OMO ElectronicOMO Electronic
Expand menu
Hello, Sign inMy Account
0 Cart

MAX688CUA+

P1-P3P4-P6P7-P9P10-P12
_______________General Description
The MAX687/MAX688/MAX689 low-dropout linear regula-
tors operate with an input-to-output voltage differential lim-
ited only by an external PNP transistor. Outputs are fixed
at 3.3V (MAX687/MAX688) or 3.0V (MAX689). The only
external components required are a PNP pass transistor
and output, compensation, and bypass capacitors. Base
drive to the external transistor is at least 10mA, permitting
output currents to exceed 1A when using high-gain tran-
sistors (β > 100). Output current limiting is implemented
by limiting the external transistor’s base current. Output
voltage monitoring and shutdown functions are included.
The 3.3V MAX687 automatically shuts down whenever
the output voltage drops below 2.96V. An internal
power-fail comparator also monitors the output and pro-
vides an early warning of low output voltage before the
device shuts down. When shut down, the output is
latched off until the ON input is pulsed. Turning off the
power supply in this way prevents battery damage due
to excessive discharge or cell-reversal. Typical applica-
tions include portable telephones and other battery-pow-
ered equipment where the power supply must be
disabled when the battery voltage is low.
The MAX688 and MAX689 do not have an automatic
shutdown function, and are identical except for their
output voltages. Each device has an active-low shut-
down-control input, used to turn its output on or off at
any time. As SHDN falls, the device enters a standby
mode before fully shutting down. When in standby, the
reference and comparators are fully operational, per-
mitting the transition from normal mode to standby
mode to occur at a precise voltage level on SHDN.
________________________Applications
High-Efficiency Linear Regulator
Battery-Powered Devices
Portable Instruments
Portable Telephones
Power Supply or Backup Supply for Memory
____________________________Features
♦ Fixed Outputs:
3.3V (MAX687/MAX688)
3.0V (MAX689)
♦ Directly Drives External PNP Transistor
♦ 10mA Min Base-Current Drive for >1A Output
♦ Low Dropout Voltage:
100mV Dropout at 650mA Output (FZT749)
40mV Dropout at 200mA Output (FZT749)
0.8V Dropout at 4A Output
♦ Power-Fail Output Monitors the Output Voltage
♦ Automatic, Latched Shutdown when Output Falls Out
of Regulation (MAX687)
♦ Precision Threshold Shutdown Control
(MAX688/MAX689)
♦ Low Supply Current:
150µA Operating
<1µA Shutdown
♦ 2.7V to 11.0V Supply Range
♦ 8-Pin DIP/SO/µMAX Packages
♦ <2mV Line Transient with 3.4V to 3.6V Input
♦ Output Accuracy <±2%
______________Ordering Information
Ordering Information continued at end of data sheet.
MAX687/MAX688/MAX689
High-Accuracy, Low-Dropout
Linear Regulators
________________________________________________________________
Maxim Integrated Products
1
MAX687
Q1
FZT749
R
B
12Ω
BASE
GND
C1
2.2µF
IN
BLIM
OUT
POWER-FAIL
OUTPUT
3.3V @ 500mA
PFO
CC
+3.5V to +5V INPUT
ON
C3
10nF
ON
GND
C2
68µF
__________Typical Operating Circuit
1
2
3
4
8
7
6
5
CC
BASE
BLIM
OUT
GND
PFO
(ON) SHDN
IN
MAX687
MAX688
MAX689
DIP/SO/µMAX
TOP VIEW
( ) ARE FOR MAX687
__________________Pin Configuration
Call toll free 1-800-998-8800 for free samples or literature.
19-0329; Rev 0; 12/94
PART
MAX687CPA
MAX687CSA
MAX687CUA 0°C to +70°C
0°C to +70°C
0°C to +70°C
TEMP. RANGE PIN-PACKAGE
8 Plastic DIP
8 SO
8 µMAX
EVALUATION KIT MANUAL
FOLLOWS DATA SHEET
MAX687EPA
MAX687ESA -40°C to +85°C
-40°C to +85°C 8 Plastic DIP
8 SO
MAX687/MAX688/MAX689
High-Accuracy, Low-Dropout
Linear Regulators
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
IN
= 3.8V, SHDN = V
IN
(MAX688/MAX689), R
B
= 0Ω, C1 = 2.2µF, C2 = 10µF, C3 = 10nF, T
A
= T
MIN
to T
MAX
, unless otherwise
noted. Typical values are at T
A
= +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.
Input Supply Voltage IN to GND............................................12V
Terminal Voltages to GND
PFO
(MAX687)........................................-0.3V to V
OUT
+ 0.3V
PFO
(MAX688/MAX689) ......................................-0.3V to 12V
All Remaining Pins .....................................-0.3V to V
IN
+ 0.3V
PFO
Sink Current ...............................................................10mA
PFO
Source Current (MAX687)...........................................10mA
