MAXIM MAX1727EUG

19-1489; Rev 0; 12/00
GSM Cellular/PCN Handset RF Power
Management IC
The MAX1727 is a radio frequency (RF) power-management IC intended for Global Satellite Mobile (GSM)
communication cellular and personal cellular network
(PCN) handsets using a single lithium-ion (Li+) cell battery with inputs from +3.1V to +5.5V. The IC contains
four low-noise, low-dropout (LDO) linear regulators to
provide all the supply voltage requirements for the RF
portion of the handset, and two high-speed, wide-bandwidth op amps for the power amplifier (PA) power control loop.
Each LDO has its own individual on/off control to maximize design flexibility. All LDOs are internally trimmed
to a fixed output voltage and are optimized for low
noise and high crosstalk isolation. LDO1 (R1OUT) is
rated for 100µA and is optimized for lowest quiescent
current. It is intended to power the transmitter, receiver,
and synthesizer. LDO2 (R2OUT) is rated for 50mA. It is
intended to power the TCXO, GSM, and PCN highpower voltage-controlled oscillators (VCOs). LDO3
(R3OUT) is rated for 20mA and is optimized to suppress line transients. It is intended to power the UHF
offset VCO. LDO3 has an auxiliary 2.5Ω switched output to allow the VCO to be powered up with precise
timing. LDO4 (R3BYP) is rated for 20mA. It is intended
to power this IC’s reference and LDO3 for superior line
rejection. LDO4 and the reference will be powered on if
any of the R1EN, R2EN, and R3EN enable inputs are
logic high.
The op amps have wide bandwidth, high DC accuracy,
high slew rate, and Rail-to-Rail® inputs and outputs.
The op amps can sink and source 3mA, and include
two 2.5Ω switched outputs. The op amps and switched
outputs may be used independently or may be configured to provide optimized power for a PA control loop.
Applications
GSM Cellular or PCN Handsets
Single-Cell Li+ Systems
3-Cell NiMH, NiCD, or Alkaline Systems
Typical Application Circuit and Functional Diagram appear
at end of data sheet.
Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd.
Features
♦ +3.1V to +5.5V Input Range
♦ One 2.90V, 100mA Low IQ LDO
♦ One 2.75V, 50mA Low IQ LDO
♦ One 2.75V, 20mA Low IQ LDO
♦ Low-Noise LDOs
<90µVRMS from 10Hz to 100kHz
>80dB Crosstalk Isolation at 10kHz
>70dB PSRR at 1kHz
♦ ±5% Accuracy Over Line, Load, and Temperature
♦ Three 2.5Ω Switched Outputs
♦ Current and Thermal Limit
♦ Two Undedicated Op Amps
Rail-to-Rail CMR Inputs and Outputs
>120dB Channel Separation
>85dB PSRR at 1kHz
♦ 10µA (max) Shutdown Current
Ordering Information
PART
TEMP. RANGE
PIN-PACKAGE
MAX1727EUG
-40°C to +85°C
24 TSSOP
Pin Configuration
R3EN 1
24 GND
PCEN 2
23 CBYP
PC1+ 3
22 ENVCO
PC1- 4
21 VCOOUT
PC1OUT 5
VPC 6
20 R3OUT
MAX1727
PC2OUT 7
19 R3BYP
18 R1OUT
PC2- 8
17 VCC
PC2+ 9
16 R2OUT
PCNAPC 10
15 R2EN
BANDSWIN 11
14 R1EN
GSMAPC 12
13 GSM/PCN
TSSOP
________________________________________________________________ Maxim Integrated Products
1
For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
MAX1727
General Description
MAX1727
GSM Cellular/PCN Handset RF Power
Management IC
ABSOLUTE MAXIMUM RATINGS
VCC, VPC to GND......................................................-0.3V to +7V
PC1-, PC1+, PC2-, PC2+ to GND ............................-0.3V to +7V
GSM/PCN, BANDSWIN to GND ...............................-0.3V to +7V
PC1OUT, PC2OUT to GND ......................................-0.3V to +7V
R1OUT, R2OUT, R3BYP to GND................-0.3V to (VCC + 0.3V)
R3OUT, CBYP to GND ..........................-0.3V to (VR3BYP + 0.3V)
R1EN, R2EN, R3EN, ENVCO,
PCEN to GND ..........................................-0.3V to (VCC + 0.3V)
VCOOUT to GND ..................................-0.3V to (VR3OUT + 0.3V)
GSMAPC, PCNAPC to GND ...........-0.3V to (VBANDSWIN + 0.3V)
Continuous Power Dissipation (TA = +70°C)
24-Pin TSSOP (derate 12.2mW/°C above +70°C) ......975mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature(soldering, 10s) ..................................+300°C
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.
