MAX667ESA ,+5V/Programmable Low-Dropout Voltage Regulatorapplications where the input voltages______________Ordering Informationare above +3.5V. Choose the ..
MAX667ESA ,+5V/Programmable Low-Dropout Voltage RegulatorGeneral Description ________
MAX667ESA+ ,+5V Programmable, Low-Dropout Voltage RegulatorFeaturesThe MAX667 low-dropout, positive, linear voltage regu-♦ 350mV Max Dropout at 200mAlator sup ..
MAX667ESA+T ,+5V Programmable, Low-Dropout Voltage RegulatorELECTRICAL CHARACTERISTICS(GND = 0V, V = +9V, V = +5V, C1 = 10µF, unless otherwise noted.)IN OUT T ..
MAX667MJA ,+5V/Programmable Low-Dropout Voltage RegulatorGeneral Description ________
MAX6680MEE+ ,±1°C Fail-Safe Remote/Local Temperature Sensors with SMBus InterfaceFeaturesThe MAX6680/MAX6681 are precise, two-channel digi-♦ Two Alarm Outputs: ALERT and OVERTtal t ..
MB3771. ,Power Supply Monitor
MB3771P ,Power Supply MonitorFUJITSU SEMICONDUCTORDS04-27400-7EDATA SHEETASSP For power supply
MB3771PF ,Power Supply MonitorFUJITSU SEMICONDUCTORDS04-27400-7EDATA SHEETASSP For power supply
MB3771PF. ,Power Supply MonitorapplicationsBIPOLARPower Supply MonitorMB3771nnnn DESCRIPTIONThe Fujitsu MB3771 is designed to moni ..
MB3771PF-G-BND-JNE1 , ASSP For power supply applications BIPOLAR Power Supply Monitor
MB3771PS ,Power Supply MonitorFUJITSU SEMICONDUCTORDS04-27400-7EDATA SHEETASSP For power supply
MAX667CPA-MAX667CSA-MAX667CSA.-MAX667EPA-MAX667ESA-MAX667MJA
+5V/Programmable Low-Dropout Voltage Regulator
_______________General DescriptionThe MAX667 low-dropout, positive, linear voltage regu-
lator supplies up to 250mA of output current. With no
load, it has a typical quiescent current of 20µA. At
200mA of output current, the input/output voltage differ-
ential is typically 150mV. Other features include a low-
voltage detector to indicate power failure, as well as
early-warning and low-dropout detectors to indicate an
imminent loss of output voltage regulation. A shutdown
control disables the output and puts the circuit into a
low quiescent-current mode.
The MAX667 employs Dual Mode™ operation. One
mode uses internally trimmed feedback resistors to pro-
duce +5V. In the other mode, the output may be varied
from +1.3V to +16V by connecting two external resistors.
The MAX667 is a pin-compatible upgrade to the
MAX666 in most applications where the input voltages
are above +3.5V. Choose the MAX667 when high out-
put currents and/or low dropout voltages are desired,
as well as for improved performance at higher
temperatures.
________________________ApplicationsBattery-Powered Devices
Pagers and Radio Control Receivers
Portable Instruments
Solar-Powered Instruments
____________________________Features350mV Max Dropout at 200mA250mA Output CurrentNormal Mode: 20µA Typ Quiescent Current
Shutdown Mode: 0.2µA Typ Quiescent CurrentLow-Battery DetectorFixed +5V (Min Component Count) or
Adjustable Output+3.5V to +16.5V InputDropout Detector Output10µF Output Capacitor
______________Ordering Information
MAX667
+5V/Programmable Low-Dropout
Voltage Regulator
________________________________________________________________Maxim Integrated Products1
__________________Pin Configuration__________Typical Operating Circuit
Call toll free 1-800-998-8800 for free samples or literature.19-3894; Rev 3; 10/94
MAX667* Contact factory for dice specifications.
TM Dual Mode is a trademark of Maxim Integrated Products.
MAX667
+5V/Programmable Low-Dropout
Voltage Regulator_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGSStresses 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.