Continuous Power Dissipation (T
A
= +70°C)
Plastic DIP (derate 9.09mW/°C above +70°C) ............727mW
SO (derate 5.88mW/°C above +70°C).........................471mW
µMAX (derate 4.1mW/°C above +70°C) ......................330mW
Operating Temperature Ranges
MAX68_C_A .......................................................0°C to +70°C
MAX68_E_A ....................................................-40°C to +85°C
Storage Temperature Range.............................-65°C to +165°C
Lead Temperature (soldering, 10sec).............................+300°C
MAX687/MAX688
(Note 1)
V
BASE
= V
IN
- 1V
PNP = FZT749, I
LOAD
= 100mA (Note 4)
V
IN
= 3.8V,
PNP = FZT749,
no load
(Note 3)
1µA ≤ I
BASE
≤ 10mA
R
B
is connected from BASE to BLIM (Ω),
R
B
= 0Ω to 100Ω
CONDITIONS
µF10C2Load Capacitance
%2Start-Up Overshoot
µs300Start-Up Time
mA
70 100 130
R
B
+ 5Ω R
B
+ 5Ω R
B
+ 5Ω
Base-Current Limit
V
3.2 3.3 3.4
V
OUT
Output Voltage
V2.7 11.0V
IN
Supply Voltage
mA10 20 40I
BASE
BASE Sink Current
< 0.02 1
11 25
µA
150 250
I
GND
Supply Current
3.13 3.3 3.47
mV40V
IN
- V
OUT
Dropout Voltage (Note 2)
mV/V
0.4 1.4
Line Regulation
mV45 60Load Regulation
UNITSMIN TYP MAXSYMBOLPARAMETER
V
IN
= 3.8V, I
BASE
= 1mA
3.8V ≤ V
IN
≤ 11.0V,
1µA ≤ I
BASE
≤ 10mA
PNP = FZT749, I
LOAD
= 200mA, C2 = 20µF
3.8V ≤ V
IN
≤ 11.0V,
I
BASE
= 1mA
MAX687/MAX688
MAX689
2.9 3.0 3.1
2.85 3.0 3.15
V
IN
= 3.5V, I
BASE
= 1mA
3.5V ≤ V
IN
≤ 11.0V,
1µA ≤ I
BASE
≤ 10mA
MAX689
3.5V ≤ V
IN
≤ 11.0V,
I
BASE
= 1mA
0.4 1.4
On
Standby,
MAX688/MAX689
Shutdown
LINEAR REGULATOR
MAX687/MAX688/MAX689
High-Accuracy, Low-Dropout
Linear Regulators
_______________________________________________________________________________________ 3
Note 1: Minimum V
IN
for regulated V
OUT
depends on the characteristics of the external PNP transistor, and on the load. The refer-
ence and comparators are functional down to the minimum voltage specified, but the output may not be in regulation.
Note 2: Dropout voltage is defined as V
IN
- V
OUT
when V
OUT
is 50mV below its value at V
IN
= V
NOM
+ 1V.
Note 3: The start-up time specification is the time taken from ON or SHDN
rising to BASE sinking current. V
OUT
rise time is longer
and is a function of load capacitance, C2, and load resistance, R
L
.
Note 4: Minimum load capacitance is a function of R
L
. Minimum C2 = 10µF for loads up to 100mA and 1µF/10mA for higher loads.
ESR of C2 should be no larger than 1/100 of R
L
. Guaranteed by design.
Note 5: The nominal output voltage, V
NOM
, is defined under the default conditions of testing: V
IN
= 3.8V, I
BASE
= 1mA, T
A
= T
MIN
to T
MAX
.
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= 3.8V, SHDN = V
IN
(MAX688/MAX689), R
B
= 0Ω, C1 = 2.2µF, C2 = 10µF, C3 = 10nF, T
A
= T
MIN
to T
MAX
, unless otherwise
noted. Typical values are at T
A
= +25°C.)
Falling V
OUT
, comparators monitor V
OUT
Glitch immunity
Rising SHDN, standby→on
Shutdown
Standby
Falling V
OUT
, comparators monitor V
OUT
On, SHDN falling
Output turns on
CONDITIONS
µs100PFO, SHDN Transient Rejection
mV70SHDN Hysteresis
0.2V
SSD
1.0 1.2V
SSY
V
1.25V
SON
SHDN Threshold Voltages
mV110 170
V
NOM
-
V
PFT
PFO Threshold Voltage Below
V
NOM
(Note 5)
mV7PFO Hysteresis
V2.96V
SD
Shutdown Threshold Voltage
V
1.0V
IH
ON Threshold Voltage
UNITSMIN TYP MAXSYMBOLPARAMETER
I
SOURCE
= 50µA, part on, V
IN
= 2.7V VV
OUT
- 0.3V
OH
PFO Output Voltage High
I
SINK
= 1.2mA, V
IN
= 2.7V V0.06 0.3V
OL
PFO Output Voltage Low
Output remains off 0.2V
IL
nA0.2 100ON Input Leakage Current
Falling V
OUT
, com-
parators monitor V
OUT
V
3.07 3.13 3.19
V
PFT
PFO Threshold Voltage
MAX688
MAX689 2.77 2.85 2.89
V
SHDN
= 1.23V nA-25 25SHDN Input Current
10Hz ≤ f ≤ 10kHz, I
LOAD
= 200mA
V
PFO
= 11V, V
SHDN
> 1.25V
I
SINK
= 1.2mA, V
IN
= 2.7V
µA1
66
e
n
Output Noise Voltage
PFO Off Leakage Current
V0.06 0.3V
OL
PFO Output Voltage Low
10Hz ≤ f ≤ 1MHz, I
LOAD
= 200mA
µV
RMS
105
Falling V
OUT
, comparators monitor V
OUT
mV20 70V
PFT
- V
SD
Shutdown Threshold Voltage
Below V
PFT
mV7PFO Hysteresis
MAX688/MAX689: SHDN, PFO
MAX687: ON, PFO, SHDN
P1-P3P4-P6P7-P9P10-P12

MAX688CUA+

Mfr. #:
Buy MAX688CUA+
Manufacturer:
Maxim Integrated
Description:
LDO Voltage Regulators High-Accuracy LDO
Lifecycle:
New from this manufacturer.
Delivery:
DHL FedEx Ups TNT EMS
Payment:
T/T Paypal Visa MoneyGram Western Union

Products related to this Datasheet