Datasheet

LT1011/LT1011A
12
1011afc
TYPICAL APPLICATIONS
4-Digit (10,000 Count) A/D Converter
Capacitance to Pulse Width Converter
+
+
–
+
LT1011
5V
GAIN ADJ
D1
2
8
4
D3
†
D2
†
10μF
†
1011 TA20
10μF
†
6
0.01μF
R5
4.7k
R3
86.6k
TTL OR CMOS
(OPERATING
ON 5V)
OUTPUT
1μs/pF
1
7
3
C**
R2
100k
R1
5k
T
H
≥ [C
MAX
(pF)][1μs/pF]
T
L
≥ 10 • C
MAX
• (1μs/pF)
*PW = (R2 + R3)(C)
** TYPICAL 2 SECTIONS OF 365pF VARIABLE
CAPACITOR WHEN USED AS SHAFT ANGLE
INDICATION
†
THESE COMPONENTS MAY BE ELIMINATED IF
NEGATIVE SUPPLY IS AVAILABLE (–1V TO –15V)
LT1011 IS ≈6pF. THIS IS AN OFFSET TERM.
, INPUT CAPACITANCE OF

R1 + R4
R1
–
+
LT1011
7
6
1
8
2
3
4
–15V
15V
15V
INPUT
0V TO 10V
C5
0.01μF
R5
4.7k
R7
22Ω
R11
6.8K
CLOCK
1MHz
5V
R6
4.7K
R2
18k
R1
1k
ZERO
TRIM
R9
3.65k
R8
3k
R10
1k
FULL-SCALE
TRIM
R3
3.9k
R4
5.6k
C1*
0.1μF
C3
0.1μF
2N3904
1011 TA19
R12
6.8k
C6
50pF
C2**
15pF
D2
D1
D3
D4
LM329
*
**
ALL DIODES: 1N4148
POLYSTYRENE
NPO
START
≥12ms
15V
6
3
7
4
8
1
2
5
–15V
5V
C4
0.01μF
15V
LF398
OUTPUT = 1 COUNT
PER mV, f = 1MHz