ELECTRICAL CHARACTERISTICS
(VCC = +3.1V to +5.5V, VPC = +2.8V to +5.5V, GND = 0, CBYP = 0.01µF, TA = 0°C to +85°C, unless otherwise noted. Typical values
are at TA = +25°C.)
MAX
UNITS
VCC Operating Voltage
PARAMETER
CONDITIONS
3.1
5.5
V
VPC Operating Voltage
2.8
5.5
V
2.62
V
UVLO Falling
VCC falling
UVLO Rising
VCC rising
MIN
2.3
TYP
2.4
2.5
V
SUPPLY CURRENT
Supply Current in Shutdown
All regulators and op amps off, VCC = +3.6V
0.01
10
µA
VCC + VPC Supply Current
All regulators and op amps on, VCC = VPC
1.80
3.0
mA
1.250
1.275
V
0.2
5
mV
2.90
3.00
V
REFERENCE
Reference Bypass Output
ICBYP = 0, do not draw current from this pin
REF Supply Rejection
+3.1V ≤ VCC ≤ +5.5V
1.225
REGULATOR R1
R1OUT Output Voltage
Dropout Voltage
0.1mA ≤ IR1OUT ≤ 100mA
2.80
IR1OUT = 1mA
1
IR1OUT = 100mA
Load Regulation
0.1mA ≤ IR1OUT ≤ 100mA
Line Regulation
+3.1V ≤ VCC ≤ +5.5V, IR1OUT = 10mA
R1OUT Leakage Current
R1EN, R1OUT = 0, VCC = +5.5V
100
225
mV
8
45
mV
0.5
10
mV
2
µA
REGULATOR R2
R2OUT Output Voltage
Dropout Voltage
0.1mA ≤ IR2OUT ≤ 50mA
2.61
2.75
2.90
V
IR2OUT = 1mA
1
IR2OUT = 50mA
100
225
8
45
mV
0.5
10
mV
2
µA
2.90
V
Load Regulation
0.1mA ≤ IR2OUT ≤ 50mA
Line Regulation
+3.1V ≤ VCC ≤ +5.5V, IR2OUT = 10mA
R2OUT Leakage Current
R2EN, R2OUT = 0, VCC = +5.5V
mV
REGULATOR R3
R3OUT Output Voltage
Dropout Voltage
2
0.1mA ≤ IR3OUT ≤ 20mA
2.61
2.75
IR3OUT = 1mA
1
IR3OUT = 20mA
45
_______________________________________________________________________________________
100
mV
GSM Cellular/PCN Handset RF Power
Management IC
(VCC = +3.1V to +5.5V, VPC = +2.8V to +5.5V, GND = 0, CBYP = 0.01µF, TA = 0°C to +85°C, unless otherwise noted. Typical values
are at TA = +25°C.)
