MAX8500 MAXIM [Maxim Integrated Products], MAX8500 Datasheet

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MAX8500

Manufacturer Part Number
MAX8500
Description
PWM Buck Converters with Bypass FET for N-CDMA/W-CDMA Handsets
Manufacturer
MAXIM [Maxim Integrated Products]
Datasheet
The MAX8500–MAX8504 PWM DC-to-DC buck converters
are optimized with integrated bypass FET (0.25
to provide power to the PA in N-CDMA and W-CDMA
cell phones. The devices have a low on-resistance FET
to bypass the external inductor for low dropout of only
150mV at 600mA load, regardless of inductor series
resistance. The supply voltage range is from 2.6V to
5.5V and the guaranteed converter output current is
600mA. The 1MHz PWM switching frequency allows for
small external components.
The MAX8500–MAX8503 are dynamically controlled to
provide varying output voltages from 0.4V to V
The LDO regulation point is slightly lower than the PWM
converter such that the transition into and out of dropout
is smooth, regardless of the inductor resistance. The
MAX8504 is programmed for fixed 1.25V to 2.5V output
with external resistors. It features a high-power bypass
mode that connects the output directly to the battery. All
devices are designed to achieve an output settling time
of less than 30µs for a full-scale change in output volt-
age and load current.
The MAX8500–MAX8504 are available in a 12-lead
4mm x 4mm thin QFN package (0.8mm max height).
19-2641; 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.
INPUT 2.6V TO 5.5V
10 F
N-CDMA/W-CDMA Cellular Phones
Wireless PDAs and Modems
SKIP
SHDN
REF
Typical Operating Circuit
1MHz
OSC
BATT
________________________________________________________________ Maxim Integrated Products
COMP
PWM Buck Converters with Bypass FET
PWM
General Description
R
8.2k
C
1000pF
C
C
PGND
LX
MAX8500-
MAX8503
LDO
4.7 H
Applications
g
m
GND
OUT
OUTPUT 0.4V TO V
for N-CDMA/W-CDMA Handsets
REFIN
DAC
4.7 F
BATT
BATT
typ)
.
*Future product—contact factory for availability.
MAX8500ETC
MAX8501ETC*
MAX8502ETC*
MAX8503ETC
MAX8504ETC
Integrated Bypass PFET
150mV Dropout at 600mA Load (Regardless of
External Inductor)
Dynamically Adjustable Output from 0.4V to
V
Externally Fixed Output from 1.25V to 2.5V with
Digitally Controlled High-Power Bypass Mode
(MAX8504)
1MHz Fixed-Frequency PWM Switching
600mA Guaranteed Output Current
10% to 100% Duty-Cycle Operation
Low Quiescent Current
12-Pin Thin QFN (4mm x 4mm, 0.8mm max Height)
BATT
PART
280µA (typ) in Normal Mode
3.3mA (typ) in PWM Mode
0.1µA (typ) in Shutdown Mode
REFIN
GND
(FB)
REF
-40 C to +85 C
-40 C to +85 C
-40 C to +85 C
-40 C to +85 C
-40 C to +85 C
TEMP RANGE
1
2
3
Thin QFN 4mm x 4mm
COMP
Ordering Information
SHDN
12
4
( ) MAX8504 ONLY
MAX8500–
MAX8504
BATT
(HP)
Pin Configuration
SKIP
11
5
PGND
OUT
10
PIN-
PACKAGE
12 Thin QFN
12 Thin QFN
12 Thin QFN
12 Thin QFN
12 Thin QFN
6
9
8
7
Features
BATT
BATTP
LX
MARK
AABQ
AABU
AABS
TOP
1

Related parts for MAX8500

MAX8500 Summary of contents

Page 1

... The MAX8500–MAX8504 are available in a 12-lead 4mm x 4mm thin QFN package (0.8mm max height). N-CDMA/W-CDMA Cellular Phones Wireless PDAs and Modems Typical Operating Circuit INPUT 2 ...

Page 2

... Continuous Power Dissipation (T 12-Lead Thin QFN (derate 16.9mW/ C above +70 C) .1349mW Operating Temperature Range ...........................- +85 C Junction Temperature ......................................................+150 C + 0.3V) BATT Storage Temperature Range .............................- +150 C Lead Temperature (soldering, 10s) .................................+300 C = 1.932V (MAX8500, MAX8502), V REFIN A CONDITIONS BATT V rising, 1% hysteresis UVLO BATT ...

Page 3

... Logic Input Low Logic Input Current THERMAL SHUTDOWN Thermal-Shutdown Temperature Thermal-Shutdown Hysteresis Note 2: Specifications to -40°C are guaranteed by design and not subject to production test. Note 3: Guaranteed by design, not production tested. _______________________________________________________________________________________ for N-CDMA/W-CDMA Handsets = 1.932V (MAX8500, MAX8502), V REFIN CONDITIONS I = 180mA 3.6V LX BATT N ...

