January, 2000
PRELIMINARY DATASHEET
The ML2731 is a power amplifier (PA) bias controller with
support circuits for a typical radio transceiver. The IC
integrates a PA bias controller, a PA DC switch, a crystal
oscillator circuit, a negative voltage generator and two
voltage regulators. It can be used with GaAs FETs and
silicon bipolar devices.
Micro Linear's ML2731, along with the ML2712 and the
ML2713, form a complete transceiver solution for the 2.4
GHz IEEE802.11 communication standard, as well as
other wireless ISM communication products.
In addition to supporting Micro Linear's transceiver chip
set, the ML2731 can stand alone as:
A compact bias voltage controller
A compact negative voltage generator
A compact crystal oscillator
n Sets PA current and power output using a bias control
loop
n Integrates a PA DC supply switch
n Prevents PA power-on if negative voltage is not present
n Integrates all circuits needed for supporting a crystal
oscillator with 10MHz to 40MHz frequency range
n Incorporates a fast starting, high switching frequency,
negative voltage generator requiring only small
ceramic capacitors
n Contains voltage regulators for an oscillator, a negative
voltage generator and a 50mA 3.0V LDO output
n Requires less than 1mA of current when powered down
n Supply voltage ranges from 3.3V to 5.5V
GENERAL DESCRIPTION
ML2731 PA Bias Controller
FEATURES
SIMPLIFIED BLOCK DIAGRAM
APPLICATIONS
n Cellular and Cordless Radios
n WLAN Radios
n Radios with GaAs FET Power Amplifiers
n Fixed and Mobile radio transceivers
PRELIMINARY
Voltage
Regulator
Sine & square
wave drivers
CLKO
REGO
Bias Control
VPA
VBIAS
Baseband Controller
(e.g. MSM7730B)
Crystal
PDN
XOUT
XIN
PAEN
NEGEN
ICON
SINO
Crystal
Oscillator
VNEG
Negative voltage
generator
C1
C2
GaAs FET Power Amplifier
PA on/off switch
and current sense
ML2712
ML2713
Radio
ML2731
ML2731
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January, 2000
PRELIMINARY DATASHEET
PRELIMINARY
TABLE OF CONTENTS
2000. Micro Linear is a registered trademark of Micro Linear Corporation. All other trademarks are the property of their
respective owners.
Products described herein may be covered by one or more of the following U.S. patents: 4,897,611; 4,964,026; 5,027,116;
5,281,862; 5,283,483; 5,418,502; 5,508,570; 5,510,727; 5,523,940; 5,546,017; 5,559,470; 5,565,761; 5,592,128; 5,594,376;
5,652,479; 5,661,427; 5,663,874; 5,672,959; 5,689,167; 5,714,897; 5,717,798; 5,742,151; 5,747,977; 5,754,012; 5,757,174;
5,767,653; 5,777,514; 5,793,168; 5,798,635; 5,804,950; 5,808,455; 5,811,999; 5,818,207; 5,818,669; 5,825,165; 5,825,223;
5,838,723; 5.844,378; 5,844,941. Japan: 2,598,946; 2,619,299; 2,704,176; 2,821,714. Other patents are pending.
Micro Linear makes no representations or warranties with respect to the accuracy, utility, or completeness
of the contents of this publication and reserves the right to make changes to specifications and product
descriptions at any time without notice. No license, express or implied, by estoppel or otherwise, to any
patents or other intellectual property rights is granted by this document. The circuits contained in this
document are offered as possible applications only. Particular uses or applications may invalidate some of
the specifications and/or product descriptions contained herein. The customer is urged to perform its own
engineering review before deciding on a particular application. Micro Linear assumes no liability
whatsoever, and disclaims any express or implied warranty, relating to sale and/or use of Micro Linear
products including liability or warranties relating to merchantability, fitness for a particular purpose, or
infringement of any intellectual property right. Micro Linear products are not designed for use in medical,
life saving, or life sustaining applications.
WARRANTY
General Description ................................................................................................................................................... 1
Simplified Block Diagram .......................................................................................................................................... 1
Features ...................................................................................................................................................................... 1
Applications ............................................................................................................................................................... 1
Block Diagram ........................................................................................................................................................... 3
Pin Configuration ....................................................................................................................................................... 4
Pin Descriptions ......................................................................................................................................................... 4
Functional Description ............................................................................................................................................... 6
Introduction .............................................................................................................................................................. 6
External Interfaces ................................................................................................................................................... 6
Mode Control ........................................................................................................................................................... 6
Description Of Operation ........................................................................................................................................... 6
Crystal Oscillator ..................................................................................................................................................... 7
Negative Voltage Generator ..................................................................................................................................... 7
Absolute Maximum Ratings ........................................................................................................................................ 11
Electrical Tables ......................................................................................................................................................... 11
Electrical Characteristics ............................................................................................................................................ 11
Operating Conditions ................................................................................................................................................. 11
Physical Dimensions .................................................................................................................................................. 12
Ordering Information .................................................................................................................................................. 12
ML2731
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January, 2000
PRELIMINARY DATASHEET
PRELIMINARY
PIN DESCRIPTIONS
PIN CONFIGURATION
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
TOP VIEW
ML2731
16-Pin TSSOP (T16)
SINO
VCC
REGO
VBIAS
ICON
PAEN
NEGEN
CLKO
XOUT
XIN
PDN
VPA
C1
C2
VNEG
GND
1
SINO
O (ANLG)
Sine wave output. This pin is a low impedance output capable of
driving a 2k
W load. The signal is sourced with either a crystal
interfaced with on-chip components through XOIN (pin 15) and XOUT
(pin 16) or with a completely external oscillator through pin 15.
Taking PDN (pin 14) high switches off output
2
VCC
O (ANLG)
DC power supply
3
REGO
O (ANLG)
IC regulator output. This is the output from the on IC regulator. It is
disabled in the SLEEP mode of operation and enabled in all other
modes. The nominal output voltage is 2.9 V and it has a low
impedance output which can source up to 50mA
4
VBIAS
O (ANLG)
PA bias voltage output. This output has limited drive capability of 3mA
and is intended to drive the gate or bias of the PA
5
ICON
I (ANLG)
Reference current input. Used by the PA bias control loop to set the PA
current level. This input appears as a virtual ground
6
PAEN
I (CMOS)
PA Enable. Transitions from high to low on this pin activate the PA
current ramp up function, switch the PA voltage supply switch on and
enable the PA bias control loop. Transitions from low to high activate
the PA current ramp down function and switch the PA voltage supply
off
7
NEGEN
I (CMOS)
Negative Voltage Enable. In conjunction with PDN and PAEN, NEGEN
controls the operational mode of the IC and enables the negative
voltage generator circuits
8
CLKO
I (CMOS)
Clock output. The frequency is set with either a crystal interfaced with
on-chip components through XOIN (pin 15) and XOUT (pin 16) or with
a completely external oscillator through pin 15. CLKO switches off
when device goes into SLEEP mode when PDN is taken high
9
GND
GND
Ground
10
VNEG
O (ANLG)
Negative regulator output. This pin is one of the outputs of the negative
switching regulator. A capacitor connected serves as a current
reservoir. Typically a 100nF capacitor is connected between pin 10
and GND
11
C2
O (ANLG)
Noise Shunt. Negative voltage generator capacitor connection. This
output of the negative switching regulator shunts regulator noise to
ground using a 100nF bypass capacitor
Pin #
Signal Name
I/O
Description
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