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MAX1686EUA+-MAX1686HEUA+-MAX1686HEUA+T
3V to 5V Regulating Charge Pumps for SIM Cards
General DescriptionThe MAX1686 provides power for dual-voltage sub-
scriber ID module (SIM) cards in portable applications
such as GSM cellular phones. Designed to reside in the
portable unit (cellular phone handset), the 1MHz charge
pump converts a 2.7V to 4.2V input to regulated 5V out-
put. The MAX1686H has a nominal output voltage of
5.0V, while the MAX1686 is set to 4.75V to reduce SIM-
card current drain. The charge pump has only 45μA qui-
escent supply current, which reduces to 3μA when a
3V-capable SIM card is being powered and the charge
pump is disabled. An internal input/output shorting
switch provides power for 3V SIM cards.
The MAX1686/MAX1686H require only three external
capacitors around their space-saving, thin (1mm) 8-pin
μMAX packages.
ApplicationsGSM Cellular Phones
PCS Phones
Portable POS Terminals
Personal Communicators
Feature2.7V to 4.2V Input Range 12mA min Charge-Pump Output Current 45μA Quiescent Supply Current0.1μA Supply Current in Shutdown Mode5.0V Regulated Charge-Pump Output (MAX1686H)
4.75V Regulated Charge-Pump Output (MAX1686)Input-Output Shorting Switch for 3V CardsSmall External Components
(Uses a 0.047μF, 0.1μF, and a 2.2μF Capacitor)Output Driven to Ground in Shutdown ModeSuper-Small 8-Pin μMAX PackageSoft-Start and Short-Circuit ProtectionV to 5V Regulating
Charge Pumps for SIM CardsOUT
CXP
CXN
PGNDGND
SHDN
3/5
MAX1686
MAX1686H
μMAX
TOP VIEW
MAX1686
MAX1686H
CXNCXP
GNDPGND
CIN
INPUT
2.7V TO 4.2V
OUTPUT
VIN OR 5V/20mA
COUT
SHDN
3/5
OUT
Typical Operating Circuit19-1376; Rev 1; 12/98
PART
MAX1686EUA-40°C to +85°C
TEMP. RANGEPIN-PACKAGE8 μMAX
Pin Configuration
Ordering Information
MAX1686HEUA-40°C to +85°C8 μMAX
V to 5V Regulating Charge Pumps for SIM Cards
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VIN= VSHDN= 3.3V, 3/5= GND, CX= 0.22μF, COUT = 10μF (see Applications Informationsection to use smaller capacitors), = TMINto TMAX, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
IN, OUT, SHDN, 3/5to GND.....................................-0.3V to +6V
CXP to GND..............................................-0.3V to (VOUT + 0.3V)
CXN to GND................................................-0.3V to (VIN+ 0.3V)
PGND to GND......................................................-0.3V to + 0.3V
OUT Short Circuit to GND..........................................Continuous
IN-to-OUT Current...............................................................50mA
Continuous Power Dissipation (TA= +70°C )
8-Pin μMAX (derate 4.1mW/°C above +70°C).............330mW
Operating Temperature Range
MAX1686EUA/MAX1686HEUA........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +165°C
Lead Temperature (soldering, 10sec).............................+300°C
PARAMETERCONDITIONSMINTYPMAXUNITSInput Voltage Range 2.74.2V
Input Undervoltage-Lockout
Threshold Voltage0.81.21.6V
Quiescent Supply Current
Charge pump enabled,
no load, 3/5= GNDμA
Charge pump disabled, no load, 3/5= IN
Shutdown Supply CurrentVIN = 3.6V, SHDN= GND0.15OUT Output Voltage
V3/5= VIN= 3.0V2.55Ω
OUT Short-Circuit Current3/5= GND or IN20100200mA
Logic Input Low VoltageSHDN, 3/50.5 ·VIN0.3 ·VINV
Logic Input High VoltageSHDN, 3/50.7 ·VIN0.5 ·VINV
Logic Input Leakage CurrentSHDN, 3/5= GND or IN0.11μA
OUT Discharge Switch On-Resistance3/5= GND or IN, SHDN= GND80200Ω
IN-to-OUT Switch On-Resistance= +25°C80010001200
Note 1:Electrical specifications are measured by pulse testing and are guaranteed for a junction temperature within the operating
temperature range, unless otherwise noted. Limits are 100% production tested at TA= +25°C. Limits over the entire operat-
ing temperature range are guaranteed through correlation using Statistical Quality Control (SQC) methods and are not pro-
duction tested.