PARAMETER
CONDITIONS
Load Regulation
0.1mA ≤ IR3OUT ≤ 20mA
Line Regulation
+3.1V ≤ VCC ≤ +5.5V, IR3OUT = 10mA
R3OUT Leakage Current
R3EN, R3OUT = 0, VCC = +5.5V
MIN
TYP
MAX
UNITS
5
45
mV
0.2
10
mV
2
µA
2.4
5.1
Ω
2.95
3.05
V
VCOOUT SWITCH (R3 SWITCH)
On-Resistance
REGULATOR R4 (R3BYP)
R3BYP Output Voltage
Dropout Voltage
0.1mA ≤ IR3BYP ≤ 20mA
2.85
IR3BYP = 1mA
1
IR3BYP = 20mA
45
100
mV
Load Regulation
0.1mA ≤ IR3BYP ≤ 20mA
10
45
mV
Line Regulation
+3.1V ≤ VCC ≤ +5.5V, IR3BYP = 10mA
0.7
10
mV
R3BYP Leakage Current
R1EN, R2EN, R3EN = 0, R3BYP = 0, VCC = +5.5V
2
µA
2
mV
150
nA
5
µA
30
nA
VPC 0.3
V
PA CONTROL OP AMPS (PC1, PC2)
Input Offset Voltage
Input Bias Current
VCM = +0.3V to (VPC - 0.3V)
Input Bias Current
Shutdown Mode
VCM = 0 to VCC,
VPC = 0, PCEN = GND
Input Offset Current
Input Common-Mode Range
Gain-Bandwidth Product
0.3
RLOAD = 1kΩ connected to VPC/2, CLOAD = 100pF to
GND
4
MHz
1
V/µs
10Hz ≤ f ≤ 1kHz
85
dB
Slew Rate
PSRR
CMRR
10Hz ≤ f ≤ 1kHz
Output Voltage Swing
ILOAD = ±3 mA
80
0.2
dB
2.62
V
BAND SWITCH (GSMAPC, PCNAPC)
On-Resistance GSMAPC
0.3V < VGSMAPC < VPC - 0.3V, ILOAD = ±3 mA
2.2
5
Ω
On-Resistance PCNAPC
0.3V < VPCNAPC < VPC - 0.3V, ILOAD = ±3 mA
2.2
5
Ω
0.4
V
1
µA
LOGIC AND CONTROL INPUTS (R1EN, R2EN, R3EN, ENVCO, GSM/PCN, PCEN)
Input Low Level
Input High Level
Logic Input Current
2.0
V
0 < VIN < +5.5V
THERMAL SHUTDOWN (R3 SWITCH)
Threshold Rising
Hysteresis
IOUT = 1mA
150
°C
20
°C
_______________________________________________________________________________________
3
MAX1727
ELECTRICAL CHARACTERISTICS (continued)
MAX1727
GSM Cellular/PCN Handset RF Power
Management IC
ELECTRICAL CHARACTERISTICS
(VCC = +3.1V to +5.5V, VPC = +2.8V to +5.5V, GND = 0, CBYP = 0.01µF, TA = -40°C to +85°C, unless otherwise noted.) (Note 1)
MIN
MAX
VCC Operating Voltage
PARAMETER
CONDITIONS
3.1
5.5
V
VPC Operating Voltage
2.8
5.5
V
2.62
V
UVLO Falling
VCC falling
UVLO Rising
VCC rising
2.3
UNITS
V
SUPPLY CURRENT
Supply Current in Shutdown
All regulators and op amps off, VCC = +3.6V
10
µA
VCC Supply Current
All regulators and op amps on
3.0
mA
1.281
V
5
mV
3.00
V
mV
REFERENCE
Reference Bypass Output
ICBYP = 0, do not draw current from this pin
REF Supply Rejection
+3.1V ≤ VCC ≤ +5.5V
1.219
REGULATOR R1
R1OUT Output Voltage
0.1mA ≤ IR1OUT ≤ 100mA
2.80
Dropout Voltage
IR1OUT = 100mA
225
Load Regulation
0.1mA ≤ IR1OUT ≤ 100mA
45
mV
Line Regulation
+3.1V ≤ VCC ≤ +5.5V, IR1OUT = 10mA
10
mV
R1OUT Leakage Current
R1EN, R1OUT = 0, VCC = +5.5V
2
µA
2.90
V
mV
REGULATOR R2
R2OUT Output Voltage
0.1mA ≤ IR2OUT ≤ 50mA
2.61
Dropout Voltage
