General Description
The MAX1958/MAX1959 power amplifier (PA) power-
management ICs (PMICs) integrate an 800mA, dynami-
cally adjustable step-down converter, a 5mA Rail-to-
Rail
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 30s 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 190A 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 -40C to +125C, with linear tempera-
ture-to-voltage analog output characteristics.
The MAX1958/MAX1959 are available in a 20-pin 5mm
5mm thin QFN package (0.8mm max height).
Applications
W-CDMA and N-CDMA Cellular Phones
Wireless PDAs and Modems
Features
o Step-Down Converter
Dynamically Adjustable Output Voltage from
0.75V to 3.4V (MAX1958)
Dynamically Adjustable Output Voltage from
1V to 3.6V (MAX1959)
800mA Guaranteed Output Current
130mV IC Dropout at 600mA Load
Low Quiescent Current
190A (typ) in Skip Mode (MAX1958)
3mA (typ) in PWM Mode
0.1A (typ) in Shutdown Mode
1MHz Fixed-Frequency PWM operation
16% to 100% Duty-Cycle Operation
No External Schottky Diode Required
Soft-Start
o Operational Amplifier
5mA Rail-to-Rail Output
Active Discharge in Shutdown
800kHz Gain-Bandwidth Product
120dB Open-Loop Voltage Gain (R
L
= 100k
)
o Temperature Sensor
Accurate Sensor -11.7mV/C Slope
-40C to +125C-Rated Temperature Range
o 20-Pin Thin QFN (5mm
5mm), 0.8mm Height (max)
MAX1958/MAX1959
W-CDMA/N-CDMA Cellular Phone HBT PA
Management ICs
________________________________________________________________ Maxim Integrated Products
1
20
19
18
17
IN-
IN+
SHDN1
16
INP
V
CC
13
12
11
14
15
LX
IN
INP
PWM
PGND
4
3
2
1
TOUT
AGND
SHDN2
AOUT
5
REF
6
7
8
9
AGND
COMP
ADJ
SHDN3
10
OUT
MAX1958/
MAX1959
TOP VIEW
THIN QFN
5mm x 5mm
Pin Configuration
Ordering Information
19-2659; Rev 0; 10/02
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
PART
TEMP RANGE
PIN-PACKAGE
MAX1958ETP
-40
C to +85C
20 Thin QFN-EP*
MAX1959ETP
-40
C to +85C
20 Thin QFN-EP
Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd.
Typical Operating Circuit and Functional Diagram appear at
end of data sheet.
EVALUATION KIT
AVAILABLE
*EP = Exposed paddle.
MAX1958/MAX1959
W-CDMA/N-CDMA Cellular Phone HBT PA
Management ICs
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
IN, INP, OUT, ADJ, SHDN1, SHDN2,
SHDN3, PWM, V
CC
to PGND ...................................-0.3V to +6V
AGND to PGND .....................................................-0.3V to +0.3V
COMP, REF to AGND ....................................-0.3 to (V
IN
+ 0.3V)
