鉁?/div>
5mm), 0.8mm Height (max)
MAX1958/MAX1959
The MAX1958/MAX1959 power amplifier (PA) power-
management ICs (PMICs) integrate an 800mA, dynami-
cally adjustable step-down converter, a 5mA Rail-to-
Rail
廬
operational amplifier (op amp), and a precision
temperature sensor to power a heterojunction bipolar
transistor (HBT) PA in W-CDMA and N-CDMA cell
phones.
The high-efficiency, pulse-width modulated (PWM), DC-
to-DC buck converter is optimized to provide a guaran-
teed output current of 800mA. The output voltage is
dynamically controlled to produce any fixed-output volt-
age in the range of 0.75V to 3.4V (MAX1958) or 1V to
3.6V (MAX1959), with settling time less than 30碌s for a
full-scale change in voltage and current. The 1MHz PWM
switching frequency allows the use of small external
components while pulse-skip mode reduces quiescent
current to 190碌A(chǔ) with light loads. The converter utilizes a
low on-resistance internal MOSFET switch and synchro-
nous rectifier to maximize efficiency and minimize
external component count. The 100% duty-cycle opera-
tion allows for an IC dropout voltage of only 130mV (typ)
at 600mA load.
The micropower op amp is used to provide bias to the
HBT PA to maximize efficiency. The amplifier features
active discharge in shutdown for full PA bias control. It
has 5mA rail-to-rail drive capability, 800kHz gain-band-
width product, and 120dB open-loop voltage gain.
The precision temperature sensor measures tempera-
tures between -40擄C to +125擄C, with linear tempera-
ture-to-voltage analog output characteristics.
The MAX1958/MAX1959 are available in a 20-pin 5mm
鉁?/div>
5mm thin QFN package (0.8mm max height).
Ordering Information
PART
MAX1958ETP
MAX1959ETP
TEMP RANGE
-40擄C to +85擄C
-40擄C to +85擄C
PIN-PACKAGE
20 Thin QFN-EP*
20 Thin QFN-EP
*EP
= Exposed paddle.
Pin Configuration
SHDN1
V
CC
Applications
W-CDMA and N-CDMA Cellular Phones
Wireless PDAs and Modems
TOP VIEW
20
19
18
17
AOUT
SHDN2
AGND
TOUT
REF
1
2
3
4
5
10
6
7
8
9
16
15
14
INP
IN+
IN-
PWM
INP
IN
LX
PGND
MAX1958/
MAX1959
13
12
11
SHDN3
AGND
COMP
Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd.
THIN QFN
5mm x 5mm
________________________________________________________________
Maxim Integrated Products
OUT
ADJ
Typical Operating Circuit and Functional Diagram appear at
end of data sheet.
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim鈥檚 website at www.maxim-ic.com.
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