IR2OUT = 50mA
225
Load Regulation
0.1mA ≤ IR2OUT ≤ 50mA
45
mV
Line Regulation
+3.1V ≤ VCC ≤ +5.5V, IR2OUT = 10mA
10
mV
R2OUT Leakage Current
R2EN, R2OUT = 0, VCC = +5.5V
2
µA
2.90
V
mV
REGULATOR R3
R3OUT Output Voltage
0.1mA ≤ IR3OUT ≤ 20mA
2.61
Dropout Voltage
IR3OUT = 20mA
100
Load Regulation
0.1mA ≤ IR3OUT ≤ 20mA
45
mV
Line Regulation
+3.1V ≤ VCC ≤ +5.5V, IR3OUT = 10mA
10
mV
R3OUT Leakage Current
R3EN, R3OUT = 0, VCC = +5.5V
2
µA
5.1
Ω
VCOOUT SWITCH (R3 SWITCH)
On-Resistance
REGULATOR R4 (R3BYP)
4
R3BYP Output Voltage
0.1mA ≤ IR3BYP ≤ 20mA
3.05
V
Dropout Voltage
IR3BYP = 20mA
100
mV
Load Regulation
0.1mA ≤ IR3BYP ≤ 20mA
45
mV
Line Regulation
+3.1V ≤ VCC ≤ +5.5V, IR3BYP = 10mA
10
mV
R3BYP Leakage Current
R1EN, R2EN, R3EN = 0, R3BYP = 0, VCC = +5.5V
2
µA
2.85
_______________________________________________________________________________________
GSM Cellular/PCN Handset RF Power
Management IC
(VCC = +3.1V to +5.5V, VPC = +2.8V to +5.5V, GND = 0, CBYP = 0.01µF, TA = -40°C to +85°C, unless otherwise noted.) (Note 1)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
PA CONTROL OP AMPS (PC1, PC2)
Input Offset Voltage
2
Input Bias Current
VCM = 0.3V to (VPC - 0.3V)
Input Bias Current
Shutdown Mode
VCM = 0 to VCC,
VPC = 0, PCEN = GND
150
nA
5
µA
Input Offset Current
Input Common-Mode Range
ILOAD = ±3 mA
Output Voltage Swing
30
nA
0.3
VPC
- 0.3
V
0.2
2.62
V
BAND SWITCH (GSMAPC, PCNAPC)
On-Resistance GSMAPC
0.3V < VGSMAPC < VPC- 0.3V, ILOAD = ±3 mA
5
Ω
On-Resistance PCNAPC
0.3V < VPCNAPC < VPC- 0.3V, ILOAD = ±3 mA
5
Ω
0.4
V
1
µA
LOGIC AND CONTROL INPUTS (R1EN, R2EN, R3EN, ENVCO, GSM/PCN, PCEN)
Input Low Level
Input High Level
2.0
Logic Input Current
V
0 < VIN < +5.5V
Note 1: Specifications to -40°C are guaranteed by design, not production tested.
Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
NO LOAD*
0.6
0.4
LDO3
1.125
1.120
1.115
LDO2
1.110
*ALL REGULATORS ON
0
0
1
2
3
4
SUPPLY VOLTAGE (V)
5
LDO1
2.85
2.80
LDO3
2.75
LDO2
2.70
1.105
0.2
2.90
OUTPUT VOLTAGE (V)
1.0
LDO1
MAX1727 toc03
1.130
GROUND CURRENT (mA)
1.2
2.95
MAX1727 toc02
FULL LOAD*
GROUND CURRENT (mA)
1.135
MAX1727 toc01
1.4
0.8
OUTPUT VOLTAGE
vs. SUPPLY VOLTAGE
GROUND CURRENT
vs. LOAD CURRENT
GROUND CURRENT
vs. SUPPLY VOLTAGE
VCC = +3.6V
1.100
0
20
40
60
LOAD CURRENT (mA)
80
100
2.65
2.7
3.2
3.7
4.2
4.7
5.2
SUPPLY VOLTAGE (V)
_______________________________________________________________________________________
5
MAX1727
ELECTRICAL CHARACTERISTICS (continued)
Typical Operating Characteristics (continued)
(TA = +25°C, unless otherwise noted.)