IN+, IN-, AOUT, TOUT to AGND ................-0.3 to (V
VCC
+ 0.3V)
LX Current (Note 1).............................................................1.6A
Output Short-Circuit Duration.....................................Continuous
Continuous Power Dissipation (T
A
= +70C)
20-Pin Thin QFN 5mm x 5mm
(derate 20.8mW/C above +70C) .............................1670mW
Operating Temperature Range ...........................-40C to +85C
Junction Temperature ......................................................+150C
Storage Temperature Range .............................-65C to +150C
Lead Temperature (soldering, 10s) .................................+300C
ELECTRICAL CHARACTERISTICS (STEP-DOWN CONVERTER)
(V
INP
= V
IN
= V
VCC
= V
SHDN1
= 3.6V, V
PWM
= V
PGND
= V
AGND
= V
SHDN2
= V
SHDN3
= 0, V
ADJ
= 1.25V, COMP = IN- = IN+ = AOUT
= TOUT = unconnected, C
REF
= 0.1F, T
A
= 0C to +85C, V
OUT
for MAX1958 = 2.2V, V
OUT
for MAX1959 = 1.7V, unless otherwise
noted. Typical values are at T
A
= +25C.)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Supply Voltage Range
2.6
5.5
V
Undervoltage Lockout Threshold
Rising or falling, hysteresis is 1%
2.20
2.35
2.55
V
MAX1958, PWM = AGND
190
300
MAX1959, PWM = AGND
280
450
A
Quiescent Current
V
PWM
= V
IN
3
mA
MAX1958
295
550
Quiescent Current in Dropout
MAX1959
330
600
A
Shutdown Supply Current
V
SHDN1
= 0
0.1
6
A
ERROR AMPLIFIER
V
ADJ
= 1.932V, I
LOAD
= 0 to 600mA, V
PWM
= V
IN
= 3.8V
3.38
3.40
3.42
V
ADJ
= 0.426V, I
LOAD
= 0 to 30mA, V
PWM
= 0
0.739
0.750
0.761
OUT Voltage Accuracy
(MAX1958)
V
ADJ
= 0.426V, I
LOAD
= 0 to 30mA, V
PWM
= V
IN
= 4.2V
0.739
0.750
0.761
V
V
ADJ
= 2.2V, I
LOAD
= 0 to 600mA, V
PWM
= V
IN
= 4V
3.58
3.60
3.62
V
ADJ
= 0.9V, I
LOAD
= 0 to 30mA, V
PWM
= 0
0.985
1.00
1.015
OUT Voltage Accuracy
(MAX1959)
V
ADJ
= 0.9V, I
LOAD
= 0 to 30mA, V
PWM
= V
IN
= 4.2V
0.985
1.00
1.015
V
V
OUT
= 0.75V
2
4
6
OUT Input Current (MAX1958)
V
OUT
= 3.4V
11
17
25
A
V
OUT
= 1V
2.5
4.0
6.5
OUT Input Current (MAX1959)
V
OUT
= 3.6V
10
16
23
A
ADJ Input Current (MAX1958)
V
ADJ
= 0.426V to 1.932V
-150
+1
+150
nA
ADJ Input Current (MAX1959)
V
ADJ
= 0.9V to 2.2V
-150
+1
+150
nA
Positive COMP Output Current
(MAX1958)
V
ADJ
= 1V, V
OUT
= 1.5V, V
COMP
= 1.25V
-27
-14
-7
A
Positive COMP Output Current
(MAX1959)
V
ADJ
= 1V, V
OUT
= 1V, V
COMP
= 1.25V
-27
-14
-7
A
Note 1: LX has internal clamp diodes to PGND and INP. Applications that forward bias these diodes should take care not to exceed
the IC's package power dissipation limits.