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.= +25°C4510010
Charge-Pump FrequencyTA= -40°C to +85°C7001300kHz= -40°C to +85°C150
3/5= INVIN
MAX1686
MAX1686H
VIN= 2.7V to 4.2V,
load = 0 to 12mA
V to 5V Regulating Charge Pumps for SIM CardsEFFICIENCY vs. LOAD CURRENT
(5V MODE)
AX1686-01
LOAD CURRENT (mA)
(%
VIN = 3.6V
VIN = 2 .7VVIN = 3.3V
EFFICIENCY vs. INPUT VOLTAGE
(5V MODE)AX1686-TO
INPUT VOLTAGE (V)
(%23456
ILOAD = 10mAILOAD = 1mA
NO-LOAD INPUT CURRENT
vs. INPUT VOLTAGE (3V MODE)
AX1686-03
INPUT VOLTAGE (V)
(μ5
10,0002146
NO-LOAD INPUT CURRENT
vs. INPUT VOLTAGE (5V MODE)AX1686-04
INPUT VOLTAGE (V)
(μ5231456
OUTPUT VOLTAGE
vs. INPUT VOLTAGE (3V MODE)INPUT VOLTAGE (V)
(V
NO LOAD
OUTPUT VOLTAGE
vs. LOAD CURRENT (3V MODE)
AX1686-05
LOAD CURRENT (mA)
(V
MAX1686 OUTPUT VOLTAGE
vs. LOAD CURRENT (5V MODE)
AX1686-06
LOAD CURRENT (mA)
(V
VIN = 2.7V
VIN = 3 .3V
VIN = 3.6V231456
OUTPUT VOLTAGE
vs. INPUT VOLTAGE (5V MODE)AX1686-08
INPUT VOLTAGE (V)
(V
NO LOAD
MAX1686
MAX1686H
2.5μs/div
OUTPUT WAVEFORM
(ILOAD = 10mA)AX1686-09
VOUT
(20mV/div)
5V MODE, AC COUPLED,
Typical Operating Characteristics(See Typical Operating Circuit, CIN= 0.47μF, CX= 0.22μF, COUT= 10μF, VIN= 3.3V, TA= +25°C, unless otherwise noted.)
V to 5V Regulating Charge Pumps for SIM Cards
Typical Operating Characteristics (continued)(See Typical Operating Circuit, CIN= 0.47μF, CX= 0.22μF, COUT= 10μF, VIN= 3.3V, TA= +25°C, unless otherwise noted.)
25µs/div
OUTPUT WAVEFORM
(ILOAD = 1mA)AX1686-10
VOUT
(20mV/div)
5V MODE, AC COUPLED,
COUT = 10μF 0.1μF
2.5ms/div
LINE-TRANSIENT RESPONSEMAX1686-11
VIN
(500mV/div)
VIN = 2.8V to 3.3V, ILOAD = 10mA, 5V MODE,
AC COUPLED
VOUT
(50mV/div)
2.5ms/div
LOAD-TRANSIENT RESPONSEAX1686-12ILOAD
(10mA/div)
ILOAD = 0 TO 10mA, 5V MODE, AC COUPLED
VOUT
(50mV/div)
250μs/div
START-UP WAVEFORM
(3V MODE, RL = 500Ω)AX1686-13SHDN
(5V/div)
VOUT
(1V/div)
1ms/div
SHUTDOWN WAVEFORM
(3V MODE, NO LOAD)MAX1686-16SHDN
(5V/div)
VOUT
(1V/div)
250μs/div
START-UP WAVEFORM
(5V MODE, RL = 500Ω)MAX1686-14SHDN
(5V/div)
VOUT
(1V/div)
250μs/div
3V MODE TO 5V MODE
WAVEFORM (RL = 500Ω)MAX1686-153/5
(5V/div)
VOUT
(1V/div)
1ms/div
SHUTDOWN WAVEFORM
(5V MODE, NO LOAD)AX1686-17SHDN
(5V/div)
VOUT
(1V/div)
500μs/div
5V MODE TO 3V MODE
WAVEFORM (NO LOAD)AX1686-183/5
(5V/div)
VOUT
(1V/div)
V to 5V Regulating Charge Pumps for SIM Cards
NAMEFUNCTION3/53V/5V Select Input. When low, the output is regulated at 4.75V for MAX1686, 5.00V for MAX1686H. When
high, the output is shorted to the input. SHDNActive-Low Shutdown Input. SHDN= GND is off. Output is actively pulled low in shutdown.
PININSupply Input Pin. Can range from 2.7V to 4.2V. Bypass to ground with a ceramic capacitor.GNDGround PinOUTPower Output. Bypass to GND with an output filter capacitor.CXPPositive Terminal of the Charge-Pump Transfer CapacitorCXNNegative Terminal of the Charge-Pump Transfer CapacitorPGNDPower Ground. Connect to GND through a short trace.
