OUT+

OUT-

RSSI_EB

VCC_IN

FILTER1/2

GND

RF

IN

TIA

Voltage Amplifier

AGCandDC

Offset

Cancellation

CML OutputBuffer

RSSI_IB

220 W

ToTIA

ToVoltage AmplifierandOutputBuffer

VCC_OUT

ONET8531T

SLLS891B

– FEBRUARY 2008 – REVISED AUGUST 2011

www.ti.com

These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam

during storage or handling to prevent electrostatic damage to the MOS gates.

BLOCK DIAGRAM

Figure 1 shows an ONET8531T block diagram. The ONET8531T consists of the signal path, supply filters, a

control block for DC input bias, automatic gain control (AGC), and a received signal strength indicator (RSSI).

The RSSI provides the bias for the TIA stage and the control for the AGC.

The signal path consists of a transimpedance amplifier stage, a voltage amplifier, and a CML output buffer. The

The DC input bias circuit and automatic gain control use internal low pass filters to cancel the DC current on the

input and to adjust the transimpedance amplifier gain. Additionally, the chip provides circuitry to monitor the

received signal strength.

Figure 1. ONET8531T Block Diagram

2

Copyright

© 2008–2011, Texas Instruments Incorporated