MAX1958/MAX1959
W-CDMA/N-CDMA Cellular Phone HBT PA
Management ICs
_______________________________________________________________________________________
3
ELECTRICAL CHARACTERISTICS (STEP-DOWN CONVERTER) (continued)
(V
INP
= V
IN
= V
VCC
= V
SHDN1
= 3.6V, V
PWM
= V
PGND
= V
AGND
= V
SHDN2
= V
SHDN3
= 0, V
ADJ
= 1.25V, COMP = IN- = IN+ = AOUT
= TOUT = unconnected, C
REF
= 0.1F, T
A
= 0C to +85C, V
OUT
for MAX1958 = 2.2V, V
OUT
for MAX1959 = 1.7V, unless otherwise
noted. Typical values are at T
A
= +25C.)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Negative COMP Output Current
(MAX1958)
V
ADJ
= 1V, V
OUT
= 2V, V
COMP
= 1.25V
7
14
27
A
Negative COMP Output Current
(MAX1959)
V
ADJ
= 1V, V
OUT
= 1.4V, V
COMP
= 1.25V
7
14
27
A
REFERENCE
REF Output Voltage
1.225
1.250
1.275
V
REF Load Regulation
10A < I
REF
< 100A
2.50
6.25
mV
Undervoltage Lockout Threshold
Rising or falling, 1% hysteresis
0.85
1.00
1.10
V
Supply Rejection
2.6V < V
IN
< 5.5V
0.07
1.7
mV/V
CONTROLLER
I
LX
= 180mA, V
IN
= 3.6V
0.21
0.40
P-Channel On-Resistance
I
LX
= 180mA, V
IN
= 2.6V
0.25
0.5
I
LX
= 180mA, V
IN
= 3.6V
0.18
0.30
N-Channel On-Resistance
I
LX
= 180mA, V
IN
= 2.6V
0.21
0.35
Current-Sense Transresistance
0.5
V/A
P-Channel Current-Limit
Threshold
1.1
1.37
1.6
A
P-Channel Pulse-Skipping
Current Threshold
V
PWM
= 0
0.12
0.15
0.17
A
N-Channel Current-Limit
Threshold
V
PWM
= V
IN
-0.5
A
N-Channel Zero-Crossing
Comparator
V
PWM
= 0
20
mA
LX Leakage Current
V
IN
= 5.5V
-20.0
+0.1
+20.0
A
LX RMS Current
(Note 1)
1.0
A
Maximum Duty Cycle
100
%
V
PWM
= 0
0
Minimum Duty Cycle
V
PWM
= V
IN
= 4.2V
16
%
Oscillator Frequency
0.85
1.00
1.15
MHz
Thermal-Shutdown Threshold
Hysteresis = +15
C
160
C
LOGIC INPUTS (PWM,
SHDN1)
Logic Input High
2.6 V < V
IN
< 5.5 V
1.6
V
Logic Input Low
2.6 V < V
IN
< 5.5 V
0.6
V
Logic Input Current
V
IN
= 5.5V
0.1
1
A
MAX1958/MAX1959
W-CDMA/N-CDMA Cellular Phone HBT PA
Management ICs
4
_______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (OP AMP)
(V
INP
= V
IN
= V
VCC
= V
SHDN2
= 2.7V, V
AOUT
= V
VCC
/2, R
L
=
connected from AOUT to V
VCC
/2, V
PGND
= V
AGND
= V
SHDN1
=
V
SHDN3
= V
PWM
= V
ADJ
= 0, OUT = LX = TOUT = REF = COMP = unconnected, V
CM
= 0, T
A
= 0C to +85C, unless otherwise
noted. Typical values are at T
A
= +25C.)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Supply Voltage Range
2.6
5.5
V
V
VCC
= 2.6V
320
800
V
VCC
= 5V
375
900
Supply Current
V
SHDN2
= 0, V
VCC
= 5.5V
0.1
2.0
A
Input Offset Voltage
V
AGND
- 0.1V
V
CM
V
VCC
+ 0.1V
0.4
3.0
mV
Input Bias Current
V
AGND
- 0.1V
V
CM
V
VCC
+ 0.1V
10
100
nA
Input Offset Current
V
AGND
- 0.1V
V
CM
V
VCC
+ 0.1V
1
10
nA
Input Resistance
V
IN-
- V
IN+
10mV
4
M
