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db05175e_V3.01_preliminary_2017-07-06

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AS89000

V3.01

3 DESCRIPTION OF FUNCTION

The AS89000-devices are programmable gain transimpedance amplifiers1 with different

numbers of channels (AS89000 – 4 channels). There is one transimpedance amplifier per

channel between a current input IIN<X> and a voltage output2 VOUT<X>. Its transimpedance

is selectable in 8 stages. This adjustment can be effected by setting of digital inputs SW1, SW3

and SW4 and is valid for all channels simultaneously (chapter 2.2).

Also simultaneously valid for all channels is a compensation of the input capacitance of photo-

sensors for two possible frequency ranges (switchable by SW4, chapter 2.3).

The pins SW1, SW2, SW3 and SW4 are pull down inputs.

The second input of all transimpedance amplifiers is used for a common supply by a reference voltage

necessarily fed in through the pin VREF.

All channels are compensated for an external input capacitance of the photo-sensor of smaller than 80 pF

(SW4 = GND). The power supply for the AS89000-devices is typical 3 V to 5 V between VDD and GND.

The power down mode is adjusted by PD = VDD and switches off the functionality. In that case it must be

pointed out that the transimpedance resistor of stage 8 is between the particular inputs and outputs. The

amplifiers are switched off (tri-state).

4 ELECTRICAL CHARACTERISTICS

4.1 Maximum Conditions

Violations of absolute maximum conditions are not allowed under any circumstances, otherwise the IC can

be destroyed.

All voltages are referenced to GND = 0 V.

PARAMETER

NAME

MIN

MAX

UNIT

power supply

VDD

0.3

7.0

V

input and output voltages

 IC-pinning

0.3

VDD+0.3

V

power dissipation

POP

0.025

W

operating temperature

TOP

40

125

°C

storage temperature

TSTG

55

155

°C

weight

m



0,08

g

4.2 Operating Conditions

All voltages are referenced to GND = 0 V.

Table 5: Operating Conditions

PARAMETER

NAME

MIN

TYP

MAX

UNIT

CONDITIO

N

supply voltage

VDD

2.7

3 to 5

5.5

V

bias current AS89000

I(VDD)

2.5

4.0

mA

27°C,

VDD=5.5 V

1 work as inverted amplifiers

2 VOUT = VREF – IIn * R