Page 4

... SKIP = GND LOAD 50 2.5 3.0 3.5 4.0 4.5 5.0 5.5 INPUT VOLTAGE (V) MAX8504 DROPOUT VOLTAGE vs. LOAD CURRENT 0.25 0.20 0.15 0.10 0. 3.5V OUT HP = BATT 0 0 100 200 300 400 500 600 700 800 900 1000 LOAD CURRENT (mA) MAX8500/MAX8503 ENTERING REGULATOR DROPOUT REGION 3.50 3.45 3.40 3.35 3.30 3. 3.4V; OUT SKIP = BATT 3.20 0 300 600 900 1200 1500 LOAD CURRENT (mA) ...

Page 5

... MAX8500 toc14 V 2V/div V AC-COUPLED 5mV/div V = 3.6V 0.4V IN OUT LOAD = 10 400ns/div HEAVY-LOAD SWITCHING WAVEFORM MAX8500 toc12 V = 3.6V 3.3V IN OUT LOAD = 10 400ns/div LIGHT-LOAD SWITCHING WAVEFORM IN SKIP MODE MAX8500 toc15 3.6V 0.4V IN OUT LOAD = 10 OUT 2 s/div V LX 2V/div V OUT AC-COUPLED 2mV/div V LX 2V/div V OUT AC-COUPLED 20mV/div ...

Page 6

... OUT LOAD = 600mA 100 s/div REFIN TRANSIENT RESPONSE MAX8500 toc17 REFIN 1V/div V OUT SKIP = BATT 1V/div SKIP = GND V = 3.6V, LOAD = REFIN = 0.455 TO 1.932V 20 s/div LINE-TRANSIENT RESPONSE MAX8500 toc19 V OUT AC-COUPLED 10mV/div V = 3.5V TO 4.5V 1.5V IN OUT LOAD = 500mV/div 100 s/div V OUT AC-COUPLED ...

Page 7

... V with a settling time <30µs (Figure 1). The BATT MAX8504 uses external feedback resistors to set the out- put voltage from 1.25V to 2.5V. The MAX8500–MAX8504 operate at a high 1MHz switching frequency that reduces external component _______________________________________________________________________________________ for N-CDMA/W-CDMA Handsets Ground Reference Bypass Pin. Connect a 0.22µF ceramic capacitor from this pin to GND. ...

Page 8

... PWM Buck Converters with Bypass FET for N-CDMA/W-CDMA Handsets INPUT 2. Figure 1. MAX8500–MAX8503 Functional Diagram and Typical Operating Circuit The MAX8500–MAX8504 use a fixed-frequency, current- mode, PWM controller capable of achieving 100% duty cycle. Current-mode feedback provides cycle-by-cycle current limiting, superior load and line response, as well as overcurrent protection for the internal MOSFET and rectifier ...

Page 9

... The MAX8500–MAX8504 do not operate with battery voltages below the UVLO threshold of 2.35V (typ). The output remains off until the supply voltage exceeds the UVLO threshold. This guarantees the integrity of the output voltage regulation ...

Page 10

... PA is lowered from low as 0.4V to greatly reduce battery cur- BATT rent. Figure 3 shows the typical CDMA PA load profile. The use of DC-to-DC converters such as the MAX8500– MAX8503 dramatically extends talk time in these appli- cations. The MAX8500–MAX8503s’ output voltage is dynamically adjustable from 0. ...

Page 11

... I OUT I V RMS OUT V IN Compensation, Stability, and Output The MAX8500–MAX8504 are externally compensated by placing a resistor and a capacitor (see Figures 1 and 2, R and series from COMP to GND additional capacitor (C ) may be required from COMP f to GND if high-ESR output capacitors are used. The capacitor integrates the current from the transconduc- tance amplifier, averaging output capacitor ripple ...

Page 12

PWM Buck Converters with Bypass FET for N-CDMA/W-CDMA Handsets Table 1. Suggested Inductors PART MANUFACTURER NO. Murata LQH3C Sumida CDRH2D18 Taiyo Yuden LBLQ2016 Toko D312F Table 2. Manufacturers of Suggested Components MANUFACTURER PHONE Murata 770-436-1300 847-956-0666 (USA) Sumida 81-3-3607-5111 (Japan) ...

Page 13

PWM Buck Converters with Bypass FET (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information www.maxim-ic.com/packages.) ______________________________________________________________________________________ for N-CDMA/W-CDMA Handsets Package Information PACKAGE OUTLINE 12,16,20,24L QFN THIN, ...

Page 14

PWM Buck Converters with Bypass FET for N-CDMA/W-CDMA Handsets (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information www.maxim-ic.com/packages.) Maxim cannot assume responsibility for use of any ...

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