2.84
2.82
2.80
LDO2
2.76
2.74
VCC = +3.6V
20
40
60
80
30
20
20
10
10
VCC = +3.6V
0
0
20
40
60
1
100
10
100
1k
10k
100k
GAIN AND PHASE vs. FREQUENCY
(RL = 1kΩ, CL = 100pF)
INPUT OFFSET VOLTAGE
vs. TEMPERATURE
60
40
0
PHASE
1M
10
40
30
20
MAX1727 toc09
0
-100
-200
-40
-15
10
35
60
LINE-TRANSIENT RESPONSE
REGULATOR 1
MAX1727 toc12
MAX1727 toc11
4.0
4.0V
VIN
3.6V
3.5
VCC = +2.8V
3.0
2.5
2.0
1.5
VOUT
1.0
10
VCC = +5.5V
800
300
100
50
-10
-100
-350
-600
0.5
OFFSET VOLTAGE (µV)
85
TEMPERATURE (°C)
4.5
ON-RESISTANCE (Ω)
193 UNITS
VCM = 0.3V
TA = +25°C
100
10M
5.0
MAX1727 toc10
100k
200
-500
1M
BAND SWITCH ON-RESISTANCE
vs. BANDSWIN VOLTAGE
10k
100
1k
INPUT OFFSET VOLTAGE DISTRIBUTION
1k
300
-400
FREQUENCY (Hz)
100
400
-300
10k 100k
FREQUENCY (Hz)
10
500
MAX1727 toc08
GAIN
1M
20mV/div
AC-COUPLED
LDO1 TO LDO3
80
60
40
20
0
-20
-40
-60
-80
-100
-120
-140
-160
-180
OFFSET VOLTAGE (µV)
80
GAIN (dB)/PHASE (DEGREES)
REGULATOR ISOLATION vs. FREQUENCY
(RL = 300Ω)
20
6
80
FREQUENCY (Hz)
100
0
40
30
0
MAX1727 toc07
REGULATOR ISOLATION (dB)
LDO1
40
LDO2
50
LOAD CURRENT (mA)
LDO1 TO LDO2
50
50
LDO1
60
LOAD CURRENT (mA)
120
60
80
70
60
100
LDO3
90
LDO3
70
MAX1727 toc06
80
2.72
0
LDO2
PSRR (dB)
2.86
LDO3
90
DROPOUT VOLTAGE (mV)
OUTPUT VOLTAGE (V)
LDO1
100
MAX1727 toc05
2.90
2.78
100
MAX1727 toc04
2.92
2.88
REGULATOR PSRR vs. FREQUENCY
(RLOAD = 300Ω)
DROPOUT VOLTAGE
vs. LOAD CURRENT
DROPOUT VOLTAGE
vs. LOAD CURRENT
NUMBER OF UNITS
MAX1727
GSM Cellular/PCN Handset RF Power
Management IC
ILOAD = 10mA
0
0
1
2
3
4
5
6
40µs/div
BANDSWIN VOLTAGE (V)
_______________________________________________________________________________________
GSM Cellular/PCN Handset RF Power
Management IC
LOAD-TRANSIENT RESPONSE
REGULATOR 1
LINE-TRANSIENT RESPONSE
REGULATOR 2
MAX1727 toc13
MAX1727 toc14
100mA
IOUT
LOAD-TRANSIENT RESPONSE
REGULATOR 2
VIN
MAX1727 toc15
4.0V
10mA
3.6V
50mA
VOUT
5mA
50mV/div
AC-COUPLED
VOUT
20mV/div
AC-COUPLED
50mV/div
AC-COUPLED
IOUT
VOUT
ILOAD = 10mA
40µs/div
ILOAD = 10mA
40µs/div
40µs/div
LINE-TRANSIENT RESPONSE
REGULATOR 3
LOAD-TRANSIENT RESPONSE
REGULATOR 3
MAX1727 toc16
MAX1727 toc17
4.0V
VIN
10mA
3.6V
IOUT
VOUT
50mV/div
AC-COUPLED
20mV/div
AC-COUPLED
0.1mA
VOUT
ILOAD = 10mA
40µs/div
40µs/div
OP AMP LARGE-SIGNAL
TRANSIENT RESPONSE
OP AMP SMALL-SIGNAL
TRANSIENT RESPONSE
MAX1727 toc18
MAX1727 toc19
5V
OUT
200mV
IN
0
0
5V
IN
200mV
OUT
AV = +1V/V
RL = 1kΩ
20µs/div
0
AV = +1V/V
RL = 1kΩ
0
1µs/div
_______________________________________________________________________________________
7
MAX1727
Typical Operating Characteristics (continued)
(TA = +25°C, unless otherwise noted.)
