Rainbow Electronics MAX1673 User Manual
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 408-737-7600 ext. 3468.
________________General Description
The MAX1673 charge-pump inverter provides a lowcost, compact means of generating a regulated negative output from a positive input at up to 125mA. It
requires only three small capacitors, and only two resistors to set its output voltage. The input range is 2V to
5.5V. The regulated output can be set from 0V to -VINin
Skip regulation mode or -1.5V to -VINin Linear (LIN)
regulation mode.
In Skip mode, the MAX1673 regulates by varying its
switching frequency as a function of load current. This
On-Demand™ switching gives the MAX1673 two
advantages: very small capacitors and very low quiescent supply current. At heavy loads, it transfers energy
from the input to the output by switching at up to
350kHz. It switches more slowly at light loads, using
only 35µA quiescent supply current.
In Linear mode, the MAX1673 switches at a constant
350kHz at all loads and regulates by controlling
the current-path resistance. This provides constantfrequency ripple, which is easily filtered for low-noise
applications.
This device also features a 1µA logic-controlled shutdown mode and is available in a standard 8-pin SO
package. For a device that delivers about 10mA and
fits in a smaller package, refer to the MAX868.
________________________Applications
Hard Disk Drives Measurement Instruments
Camcorders Modems
Analog Signal-Processing Digital Cameras
Applications
____________________________Features
♦ Regulated Negative Output Voltage
(up to -1 x VIN)
♦ 125mA Output Current
♦ 35µA Quiescent Supply Current
(Skip-mode regulation)
♦ 350kHz Fixed-Frequency, Low-Noise Output
(Linear-mode regulation)
♦ 2V to 5.5V Input Range
♦ 1µA Logic-Controlled Shutdown
MAX1673
Regulated, 125mA-Output,
Charge-Pump DC-DC Inverter
________________________________________________________________
Maxim Integrated Products
1
FB
OUTSHDN
1
2
87IN
GNDCAP+
CAP-
LIN/SKIP
SO
TOP VIEW
3
4
6
5
MAX1673
Typical Operating Circuit
___________________Pin Configuration
19-1334; Rev 0; 1/98
PART
MAX1673ESA -40°C to +85°C
TEMP. RANGE PIN-PACKAGE
8 SO
_______________Ordering Information
On-Demand™ is a trademark of Maxim Integrated Products.
INPUT 2V TO 5.5V
ON
OFF
IN
SHDN
MAX1673
CAP+
CAP-
LIN/SKIP
FB
OUT
GND
REGULATED
NEGATIVE
OUTPUT
(UP TO -1 x V
UP TO 125mA)
,
IN
MAX1673
Regulated, 125mA-Output,
Charge-Pump DC-DC Inverter
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VIN= V
SHDN
= +5V, CIN= 10µF, C
OUT
= 22µF, C
FLY
= 2.2µF, TA= -40°C to +85°C, unless otherwise noted. Typical values are at
TA= +25°C.) (Note 2)
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..............................................................................-0.3V to +6V
CAP+, FB, LIN/SKIP.....................................-0.3V to (V
IN
+ 0.3V)
SHDN........................................................................-0.3V to +6V
OUT, CAP-................................................................-6V to +0.3V
Continuous Output Current...............................................135mA
Output Short-Circuit Duration to GND (Note 1)....................1sec
Continuous Power Dissipation (T
A
= +70°C)
(derate 5.88mW/°C above +70°C)...............................450mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +160°C
Lead Temperature (soldering, 10sec).............................+300°C
Note 1: Shorting OUT to IN may damage the device and should be avoided.
Output Resistance to Ground
in Shutdown Mode
1 5 Ω
SHDN = GND
Load Regulation ∆V
LDR
0.01
%/mA
0.005
LIN/SKIP = IN
(LIN mode)
LIN/SKIP = GND
(Skip mode)
I
OUT
= 25mA to
125mA, Figure 1
LIN/SKIP = GND
(Skip mode)
LIN/SKIP = IN
(LIN mode)
SHDN = GND
VFB= -25mV, V
OUT
= -3V,
LIN/SKIP = GND (Skip mode)
VFB= -100mV, V
OUT
= -3V,
LIN/SKIP = IN (LIN mode)
LIN/SKIP = GND
(Skip mode)
LIN/SKIP = IN
(LIN mode)
R1 =100kΩ, ±1%,
R2 = 60.4kΩ, ±1%,
I
OUT
= 0mA to
125mA, Figure 1
PARAMETER SYMBOL MIN TYP MAX UNITS
Output Voltage V
OUT
-2.90 -3.02 -3.15
Maximum Output Current I
OUT(MAX)
125 mA
Minimum Output Voltage
-1.5
-2.92 -3.02 -3.12
V
Input Voltage Range V
IN
2.0 5.5
V
2.7 5.5
V
OUT
0
V
Quiescent Current (IINCurrent)
I
Q
8 16
mA
0.035 0.2
Shutdown Current (IINCurrent) I
SHDN
0.1 1 µA
Line Regulation ∆V
LNR
0.01
%/V
1
Open-Loop Output Resistance
(Dropout)
R
O
3.5 10 Ω
CONDITIONS
LIN/SKIP = IN
VIN= 4.5V to 5.5V,
Figure 4,
V
REF
≠ V
IN
LIN/SKIP = GND (Skip mode)
LIN/SKIP = IN (LIN mode)
LIN/SKIP = GND
LIN/SKIP = GND (Skip mode)
VFB= -25mV
MAX1673
Regulated, 125mA-Output,
Charge-Pump DC-DC Inverter
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VIN= V
SHDN
= +5V, CIN= 10µF, C
OUT
= 22µF, C
FLY
= 2.2µF, TA= -40°C to +85°C, unless otherwise noted. Typical values are at
TA= +25°C.) (Note 2)
Note 2: Specifications to -40°C are guaranteed by design, not production tested.
Logic Low Input
(SHDN, LIN/SKIP)
V
IL
0.3 x V
IN
V2V ≤ VIN≤ 5.5V
Logic High Input
(SHDN, LIN/SKIP)
V
IH
0.7 x V
IN
V2V ≤ VIN≤ 5.5V
FB Input Bias Current I
FB
150 600
nA
LIN/SKIP = IN
(LIN mode)
PARAMETER SYMBOL MIN TYP MAX UNITS
FB Threshold V
FBT
-25 0 25 mV
Switching Frequency
(LIN Mode)
ƒ
OSC
250 350 460
kHz
CONDITIONS
Input Bias Current
(SHDN, LIN/SKIP)
LIN/SKIP = GND (Skip mode)
TA= +25°C
1 µA
1 100
LIN/SKIP = GND
(Skip mode)
VFB= -25mV
TA= -40°C to +85°C 205 515
Loading...