MAX9989 Datasheet, PDF (1/12 Pages) Maxim Integrated Products – +14dBm to +20dBm LO Buffers with ±1dB Variation

19-2486; Rev 0; 7/02
+14dBm to +20dBm LO Buffers
with ±1dB Variation
General Description
The MAX9989 and MAX9990 LO buffers provide the high
output (+14dBm to +20dBm) necessary to drive the LO
inputs of high-linearity passive mixers, while offering 40dB
reverse isolation to prevent LO pulling. The MAX9989 is
internally matched for the cellular/GSM bands, and the
MAX9990 is matched for the DCS/PCS/UMTS bands.
The Typical Application Circuit provides a nominal
+17dBm output power with ±1dB variation over supply,
temperature, and input power. With two optional resis-
tors, the output power can be precision set from
+14dBm to +20dBm. The devices offer more than 35dB
main driver output to PLL amp output isolation. Each
device is offered in a 5mm ✕ 5mm 20-pin thin QFN
package with exposed paddle.
Applications
Cellular/GSM/DCS/PCS/UMTS Base Station
Tx/Rx LO Drives
Coherent Receivers
ISM Wireless LAN
Wireless Local Loop
Local Multipoint Distribution Service
Point-to-Point Systems
Features
o ±1dB Output Power Variation
o +14dBm to +20dBm Adjustable Output Power
o 40dB Reverse Isolation
o Better Than 35dB Main Driver Output to PLL Amp
Output Isolation
o Low Output Noise: -170dBc/Hz at +17dBm
o 110mA Supply Current at +17dBm
o ESD Protection
o Isolated PLL Output (+3dBm)
Ordering Information
PART
TEMP
RANGE
PIN-
FREQUENCY
PACKAGE RANGE (MHz)
MAX9989ETP
-40°C to +85°C
20 Thin
QFN-EP*
700 to 1100
MAX9990ETP -40°C to +85°C 20 QFN-EP* 1500 to 2200
*EP = Exposed paddle.
Typical Application Circuit/Pin Configuration appears at end of data sheet.
Typical Operating Circuit and Block Diagram
TO PLL
PRESCALER
RF LO
OUTPLL
(+3dBm)
IN
(+7dBm)
PLL BUFFER
MAX9989
MAX9990
INPUT AMP
OUTPUT AMP
RF INPUT
OUTLO
(+17dBm)
IF OUTPUT
BIAS
BIASIN
BIASOUT
BIAS
CONTROL
NETWORK
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