GSM Cellular/PCN Handset RF Power
Management IC
MAX1727
Pin Description
PIN
NAME
1
R3EN
2
PCEN
Op Amp and Band Switch Mux Enable Input
3
PC1+
Op Amp 1 Noninverting Input
4
PC1-
5
PC1OUT
6
VPC
7
PC2OUT
8
PC2-
9
PC2+
10
PCNAPC
11
BANDSWIN
Op Amp 1 Inverting Input
Op Amp 1 Output
Op Amp Power Supply
Op Amp 2 Output
Op Amp 2 Inverting Input
Op Amp 2 Noninverting Input
Band Switch PCN Output. Normally connected to PCN PA APC. Internally shorts to ground when
not selected.
Band Switch Input. Normally connected to PC2OUT.
12
GSMAPC
Band Switch GSM Output. Normally connected to GSM PA APC. Internally shorts to ground when
not selected.
13
GSM/PCN
Band Switch Control Input. With logic high, BANDSWIN is connected to GSMAPC. With logic low,
BANDSWIN is connected to PCNAPC.
14
R1EN
Regulator R1 Enable Input
15
R2EN
Regulator R2 Enable Input
16
R2OUT
17
VCC
18
R1OUT
Output of Linear Regulator 1. 100mA output current. Use 1µF low ESR bypass capacitor to GND.
R3BYP
Output of Linear Regulator 4. Power supply for regulator R3 and 1.25V reference. Use 1µF low ESR
bypass capacitor to GND.
19
8
FUNCTION
Regulator R3 Enable Input
Output of Linear Regulator 2. 50mA output current. Use 1µF low ESR bypass capacitor to GND.
Regulator Power Supply
20
R3OUT
21
VCOOUT
Output of Linear Regulator 3. 20mA output current. Use 1µF low ESR bypass capacitor to GND.
22
ENVCO
23
CBYP
1.25V Voltage Reference Bypass Pin. Connect low-leakage, 0.01µF bypass capacitor to GND to
minimize noise at the output.
24
GND
Ground
Switched R3 Output
VCO Switch Control Input. With logic high, VCOOUT is connected to R3OUT. With logic low,
VCOOUT is high impedance.
_______________________________________________________________________________________
GSM Cellular/PCN Handset RF Power
Management IC
The MAX1727 is an ideal RF power management IC for
the GSM cellular phone. The MAX1727 contains four
LDOs, three switches, and two high-speed, high-bandwidth op amps. The LDOs power transmitter, receiver,
synthesizer, TCXO, and VCOs. The switches are used
to optimize power consumption and to sequence power
properly. The op amps provide essential loop control
for the PA. The MAX1727 contains all the building
blocks necessary to design a high-performance RF circuit (see Typical Application Circuit).
The MAX1727 has an input voltage range of +3.1V to
+5.5V, perfect for single-cell Li+ cell or 3-cell NiMH battery applications. If any one of LDO1 through LDO3 is
enabled, LDO4 and the internal 1.25V reference are
powered on. Once LDO4 and the reference voltage
reach regulation, the commanded LDOs are powered
on. All three LDOs (LDO1, LDO2, LDO3) must be disabled to shut down the internal reference. LDO4 is
used as a preregulator to provide extremely high PSRR
of 90dB at 1kHz for LDO3. The output current capability
of LDO3 and LDO4 is limited to 20mA. LDO4 output
can be loaded as long as total current demand by
LDO4 load and LDO3 load is less than 20mA.
Clear transmission and reception can only be achieved
with a low-noise power supply. All the LDOs of the
MAX1727 are designed with <90µV RMS noise from
10Hz to 100kHz, and each LDO achieves >70dB
PSRR.
The band switches of the MAX1727 are both grounded
when PCEN is in logic low state. When PCEN is in logic
high state, GSM/PCN determines the switch positions.
If GSM/PCN is low, PCNAPC is engaged. If GSM/PCN
is high, GSMAPC output is engaged.
All the regulators feature high PSRR and excellent load
and line regulation characteristics and are designed for
single Li+ battery applications where a pulsed current
demand is required from the battery. For a load requiring significant isolation from transients on the input,
REG3 should be used with REG4 configured as a preregulator to provide improved rejection.
The minimum I/O voltage differential (dropout voltage)
determines the lowest usable supply voltage. Once
dropout has been reached, the series pass transistor is
fully on, and regulation ceases. The output will track the
input voltage as the input voltage is further lowered. For
a P-channel series pass element (as used here), dropout voltage is a function of drain-to-source on-resistance multiplied by the load current.
