MAX1687EUE+T-MAX1688ESA+-MAX1688EUE+ Fast Delivery |IC PHOENIX CO.,LIMITED

MAX1687EUE+T ,Step-Up DC-DC Converters with Precise, Adaptive Current Limit for GSMfeatures a more advanced, adaptive constant-recharge-time algorithm that maximizes battery life. Th ..
MAX1688ESA+ ,Step-Up DC-DC Converters with Precise, Adaptive Current Limit for GSMapplications such as GSM ♦ 90% Efficiencycell phones and wireless LANs, where the RF power♦ Interna ..
MAX1688EUE ,Step-Up DC-DC Converters with Precise / Adaptive Current Limit for GSMFeatures' Low 450mA Peak Battery Current The MAX1687/MAX1688 step-up DC-DC converters deliv-Provide ..
MAX1688EUE ,Step-Up DC-DC Converters with Precise / Adaptive Current Limit for GSMELECTRICAL CHARACTERISTICS(V = V = +3V, V = 1V (MAX1687), V = 1V (MAX1688), V = 1.5V, V = 6V, T = 0 ..
MAX1688EUE+ ,Step-Up DC-DC Converters with Precise, Adaptive Current Limit for GSMELECTRICAL CHARACTERISTICS(V = V = +3V, V = 1V (MAX1687), V = 1V (MAX1688), V = 1.5V, V = 6V, T = 0 ..
MAX16903RA33/V+TCE ,2.1MHz, High-Voltage, 1A Mini-Buck ConverterApplications• Forced Fixed-Frequency Operation • External Frequency SynchronizationOrdering Informa ..
MAX4489AUA+T ,SOT23, Low-Noise, Low-Distortion, Wide-Band, Rail-to-Rail Op AmpsApplicationsOrdering InformationADC BuffersPIN- TOPDAC Output AmplifiersPART TEMP RANGEPACKAGE MARK ..
MAX448CPD ,Single/Dual/Quad High-Speed / Fast-Settling / High Output Current Operational Amplifierapplications where accuracy must be maintained.
MAX448CSD ,Single/Dual/Quad High-Speed / Fast-Settling / High Output Current Operational AmplifierFeaturesThe MAX408/428/448 are high speed general purpose' Fast Settling Time: ±0.1% In 150nsmonol ..
MAX4490AUK ,Low-Cost, High-Slew-Rate, Rail-to-Rail I/O Op Amps in SC70MAX4490/MAX4491/MAX449219-1525; Rev 2; 4/01Low-Cost, High-Slew-Rate, Rail-to-Rail I/O Op Amps in SC ..
MAX4490AUK+T ,Low-Cost, High-Slew-Rate, Rail-to-Rail I/O Op Amps in SC70FeaturesThe MAX4490/MAX4491/MAX4492 single/dual/quad,♦ 2.7V to 5.5V Single-Supply Operation®low-cos ..
MAX4490AXK ,Low-Cost, High-Slew-Rate, Rail-to-Rail I/O Op Amps in SC70ApplicationsMAX4491AUA -40°C to +125°C 8 µMAX —Sensor AmplifiersMAX4492AUD -40°C to +125°C 14 TSSOP ..

MAX1687EUE+T-MAX1688ESA+-MAX1688EUE+
Step-Up DC-DC Converters with Precise, Adaptive Current Limit for GSM
neral DescriptionThe MAX1687/MAX1688 step-up DC-DC converters deliv-
er up to 2W from a single Li-Ion or three NiMH cells. The
devices are ideal for burst-load applications such as GSM
cell phones and wireless LANs, where the RF power
amplifiers require short, high current bursts. The
MAX1687/MAX1688 reduce battery surge current by slow-
ly charging a reservoir capacitor, which supplies the nec-
essary peak energy for the load current burst. As a result,
the peak battery current is limited, thus maximizing battery
life and minimizing battery voltage sag and transient dips.
An internal synchronous rectifier provides over 90% con-
version efficiency and eliminates the need for an external
Schottky diode. A logic shutdown mode reduces the shut-
down current to only 3μA. The devices can be disabled
during current bursts (RF transmit mode) to eliminate
switching noise.
The switching frequency of the MAX1687/MAX1688, con-
trolled by the selected inductor, can exceed 1MHz. Two
external resistors set the output voltage from 1.25V to 6V.
The MAX1687 controls peak battery current, while the
MAX1688 features a more advanced, adaptive constant-
recharge-time algorithm that maximizes battery life. The
MAX1687/MAX1688 are available in thin 16-pin TSSOP
(1.1mm max height) or standard 8-pin SO packages.
