those values beyond which the life to 85C but it is not tested or QA sampled at these temperatures.
of a device may be impaired.
The LTC6943IGN is guaranteed to meet specified performance from 40C
Note 2: All versions of the LTC6943 are guaranteed functional over the to 85C. The LTC6943HGN is guaranteed to meet specified performance
operating temperature range of 40C to 125C. The LTC6943CGN is from 40C to 125C.
guaranteed to meet 0C to 70C specifications and is designed,
Note 3: OFF leakage current at 25C is guaranteed by design and it is not
characterized and expected to meet the specified performance from 40C
100% tested in production.
6943f
2
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