Input Supply Voltage...........................................................+18V
Output Short Circuited to Ground.........................................1sec
LBO Output Sink Current....................................................50mA
LBO Output Voltage...............................................GND to VOUT
SHDN Input Voltage....................................-0.3V to (VIN+ 0.3V)
Input Voltages LBI, SET................................-0.3V to (VIN- 1.0V)
Continuous Power Dissipation
Plastic DIP (derate 9.09mW/°C above +70°C)............727mW
SO (derate 5.88mW/°C above +70°C).........................471mW
CERDIP (derate 8.00mW/°C above +70°C).................640mW
Operating Temperature Ranges
MAX667C_A........................................................0°C to +70°C
MAX667E_A.....................................................-40°C to +85°C
MAX667MJA..................................................-55°C to +125°C
Storage Temperature Range.............................-65°C to +160°C
Lead Temperature (soldering, 10sec).............................+300°C
Note 1:Dropout Voltage is VIN-VOUTwhen VOUTfalls to 0.1V below its value at VIN= VOUT+ 2V.
Note 2:Short-Circuit Current is pulse tested to maintain junction temperature. Short-circuit duration is limited by package dissipation.
ELECTRICAL CHARACTERISTICS(GND = 0V, VIN= +9V, VOUT = +5V, C1 = 10mF, unless otherwise noted.)
MAX667
+5V/Programmable Low-Dropout
Voltage Regulator
_______________________________________________________________________________________3DROPOUT VOLTAGE
vs. LOAD CURRENT
MAX667-Fg TOC 1
LOAD CURRENT (mA)
DROPOUT VOLTAGE (mV)
QUIESCENT CURRENT
vs. LOAD CURRENTQUIESCENT CURRENT (
10,000
100,000
MAX667-Fg TOC 2
LOAD CURRENT (mA)100050150250
MAX667-Fg TOC 3
DD OUTPUT CURRENT
vs. INPUT-OUTPUT DIFFERENCE
DD OUTPUT CURRENT (
INPUT-OUTPUT DIFFERENCE (mV)
__________________________________________Typical Operating Characteristics
_____________________Pin Description_______________Detailed DescriptionFigure 1 shows a micropower bandgap reference, an
error amplifier, a PNP pass transistor, and two com-
parators as the main elements of the MAX667. One
comparator, C1, selects the fixed 5V or adjustable
operation with an external voltage divider. The other
comparator, C2, is a low-battery detector.
The bandgap reference, which is trimmed to 1.22V,
connects internally to one input of the error amplifier,
A1. The feedback signal from the regulator output sup-
plies the other input of A1 from either an on-chip volt-
age divider or two external resistors. When SET is
grounded, the internal divider provides the error ampli-
fier feedback signal for a fixed 5V output. When SET is
more than 50mV above ground, the error amplifier’s
input switches directly to SET while an external resistor
divider from OUT determines the output voltage.
A second comparator, C2, compares the LBI input to
the internal reference voltage. LBO is an open-drain
FET connected to GND. The low-battery threshold can
also be set with a voltage divider at LBI. In addition, the
MAX667 has a shutdown input (SHDN) that disables
the load and the device while reducing quiescent cur-
rent when it is pulled high.
+5V OutputFigure 2 shows the connection for a fixed 5V output.
The SET input is grounded, and no external resistors
are required. Figure 3 shows adjustable output opera-
tion. R1 and R2 set the output voltage. SHDN should be
grounded if not used.
(TA= +25°C, unless otherwise noted.)
MAX667
+5V/Programmable Low-Dropout
Voltage Regulator_______________________________________________________________________________________Figure 2. Fixed +5V Regulator
Figure 3. Adjustable Output and Low-Battery Detector
Output-Voltage SelectionIf SET is connected to a resistive voltage divider (Figure
3), the output voltage is set by the equation:
VOUT= VSETx(R1 + R2) / R1,
where VSET= 1.22V
To simplify resistor selection:
R2 = R1 x (VOUT / VSET- 1)
Since the input bias current at SET has a maximum
value of 10nA, relatively large values can be used for
R1 and R2 with no loss of accuracy. 1MΩis a typical
value for R1. The VSETtolerance is less than ±25mV.
This allows the output to be preset without trim pots,
using only fixed resistors in most cases. However,
when resistor values greater than 1MΩare used, pay
special attention to printed circuit board leakage that
can introduce error at the SET input.