Input Common-Mode Voltage
Range, V
CM
-0.1
V
VCC
+
0.1
V
Common-Mode Rejection Ratio,
CMRR
V
AGND
- 0.1V
V
CM
V
VCC
+ 0.1V
60
80
dB
Power-Supply Rejection Ratio,
PSRR
2.6V < V
VCC
< 5.5V
70
90
dB
V
AGND
+ 0.05V
V
AOUT
V
VCC
- 0.05V
R
L
= 100k
120
Large-Signal Voltage Gain, AVOL
V
AGND
+ 0.20V
V
AOUT
V
VCC
- 0.20V
R
L
= 2k
85
110
dB
R
L
= 100k
1
Output Voltage Swing High, VOH
V
VCC
-V
VOH
R
L
= 2k
35
90
mV
R
L
= 100k
1
Output Voltage Swing Low, VOL
V
VOL
- V
AGND
RL = 2k
30
90
mV
Sourcing, V
VCC
= 5V
11
Output Short-Circuit Current
Sinking, V
VCC
= 5V
30
mA
SHDN2 Logic Low
2.6V < V
VCC
< 5.5V
0.3 x
V
VCC
V
SHDN2 Logic High
2.6V < V
VCC
< 5.5V
0.7 x
V
VCC
V
SHDN2 Input Current
0 < V
SHDN2
< V
VCC
0.5
120
nA
Gain Bandwidth Product, GBW
1
MHz
Phase Margin,
M
70
Degrees
Gain Margin, GM
20
dB
Slew Rate, SR
0.4
V/s
Input Voltage Noise Density
f = 10kHz
52
nV/
Hz
Input Current Noise Density
f = 10kHz
0.1
pA/
Hz
Capacitive-Load Stability
AVCL
= 1V/V (Note 2)
470
pF
Shutdown Delay Time
3
s
Enable Delay Time
4
s
MAX1958/MAX1959
W-CDMA/N-CDMA Cellular Phone HBT PA
Management ICs
_______________________________________________________________________________________
5
ELECTRICAL CHARACTERISTICS (OP AMP) (continued)
(V
INP
= V
IN
= V
VCC
= V
SHDN2
= 2.7V, V
AOUT
= V
VCC
/2, R
L
=
connected from AOUT to V
VCC
/2, V
PGND
= V
AGND
= V
SHDN1
=
V
SHDN3
= V
PWM
= V
ADJ
= 0, OUT = LX = TOUT = REF = COMP = unconnected, V
CM
= 0, T
A
= 0C to +85C, unless otherwise
noted. Typical values are at T
A
= +25C.)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Power-On Time
4
s
Input Capacitance
2.5
pF
Total Harmonic Distortion
f =10kHz, V
AOUT
= 2V
P-P
, AVCL
=1, V
VCC
= 5V,
R
AOUT
= 100k
to V
VCC
/2
0.01
%
Settling Time to 0.01%
V
AOUT
= 4V step, V
VCC
= 5V, AVCL
= 1
10
s
Active Discharge Output
Impedance
V
SHDN2
= 0, I
AOUT
= 1mA
100
500
ELECTRICAL CHARACTERISTICS (TEMPERATURE SENSOR)
(V
INP
= V
IN
= V
VCC
= V
SHDN3
= 2.7V, V
AGND
= V
PGND
= V
PWM
= V
SHDN1
= V
SHDN2
= V
ADJ
= 0, IN- = IN+ = AOUT = COMP = LX =
OUT = REF = unconnected, C
TOUT
= 0.01F (min), T
A
= 0C to +85C, unless otherwise noted. Typical values are at T
A
= +25C.)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
T
A
= 0
C (Note 2)
-3.5
+3.5
T
A
= +25
C (Note 2)
-2.5
+2.5
Temperature Sensor Error
(Note 3)
T
A
= +85
C
-2.5
+2.5
C
Output Voltage at +27
C
1.56
V
Sensor Gain (Note 4)
-11.64
mV/
C
Nonlinearity
0.4
%
Load Regulation
0
I
LOAD
15A
-5
mV
Line Regulation
2.6V
V
VCC
5.5V
-2.3
mV/V
Quiescent Current
2.6V
V
VCC
5.5V
10
18
A
SHDN3 Logic High Voltage
2.6V < V
VCC
< 5.5V
1.6
V
SHDN3 Logic Low Voltage
2.6V < V
VCC
< 5.5V
0.6
V
SHDN3 Current
V
VCC
= 5.5V
0.1
1.0
A
PDF 
ZIP