AS2702 – AS-Interface Slave IC

Revision 1.3, 21-Aug-08

Page 5 of 13

Buffer Pin CDC

An external buffer capacitor with a recommended value of 100nF should be connected to this pin to ensure a sufficiently high input

impedance Z at power supply pin LTGP.

Voltage at this pin can be as high as VLTGP.

Nom. 24V Power Supply Output UOUT

The supply output voltage at UOUT is directly derived from VLTGP and regulated to a level with an offset of about -6V relative to

VLTGP.

UOUT provides bias to the sensors and actuators circuitry connected to the slave device as well as to the LEDs connected to

outputs LED1 and LED2.

UOUT is equipped with a thermal overload protection, which foresees that VUOUT is switched off as soon as the slave device’s

substrate temperature TJ passes a threshold value in the range of (155

±20)°C.

After TJ has come down and has passed a temperature threshold about (15

±5)°C lower than (155 ±20)°C and after a consecutive

minimum delay time of 1s has elapsed, VUOUT is switched on again.

Symbol

Parameter

Min

Max

Unit

Note

VUOUT

Power supply output voltage

VLTGP - 6.3V

VLTGP - 5.3V

V

IUOUT

Load current

50

mA

1

VCOMOFF UOUT voltage level

9.5

10.5

V

below which data transmission is inhibited

CUOUT

Buffer capacitor

10

µF

2

Notes:

1

In case IUOUT >40mA and presence of sin2-data pulses on LTGP with VSIG >3V, VUOUT may drop as much as 1V below it’s

level in unloaded condition

2

Electrolytic and rf filter capacitor in parallel

Nom. 5V Power Supply Output U5R

The voltage at U5R is derived from the voltage present at UOUT, as long as UOUT is not switched off due to overload. In the latter

case U5R is derived from an alternative voltage out of the UOUT voltage regulator, which is more or less similar to VUOUT in non

switched off condition of UOUT. As a result VU5R is not affected by overload condition at UOUT and will remain.

Symbol

Parameter

Min

Max

Unit

VU5R

Power supply output voltage

4.85

5.15

V

IU5R

Load current

1

mA

CU5R

Buffer capacitor

470

nF

Oscillator Pins OSC1 and OSC2

The only component to be connected to these pins is a quartz crystal with a resonance frequency of 5.333333 MHz (AS-Interface

quartz crystal).

Symbol

Parameter

Min

Max

Unit

CX2

Stray capacitance

10

pF