MAX638AESA ,+5V/Adjustable CMOS Step-down Switching RegulatorELECTRICAL CHARACTERISTICS
(+Vs = +12V, TA = +25°C, unless otherwise noted.)
PARAMETER SYMBOL ..
MAX638AESA ,+5V/Adjustable CMOS Step-down Switching Regulatorfeatures such as
logic-level shutdown, adjustable oscillator frequency,
and external MOSFET drive ..
MAX638AESA ,+5V/Adjustable CMOS Step-down Switching RegulatorELECTRICAL CHARACTERISTICS
(+Vs = +12V, TA = +25°C, unless otherwise noted.)
PARAMETER SYMBOL ..
MAX638AESA+ ,5V Adjustable, CMOS, Step-Down Switching RegulatorApplications MAX638AEPA -4CY'C to +85°C 8 Plastic DIP
Efficient DC-DC Step-Down Regulation MAX638A ..
MAX638BCJA ,5V Adjustable, CMOS, Step-Down Switching Regulatorapplications require only a small, low-cost induc-
tor, an output filter capacitor, and a catch di ..
MAX6390XS26D7-T ,SC70, Single/Dual Low-Voltage, Low-Power レP Reset CircuitsELECTRICAL CHARACTERISTICS(V = full range, T = -40°C to +125°C, unless otherwise specified. Typical ..
MB2374BB ,Dual octal D-type flip-flop; positive-edge trigger (3-State)
MB2374BB ,Dual octal D-type flip-flop; positive-edge trigger (3-State)
MB2374BB ,Dual octal D-type flip-flop; positive-edge trigger (3-State)
MB2543BB ,Dual octal latched transceivers with dual enable 3-State
MB2543BB ,Dual octal latched transceivers with dual enable 3-State
MB2652BB ,Dual octal transceiver/registers, non-inverting 3-State
MAX638ACPA-MAX638ACSA-MAX638AEPA-MAX638AESA
+5V/Adjustable CMOS Step-down Switching Regulator
79-0919, Rev 1; T/96
2AylLaiClheAy)ll
+SWadliiusitalblle CMO$ Step-down
General Description
The MAX638 step-down switching regulator is designed
for minimum component, low power, DC-DC conversion.
Typical applications require only a small, Iow-cost induc-
tor, an output filter capacitor, and a catch diode. Low
battery detection circuitry is included on chip.
Though most simply used as a fixed +5V output regulator,
the MAX638 can be set for other voltages by adding 2
resistors.
Maxim manufactures a broad line of step-up, step-down,
and inverting DC-DC converters, with features such as
logic-level shutdown, adjustable oscillator frequency,
and external MOSFET drive.
Switching Regulator
Fea tures
. Fixed +5V Output
t Adjustable Output with 2 Resistors
t Low Operating Current
0 85% Typ Efficiency
t 8-Pin Plastic DIP and Narrow so Packages
t 3 External Components
t Low Battery
Detector
Ordering Information
PART TEMP. RANGE PIN-PACKAGE
MAX638ACPA 0°C to +70°C 8 Plastic DIP
MAX638ACSA 0°C to +70°C 8 Narrow SO
. " MAX638AC/D 0°C to +70°C Dice
Applications MAX638AEPA -40''C to +85°C 8 Plastic DIP
Efficient DC-DC Step-Down Regulation MAX638AESA -40oC to +85°C 8 Narrow so
Linear Voltage Regulator Replacement MAX638AMJA -55''C to +125''C 8 CERDIP
+12V to +5V Conversion
Battery Life Extension
Portable Instruments
Pin Configuration Typical Operating Circuit
Top View
+6V TO 16.5V
+Vs 5 +5V
. V LX >—>
vow E E COMP
LU) E MAXIM El VFB Mags"
uy [E MAX638 E Ws
GND E E LX VOW 1 ,
LBI GND VFB ,:
DIP/SO l 3 y l7 T
+5V OUTPUT STEP-DOWN REGULATOR
MAXIM Maxim Integrated Products 1
& the latest literature: http://www. maxim-ic.com, .
For small orders, phone 1-800-835-8769.
8’89wi
MAX638
+SWadliusitalblle CMOS §itep-Down
Switching [Regulator
ABSOLUTE MAXIMUM RATINGS
Supply Voltage +Vs ............................................................. A181/ Storage Temperature ......................................... -65°C to +160°C
Output Voltage +Lx ..r..r......rr...mw'w..mwmm.r.'rm._._rrrr...'F'"'''''''"'''P'. x18V Lead Temperature (Soldering, 10 sec.) ........................... +300°C
Output Voltage LBO ............................... Power Dissipation
Input Voltage LBO, LBI, VFB, COMP.. Plastic DIP (derate 8.33mW/°C) ._...9..F...t.lF.FF.._ 625mW
LX Output Current ............................... Small Outline (aerate 6mW/°C) .................... ....450mW
LBO Output Current ..r..t......mr...mwm...r....'''"rrmm.rrF''.''.'".'"''''''.'. 50mA CERDIP (derate 8mW/°C above +50C) ........................ 800mW
Operating Temperature
MAX638AC ......................................................... 0°C to +70°C
MAX638AE..... ....-40°C to +85°C
MAX638AM .................................................... -55°C to +125°C
Stresses beyond those listed under "Absolute Mammum Ratings" may cause permanent damage to the device, These are stress ratings only. and functional
operation of the device at these or any other condtions beyond those indicated m the operational sections of the specifications 15 not implied Exposure tc
absolute maxrmum rating conditions for extended periods may affect dewce reliability.
ELECTRICAL CHARACTERISTICS
(+Vs = +12V, TA = +25C, unless otherwise noted.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Over Temperature
Supply VoItage +Vs VOUT = +5V 5 16.5 V
Adjustable mode 2.2 16.5
TA = 4-250 135
Supply Current ls Over Temperature 180 600 “A
TA = +25°C 1.28 1.31 1.34
Reference Voltage (Internal) Over Temperature 1.24 1.38 V
No Load, VFB = GND,
VOUT Voltage (Note 1) Over Temperature 4.75 5.0 5.25 V
Efficiency 85 %
Line Regulation (Note 1) +10V < +Vs < +15V 0.2 % VOUT
Load Regulation (Note 1) POUT = OmW to 150mW 0.2 % VOUT
Oscillator Frequency fo 65 kHz
Oscillator Duty Cycle 50 %
Lx ON Resistance RON Ix = 100mA 6 12 Q
V5 = OV
Lx Leakage Current IXL TA = +250 0.01 1.0 WA
Over Temperature 30
VFB Input Bias Current IFB 0.01 10 nA
Low Battery Input Threshold VLBI 1.31 V
Low Battery Input
Bias Current ILB; 0.01 10 nA
V2 = +0.4V. V3 = +1.1V
Low Battery Output Current ILBo TA = +25°C 1.0 mA
Over Temperature 05
Low Battery Output A _
Leakage Current 'LBOL V2 - +vs, V3 _ +1.4v 0.01 3.0 pA
Note 1: Guaranteed by correlation with DC pulse measurements.
2 M/JXI/VI