Applications
GSM Phones
Wireless Handsets
PC Cards (PCMCIA)aturesLow 450mA Peak Battery Current
Provides 2A, 5V GSM Burst90% EfficiencyInternal Power MOSFETs and Current-Sense
ResistorOutput Disconnects from Input During Shutdown3μA Shutdown CurrentPrecise Voltage-Controlled Current Limit
(MAX1687)Adaptive Constant-Recharge-Time Capability
(MAX1688)1.25V to 6V Adjustable Output 2.7V to 6V Input Range
(1 Li-Ion cell or 3 NiMH cells)Switching Frequency Can Exceed 1MHzStandby Mode Disables DC-DC During
Transmission BurstLow Inrush Current at Start-Upep-Up DC-DC Converters wit
Precise, Adaptive Current Limit for GSMOUT
OUT
LX2
LX2
PGND
PGND
AGND
TOP VIEW
MAX1687
MAX1688
TSSOP
LX1
LX1
LIM [CHG]
REF
N.C.
[ ] ARE FOR MAX1688
MAX1687
MAX1688
VOUT
UP TO 6VOUTINLX1LX2ON
2.7V TO 6V
OFF
0 TO 1V
CONTROL INPUT
1 Li-lon
3 NiMH
3 ALKALINE
(LIM)
REF
[CHG]
( ) ARE FOR MAX1687
[ ] ARE FOR MAX1688
GND
Typical Operating Circuit
19-1426; Rev 0; 2/99
PART*
MAX1687EUE
MAX1687ESA
MAX1688EUE-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
TEMP. RANGEPIN-PACKAGE
16 TSSOP
8 SO
16 TSSOP
Pin Configurations
Ordering Information
MAX1688ESA-40°C to +85°C8 SO
Pin Configurations continued at end of data sheet.
†Pg
*Ug.
EVALUATION KIT MANUAL
FOLLOWS DATA SHEET
ep-Up DC-DC Converters with Precise, Adaptive Current Limit for GSM
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VIN= VON= +3V, VLIM= 1V (MAX1687), VCHG= 1V (MAX1688), VFB= 1.5V, VOUT= 6V, TA = 0°C to +85°C, unless otherwise noted.
Typical values are at TA= +25°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.
IN, ON, LX1, CHG, LIM, FB, OUT, REF to GND.......-0.3V to +7V
LX2 to GND..............................................................-0.3V to +8V
IN, LX1 Average Current..........................................................1A
Continuous Power Dissipation (TA= +70°C)
TSSOP (derate 5.7mW/°C above +70°C)....................457mW
SO (derate 5.88mW/°C above +70°C).........................471mW
Operating Temperature Range...........................-40°C to +85°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10sec)............................+300°C
IN rising, 1% hysteresis
VFB= 0, VOUT= 3V (MAX1688)
VFB= 1.125V, VOUT= 3V (MAX1688)
VFBrising, 2% hysteresis
IREF= 0 to 10μA
VFB= 1.5V
Shutdown, VIN= 4.2V, LX2 connected to LX1,
VOUT= 0, ON = GND
VLIM= VCHG= 1V
CONDITIONS
0.7440.80.856Peak CurrentVREF6Output Voltage Range2.42.52.62.76Input Voltage Range
Input Undervoltage Lockout60110ICHGSource Current
mmho0.180.20.22gmFBFB Transconductance1.2121.2501.288FB Set Voltage1.2251.251.275VREFReference Voltage24
Input Supply CurrentμA310
UNITSMINTYPMAXSYMBOLPARAMETER
VLIM= VCHG= 1V
VLIM= VCHG= 0.65V
VIN= 2.7V
VLIM= 1V
VON= 0 or 3V
VIN= 2.7V
VIN= 6V
VIN= 4.2V
VFB= 1.5V
VIN= 2.7VΩ0.30.7P-Channel On-Resistance0.10.18RSENSESense Resistor 170200230IRIPPLE0.460.50.54IPEAK
Ripple Current0.40.8N-Channel On-Resistance
0.020.1ILIM
0.020.1ION0.6VIL1.8
ON Input Low Voltage
0.050.2IFB
Input Current
VIN= VLX2= 6V, VOUT= VON= 0
VIN= 4V, VFB = 0, VOUT = 00.05103070Precharge On-Resistance
LX2 Leakage Current0.71.21.8tDELAYShutdown Delay
VIHON Input High Voltage= 0°C to +85°C= +25°C
ep-Up DC-DC Converters witPrecise, Adaptive Current Limit for GSM
ELECTRICAL CHARACTERISTICS
(VIN= VON= +3V, VLIM= 1V (MAX1687), VCHG= 1V (MAX1688), VFB= 1.5V, VOUT= 6V, TA= -40°C to +85°C, unless otherwise noted.)
