1

Rev. 5/14/03

SP8034A APC Amplifier with Integrated Photodetector

© Copyright 2003 Sipex Corporation

250 V/µs APC Amplifier with Integrated Photodiode

and Gain Adjust Capability

SP8034A

FEATURES

■ Slew Rate of 250V/us

■ 7ns Settling Time to 1% for 1.5V Step

■ 10 mV Output Offset Voltage

■ 20uV/°C Output Offset Drift

■ Digital Gain Select

■ +/- 6 dB External Gain Adjust

®

Figure 1. Functional Diagram

DESCRIPTION

TheSP8034ArepresentsthenextgenerationAPCamplifierwithintegratedphotodetector.Thisdevice

monitors the light intensity of the laser diode in CD-R, CD-RW, DVD-R, DVD-RW and DVD-RAM

assemblies by sensing the laser power with an integrated photodiode. The amplified signal from the

APC contains the laser power information. This signal is subsequently fed back to the laser diode driver

to control its power. The on-chip photodetector transforms incident light into a proportional current. This

current is then converted to a voltage through a transimpedance amplifier. Adjustable gain is provided

inthetransimpedanceamplifierbymeansofagaincontrolloopthatiscontrolledbyanexternalresistor.

The external resistor is not part of the signal path, which greatly reduces the effects of all parasitic

capacitances and inductances on the flex cable at these pins. The signal is buffered to provide reactive

load drive capability.

The SP8034A achieves an unparalleled level of performance by combining excellent DC stability and

low noise with outstanding AC performance. This level of performance is achieved using a proprietary

fully complementary BiCMOS process with fully integrated, on-board photodetectors.

The SP8034A is offered with a nominal gain of 2000V/W and is packaged in a 3.0mm x 3.5mm, 8 lead

COB package.

1

2

3

4

8

7

6

5

V

CC

GAIN SEL

RG

COM

GND

V

OUT

V

REF

R

GAIN2

R

GAIN1

SP8034A

8 Pin COB

GND

Rg2

Rg1

TIA

6k

Gain Control

Buffer

Gain Select

R2

R1

R2

R1

6000

2000

6000

2000

PRELIMINARY