Pin Description
_______________Detailed DescriptionThe MAX1686/MAX1686H charge pumps provide two
modes of operation: 3V mode or 5V mode. The devices
consist of an error amplifier, a 1.23V bandgap refer-
ence, an internal resistive feedback network, a 1MHz
oscillator, high-current MOSFET drivers and switches,
and a power-management block as shown in the
Functional Diagram(Figure 1). In 3V mode (3/5= IN),
the inputis connected to the output through a 2.5Ω
switch. In 5V mode (3/5=GND), the MAX1686’s output
voltage is regulated at 4.75V (5.00V for the MAX1686H)
with a 2.7V to 4.2V input and can deliver more than
12mA of load current.
Designed specifically for compact applications, these
regulators require only three small external capacitors.
The Skip Mode control scheme provides high efficiency
over a wide output current range. The devices offer a
shutdown feature which actively discharges the output
to ground and reduces the supply current to less than
MAX1686
MAX1686H
POWER
MANAGEMENTDIS
OSC
CXPCXN
SHDN
3/5
1.23V
GND
PGNDS2
PWROK
OUT
Figure 1. Functional Diagram
V to 5V Regulating Charge Pumps for SIM Cards1μA. Other features include soft-start, undervoltage
lockout, and short-circuit protection.
Charge-Pump ControlFigure 2 shows an idealized, unregulated charge-pump
voltage doubler. The oscillator runs at a 50% duty
cycle. During one half of the period, the transfer capac-
itor (CX) charges to the input voltage. During the other
half, the doubler stacks the voltage across CX and the
input voltage, and transfers the sum of the two voltages
to the output filter capacitor (COUT). The MAX1686 uses
Skip Mode control to regulate its output voltage and to
achieve good efficiency over a large output current
range. When the comparator detects that the output
voltage is too low, the 1MHz oscillator is enabled andis switched. When the output voltage is above regu-
lation, the oscillator is disabled and CXis connected at
the input.
Soft-StartIn the 5V mode (3/5= GND), the start-up current is lim-
ited by the soft-start control to typically 200mA, inde-
pendent of the load. Until the output voltage reaches
VIN / 2, the input is connected to the output through a
50Ωseries P-channel MOSFET and the charge pump
is disabled. For VIN / 2 < VOUT < 4.75V (5.00V for
MAX1686H) and for a maximum of 2ms the charge
pump is active, but RON of the switch S2 is limited to
50Ω. This limits typical current surges associated with
charge pumps at start-up. When soft-start is complete,
VOUT > 4.75V (5.00V for MAX1686H) or 2ms (whichever
occurs first), switch S2’s on-resistance is decreased to
minimize losses.
In 3V mode (3/5= IN), the start-up current is limited by
the 50Ωseries P-channel MOSFET connected between
IN and OUT until the output voltage reaches VIN / 2. For
VOUT > VIN / 2, RONis reduced to 2.5Ω.
With a 500Ωload the device turns on in less than 1.5ms
(see Typical Operating Characteristicsfor graphs of
start-up waveforms).
Shutdown ModeDriving SHDNlow places the device in shutdown mode,
which disables the oscillator, the control logic, and the
reference. Placing the device in shutdown mode
reduces the no-load supply current to less than 1μA; the
output is actively discharged through the internal N-
channel FET and disconnected from the input. In normal
operation, SHDNis driven high or connected to IN.
Applications Information
Capacitor SelectionThe MAX1686 requires only three external capacitors.
The capacitor values are closely linked to the output
current capability, noise, and switching frequency. The
1MHz oscillator frequency minimizes capacitor size
compared to lower-frequency charge pumps.
Generally, the transfer capacitor (CX) will be the
smallest, the input capacitor (CIN) will be twice the size
of CX, and the output capacitor (COUT) can be from 10
to 50 times CX. The suggested capacitor values are
CIN= 0.1μF, CX= 0.047μF, and COUT= 2.2μF as
shown in Figure 3. For input voltages as low as 2.7V,
the following values are recommended: CIN= 0.47μF,= 0.22μF, and COUT= 10μF. Table 1 lists the perfor-
OSC
CXPCXN
GNDS2
OUT
CINCOUT
Figure 2. Unregulated Voltage Doubler
MAX16863857
CXNCXP
GNDPGND
CIN
0.1μF
INPUT
2.85V TO 4.2V
OUTPUT
VIN OR 4.75V AT 20mA
0.047μF
COUT
2.2μF
(CERAMIC)
SHDN
3/5
OUT
Figure 3. Standard Application Circuit