(Note 1)
Note 1:Specifications to -40°C are guaranteed by design, not production tested.
VLIM= VCHG= 1V
VLIM= VCHG = 0.65V
IIN
IN rising, 1% hysteresis
VFB= 1.125V, VOUT= 3V (MAX1688)
FB rising, 2% hysteresis
IREF= 0 to 10μA
VFB= 1.5V
Shutdown VIN= 4.2V, LX2 connected to LX1,
VOUT= 0, ON = GND
VLIM = VCHG= 1V
CONDITIONS145240IRIPPLERipple Current0.440.57IPEAK0.18RSENSESense Resistor
0.730.90Peak Current2.35 2.652.76Input Voltage Range
Input Undervoltage Lockout
mmho0.160.24gmFBFB Transconductance1.201.30FB Set Voltage1.2121.288VREFReference Voltage0.62TDELAYShutdown Delay5
ISHDNInput Supply CurrentμA10
UNITSMINTYPMAXSYMBOLPARAMETER
VIN= 4V, VFB = 0, VOUT = 0
VIN= 2.7V
VIN= 2.7V70Precharge On-Resistance0.70.8N-Channel On-Resistance
P-Channel On-Resistance
Typical Operating Characteristics
(VIN= +3.3V, VOUT= 5V, VLIM = 1V, Figures 6b and 7, TA= +25°C, unless otherwise noted.)15020050100250300350
EFFICIENCY vs. DC LOAD CURRENT
(VOUT = 5.5V)
X1687/88 toc01
LOAD CURRENT (mA)
(%
VIN = 5V
VIN = 3.3V
VIN = 2.7V
VIN = 6V15005001000200025003000
EFFICIENCY vs. GSM BURST LOAD
(VOUT = 5.5V)
AX1687/88 toc02
LOAD CURRENT (mA)
(%
VIN = 5V
VIN = 3.3V
VIN = 2.7V
VIN = 6V
EFFICIENCY vs. LOAD CURRENT
(VIN = 2.7V, VOUT = 3.3V)
AX1687/88 toc03
LOAD CURRENT (mA)
(%
VIN= 2.7VV0.6VILON Input Low VoltageVIN= 6V
VIN= 4.2VVIHON Input High Voltage1.8
1.5VREF6Output Voltage Range
ep-Up DC-DC Converters with Precise,Adaptive Current Limit for GSM
_____________________________Typical Operating Characteristics (continued)
(VIN= +3.3V, VOUT= 5V, VLIM = 1V, Figures 6b and 7, TA= +25°C, unless otherwise noted.)
MAX1688
IPEAK vs. VOUT DROOP
X1687/88 toc09
VOUT DROOP (mV)
(m
RCHG = 40.2k
MAX1688 PEAK INDUCTOR CURRENT
vs. RCHG (1A GSM LOAD)
AX1687/88 toc10
RCHG (kW)
IN
(m
MAX1688 PEAK BATTERY CURRENT
vs. RCHG (1A GSM LOAD)
1687/88 toc04
RCHG (kW)
(m
TEMPERATURE (°C)
(m
NO-LOAD BATTERY INPUT CURRENT vs.
TEMPERATURE (VOUT = 5V, VLIM = 1V )
X1687/88 toc05
VIN = 5V
VIN = 3.3V
VIN = 2.7V
VIN = 6V
REFERENCE VOLTAGE vs. REFERENCE
CURRENT (VIN = 3.3V, VOUT = 5V)
1687/88 toc06
IREF (mA)
(V
TEMPERATURE (°C)
(V
REFERENCE VOLTAGE vs. TEMPERATURE
(VIN = 3.3V, VOUT = 5V)
AX1687/88 toc07
SWITCHING FREQUENCY vs. INDUCTANCE
(VIN = 3.3V, VOUT = 5V,
ILOAD = 100mA, VLIM = 1V)
AX1687/88 toc08
INDUCTANCE (mH)
(kH
800
ep-Up DC-DC Converters witPrecise, Adaptive Current Limit for GSM
Typical Operating Characteristics (continued)
(VIN= +3.3V, VOUT= 5V, VLIM = 1V, Figures 6b and 7, TA= +25°C, unless otherwise noted.)
