LTC1043

7

1043fa

Figure 4. Individual Switch Charge Injection

vs Input Voltage

Figure 5. Printed Circuit Board Layout

Showing Shielding the Sampling Capacitor

Figure 6. Internal Oscillator

APPLICATIO S I FOR ATIO

0

0

2

4

6

8

48

12

16

LTC1043 • AI04

10

12

26

10

14

V+ = 15V

V– = 0V

V+ = 10V

V– = 0V

V+ = 5V

V– = 0V

LTC1043 • AI05

1

2

3

OUTSIDE FOIL

PRINTED CIRCUIT

BOARD AREA

LTC1043

recover from the latch mode when the input drops 3V to 4V

below the voltage value which caused the latch. For

instance, if an external resistor of 200Ω is connected in

series with an input pin, the input can be taken 1.3V above

the supply without latching the IC. The same applies for the

The Cosc pin can be used with an external capacitor, Cosc,

connected from Pin 16 to Pin 17, to modify the internal

oscillator frequency. If Pin 16 is floating, the internal 24pF

capacitor, plus any external interpin capacitance, set the

oscillator frequency around 190kHz with ±5V supply. The

typical performance characteristics curves provide the

necessary information to set the oscillator frequency for

various power supply ranges. Pin 16 can also be driven

with an external clock to override the internal oscillator.

Although standard 7400 series CMOS gates do not

guarantee CMOS levels with the current source and sink

requirements of Pin 16, they will in reality drive the Cosc

pin. CMOS gates conforming to standard B series output

drive have the appropriate voltage levels and more than

enough output current to simultaneously drive several

trigger (Figure 6) are given below.

LTC1043 * AI06

24pF

17

16

4

(EXTERNAL)

(24pF)

V+

V–

38µF

TO CLK GENERATOR

SUPPLY

TRIP LEVELS