Shutdown (Standby) ModeSHDN puts the device into standby mode to conserve
power. When this pin is held low, the IC operates nor-
mally. If it is driven above 1.5V, the chip shuts down.
Quiescent current of the MAX667 is then reduced to
less than 1µA, and OUT turns off.
Note that the voltage for SHDN must never be more
than 0.3V higher than VIN.
Low-Battery FunctionThe MAX667 contains circuitry for low-battery detec-
tion. If the voltage at LBI falls below the regulator’s
internal reference (1.22V), LBO, an open-drain output,
sinks current to GND. The threshold can be set to any
level above the reference voltage by connecting a
resistive divider to LBI based on the equation:
R3 = R4 x (VBATT / VLBI- 1)
where VBATTis the desired threshold of the low-battery
detector, and R3 and R4 are the LBI input divider
resistors.
Since LBI input current is no more than 10nA, high val-
ues for R3 and R4 minimize loading. If VOUTis 5V, a
5.5V low-battery threshold can be set using 8.2MΩfor
R3 and 2.4MΩfor R4. When resistor values greater
than 1MΩare used, pay special attention to PC board
leakage that can introduce error at the LBI input.
When the voltage at LBI is below the internal threshold,
LBO sinks current to GND. A pull-up resistor of 10kΩor
more connected to OUT can be used with this pin when
driving CMOS circuits. Any pull-up resistor connected
to LBO should notbe returned to a voltage source
greater than VOUT. When LBI is above the threshold or
the MAX667 is in SHDN mode, the LBO output is off.
Dropout DetectorThe minimum input-output differential, or dropout volt-
age, determines the regulator’s lowest usable input
voltage. In battery-operated systems, this determines
the useful end-of-life battery voltage. The MAX667 fea-
tures very low dropout voltage (see Electrical
Characteristics). In addition, the MAX667 has a dropout
detector output, DD, that changes as the dropout volt-
age approaches its limit. DD is an open collector of a
PNP transistor. The dropout voltage and the dropout
detector both depend on the output current and tem-
perature. When the input voltage is more than 300mV
above the output voltage, the dropout detector will not
conduct. As the differential decreases below 300mV,
the DD source current increases abruptly. This current
signals a warning that regulation is about to be lost.
Connecting a resistor (typically 100kΩ) from DD to
ground develops a voltage that can be monitored by
analog circuits or changed to digital levels by a com-
parator. LBI may be used for this purpose.
__________Applications Information
Output CapacitorAs with all PNP output regulators, an output capacitor
(C1, Figure 2) is required to maintain stability. 10mF is
recommended. To ensure stability, the output-capacitor
ESR must be sufficiently high. Figure 4 shows the mini-
mum required output-capacitor ESR for a given temper-
ature. Alternatively, a resistor may be added in series
with the output capacitor (Figure 5); the sum of the out-
MAX667
+5V/Programmable Low-Dropout
Voltage Regulator
_______________________________________________________________________________________5
MAX667
MAX667put-capacitor ESR and this series resistance should, at
minimum, meet the requirements shown in Figure 4.
An upper limit to the output-capacitor ESR is important
only if step changes to the load are anticipated. Higher
ESR results in higher-amplitude output-voltage tran-
sients when the output current is varied. A Sanyo
OS-CON capacitor, whose ESR is nearly flat over tem-
perature (and is low to begin with), in series with the
appropriate resistor ensures the best load-transient
performance. A less expensive alternative is to use a
tantalum capacitor in series with the resistor.
In most cases, inexpensive aluminum-electrolytic
capacitors work well with the MAX667 over their entire
temperature range, having sufficient ESR to ensure sta-
bility without the need for a series resistor. The ESR of
aluminium electrolytics rises, often dramatically, as
temperature decreases. For surface-mount applica-
tions, certain tantalum capacitors have sufficient ESR;
an example is the TAJB106K016 chip capacitor made
by AVX (phone: (803) 448-9411, fax: (803) 448-1943).
Battery DrainThe MAX667 uses aPNP output transistor. When the
input voltage falls below the desired output voltage, the
+5V/Programmable Low-Dropout
Voltage Regulator_______________________________________________________________________________________