500mA/div
500mA/div
200mV/div
VOUT
1ms/div
ILX
ILOAD
MAX1688
SWITCHING WAVEFORMS
(GSM PULSED LOAD 1A, RCHG = 40.2kW)
MAX1687/88 toc11
RCHL = 40.2kW, L = 10mH
200mA/div
VLIM = 1V
VLIM = 0s/div
ILX
ILX
INDUCTOR CURRENT
MAX1687/88 toc13
200mA/div
1V/div
IBATTERY
VON
MAX1687/88 toc15VON vs. BATTERY CURRENT
2V/div
1V/div
VON
VOUT
MAX1687/88 toc14
POWER-UP WAVEFORM
(RLOAD = 15W COUT = 2000mF)
500mA/div
500mA/div
200mV/div
VOUT
1ms/div
ILX
ILOAD
MAX1688
SWITCHING WAVEFORMS
(GSM PULSED LOAD 1A, RCHG = 18kW)
MAX1687/88 toc12
RCHG = 18kW, L = 10mH
500mA/div
100mV/div
VOUT
500ms/div
ILX
SWITCHING WAVEFORMS
(FIXED ILOAD = 300mA)
MAX1687/88 toc10a
Detailed Description
The MAX1687 and MAX1688 ICs supply power ampli-
fiers inGSM applications where limited input current
surge is desirable. For example, GSM systems require
high-power, 12% duty-cycle RF bursts. Synchronizing
the MAX1687/MAX1688 to enter standby mode during
these RF bursts eliminates battery surge current and
minimizes switching noise to the power amplifier. In
standby mode, the charged output reservoir capacitor
delivers power to the power amplifier. Between each
burst, the DC-DC converter switches on to charge the
output capacitor. To improve efficiency and reduce peak
battery current, the MAX1687/MAX1688 provide a volt-
age-controlled current limit. The MAX1688 is a MAX1687
with added self-regulating circuitry that recharges the
reservoir capacitor in a fixed time (Figure 1).
Start-Up Sequence
In a conventional DC-DC converter, when high current
is required by the load, the battery voltage droops due
to battery series resistance. This may cause other cir-
cuitry that depends on the battery to malfunction or be
reset. The MAX1687/MAX1688 prevent battery voltage
droop by charging the reservoir capacitor during sys-
tem off-time and isolate the battery from the output dur-
ing high current demand. The MAX1687/MAX1688 are
gentle to the battery during initial power-up, as well.ep-Up DC-DC Converters with
Precise, Adaptive Current Limit for GSM
Pin Description
PIN
NAMEFUNCTIONMAX1688MAX1687
11, 12
13, 14
15, 16
3, 4
1, 2
TSSOP
GND
AGND
PGND
LX2
OUT
REF
N.C.
CHG
LIM
LX1
Ground
Analog Ground
Power Ground
N-Channel and P-Channel MOSFET Drain
Output
Feedback Input. Connect a resistor-divider from OUT to GND to
set the output voltage. FB regulates to a nominal 1.25V.
Reference Voltage Output. 1.25V nominal.
No Connection. Not internally connected.
Logic ON/OFF Input. When ON is high, the device operates in
normal mode. When ONgoes low, the device goes into standby
mode. If ON remains low for greater than 1.2ms, the device shuts
down (see Standby/Shutdownsection). The supply current falls to
3μA in shutdown mode.
Constant-Recharge-Time Input. Set the recharge time of the out-
put reservoir capacitor by connecting a resistor from CHG to GND
(see Applications Informationsection).
Voltage-Controlled Current-Limit Adjust Input. Apply a voltage
between 0 and 1V to vary the current limit. LIM is internally
clamped to 1.25V.
Internal Current-Sense Resistor Output. Connect the inductor
between LX1 and LX2.
Supply Voltage Input. Connect Battery to IN. Bypass to GND with
a 47μF minimum capacitor.—610—11, 12—13, 14715, 168647—8—95——533, 421, 21TSSOP

Partno	Mfg	Dc	Qty	Available	Descript
MAX1687EUE+T	MAXIX	N/a	872	avai	Step-Up DC-DC Converters with Precise, Adaptive Current Limit for GSM
MAX1688ESA+ \|MAX1688ESA	MAXIM	N/a	589	avai	Step-Up DC-DC Converters with Precise, Adaptive Current Limit for GSM
MAX1688EUE+ \|MAX1688EUE	MAXIM	N/a	13	avai	Step-Up DC-DC Converters with Precise, Adaptive Current Limit for GSM