Each regulator features a P-channel MOSFET series
pass transistor sized to deliver the rated output current
for each regulator. A P-channel MOSFET requires
almost no drive current to the gate. This significantly
reduces the quiescent current compared to bipolar
PNP series pass transistor regulators, particularly in
dropout when the DC current gain of the PNP transistor
is reduced to nearly unity. A MOSFET design retains its
low quiescent current even in dropout, with and without
load.
Reference Bypass
An external bypass capacitor is connected to CBYP to
reduce the inherent reference noise. The capacitor
forms a lowpass filter in conjunction with an internal
network. Use a 0.01µF nonpolarized capacitor connected as close to the CBYP pin as possible. For lowest
noise, increase the bypass capacitor to 0.1µF. Values
above 100nF provide no performance improvement
and are therefore not recommended. Do not place any
additional loading on this pin.
Linear Regulators
Regulators 1–4 are low-noise, low-dropout, low-quiescent-current linear regulators. Each regulator consists
of an error amplifier, internal feedback voltage-divider,
and P-channel MOSFET pass transistor. All regulators
share a 1.25V reference. The reference is connected to
the inverting input of each of the regulator’s error amplifiers. The error amplifiers compare the reference with
the feedback voltage from each of the regulator outputs
and amplify the difference. If the feedback voltage is
lower than the reference voltage, the pass transistor
gate is pulled lower, which allows more current to pass
into the output load to increase the output voltage. If
the feedback voltage is too high, the pass transistor
gate is pulled up, allowing less current into the load.
The feedback is provided by an internal, trimmed resistor-divider connected at each of the regulator outputs.
Regulator Short-Circuit Protection
Each regulator has a separate current-limit circuit within
the overall feedback loop. The typical values for current
limit are: REG1 = 250mA; REG2/REG3/REG4 = 125mA.
Each regulator will survive a continuous short circuit at
the output, until the IC thermal limit control powers
down all the regulators.
Thermal Overload Protection
Thermal overload protection limits the total power dissipation by measuring the die temperature. When
+150°C is reached, the thermal sensor signals the shutdown logic for all the regulators. Once the die temperature cools by 20°C, the regulators will restart. If the
overload persists, the regulators will cycle on and off as
the die temperature fluctuates.
_______________________________________________________________________________________
9
MAX1727
Detailed Description
MAX1727
GSM Cellular/PCN Handset RF Power
Management IC
Capacitor Selection and Regulator Stability
Minimum recommended output capacitance for all the
regulators is 1µF with a maximum ESR of 0.4Ω. For
lower noise requirements, use a 10µF capacitor on
each regulator.
Note that some ceramic dielectrics exhibit large capacitance and ESR variation with temperature. Z5U and
Y5V dielectrics may require a minimum value of 2.2µF
nominal output capacitance, especially a low temperature operation.
Op Amps
Two uncommitted unity-gain-stable op amps are available for use in the MAX1727. Gain bandwidth is typically 4MHz and slew rate 1V/µs. Gain and phase margins
are typically 8dB and 63° when loaded with 1kΩ and
100pF at the output. The input stages are differential
CMOS transistors providing an input common-mode
range extending to 300mV within the positive supply
rail (VPC) and ground. Input offset voltage is 2mV
(max), with bias current of 150nA (max).
A separate supply input is provided for the two op
amps, allowing them to be powered by supplies different from REG1–REG4. The amplifier’s excellent PSRR
to beyond 1kHz allows the supply to be connected
directly to the battery. Decouple the supply pin (VPC)
with a 0.1µF ceramic capacitor in parallel with at least
1µF. Place the 0.1µF as close to the supply pin as possible. Both op amps have a common logic-controlled
shutdown pin, allowing the inputs to remain connected
to a supply while reducing quiescent current to a very
low level. The op amp supply current is reduced to 5µA
during shutdown mode.
The output stages are all CMOS, allowing rail-to-rail
swing at the output (load dependent). For a ±3mA load,
the output will swing to within 200mV of either the positive supply (VPC) or ground. If an op amp is unused, the
positive input should be connected to ground, and the
output should be connected back to the negative input.
Connecting an unused op amp as a grounded unitygain buffer prevents oscillation and saturation, which
causes inconsistent supply-current consumption.
power supply. The logic-controlled changeover is
gated by the op amp enable line (PCEN).
Figure 1 shows a single op amp within the MAX1727
used in a dual PA APC loop. The RF envelope at the
active PA output is sampled by the 20dB coupler and
detected by the temperature-compensated dual
Schottky diode pair. The baseband DAC ramp control
is summed with the averaged detected envelope by an
inverting integrator stage to produce an APC signal.
This is connected to the operational PA by the SPDT
switch. The unused PA APC line is grounded. This prevents the unused PA from accidentally powering up.
Also, a grounded APC line keeps the PA in a low-quiescent-current standby mode.
Figure 2 shows an alternative method of PA control
where the average DC supply current to the active PA
is used as a measure of the average RF power into the
load (antenna). The circuit takes advantage of the railto-rail performance and CMRR of the op amps. The PA
average DC current is sampled by the sense resistor
and amplified differentially before summation into the
second integrating stage with the baseband ramp DAC
signal. As shown in Figure 1, the APC signal is routed
through the SPDT switches to the active PA.
Chip Information
TRANSISTOR COUNT: 1324
Power Switches
The MAX1727 contains three 2.5Ω CMOS switches.
One is connected to the REG3 output and is suitable
for fast enabling of a load. The other two switches are
wired as SPDT switches and are used to route the APC
outputs from a loop amplifier. When not required, the
APC control is grounded. This prevents spurious
power-up of the unused PA and eliminates a low onresistance, high-current switch in series with the PA
10
______________________________________________________________________________________
GSM Cellular/PCN Handset RF Power
Management IC
MAX1727
VRF
VPC
PC1+
PC1OUT
OP1
PC1PC2OUT
PC2PA
CONTROL
RAMP
FROM BB
CONTROL
DAC
OP2
PCEN
PC2+
MAX1727
GSM PA
BANDSWIN
GSMAPC
20dB
COUPLER
GSM/PCN
PCN PA
PCNAPC
GND
Figure 1. Single Op Amp PA Automatic Power Control Loop
______________________________________________________________________________________
11
MAX1727
GSM Cellular/PCN Handset RF Power
Management IC
FROM
BATTERY
VPC
RSENSE
PC1+
PC1OUT
OP1
PC1PC2OUT
DC
SUPPLY
TO
PA
PC2PA
CONTROL
RAMP
FROM BB
CONTROL
DAC
OP2
PC2+
PCEN
MAX1727
GSM PA
BANDSWIN
GSMAPC
20dB
COUPLER
PCN PA
GSM/PCN
PCNAPC
GND
Figure 2. High-Side Average Current-Sense PA Control
12
______________________________________________________________________________________
GSM Cellular/PCN Handset RF Power
Management IC
+3.1V
TO
+5.5V
VCC
R1OUT
2.90V
100mA
REG1
Li+
BATTERY
1µF
R1EN
R2OUT
REG2
2.75V
50mA
1µF
R2EN
R3OUT
REG3
2.75V
20mA
1µF
R3EN
ENVCO
VCOOUT
2.95V
20mA
R3BYP
1µF
CBYP
REF
REG4
0.01µF
+2.8V
TO
+5.5V
VPC
MAX1727
PC1+
PC1OUT
OP1
PC1-
PC2+
PC2OUT
OP2
PC2PCEN
BANDSWIN
GSMAPC
PCNAPC
GSM/PCN
GND
______________________________________________________________________________________
13
MAX1727
Typical Application Circuit
MAX1727
GSM Cellular/PCN Handset RF Power
Management IC
Functional Diagram
+3.1V
TO
+5.5V
R1OUT
VCC
R2OUT
R1EN
MAX1727
R2EN
LOW-DROPOUT
LINEAR
REGULATORS
R3EN
R3OUT
R3BYP
2.90V
100mA
2.75V
50mA
2.75V
20mA
2.95V
20mA
PC1+
PC1OUT
OP1
PC1-
PC2+
PC2OUT
OP2
PC2BANDSWIN
GSMAPC
PCNAPC
GND
14
______________________________________________________________________________________
GSM Cellular/PCN Handset RF Power
Management IC
TSSOP,NO PADS.EPS
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
15 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2000 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
MAX1727
Package Information