19-0191; Rev 2; 12/02
TION KIT
EVALUA
LE
AVAILAB
-5V/-12V/-15V or Adjustable, High-Efficiency,
Low I
Q
Inverting DC-to-DC Controllers
General Description
Features
o
85% Efficiency for 5mA to 1A Load Currents
o
Up to 5W Output Power
o
100µA (max) Supply Current
o
5µA (max) Shutdown Current
o
3V to 16.5V Input Range
o
-5V (MAX774), -12V (MAX775), -15V (MAX776),
or Adjustable Output Voltage
o
Current-Limited PFM Control Scheme
o
300kHz Switching Frequency
MAX774/MAX775/MAX776
The MAX774/MAX775/MAX776 inverting switching
regulators deliver high efficiency over three decades of
load current. A unique current-limited, pulse-
frequency modulated (PFM) control scheme provides
the benefits of pulse-width modulation (high efficiency
with heavy loads), while using less than 100µA of supply
current (vs. 2mA to 10mA for PWM converters). The result
is high efficiency over a wide range of loads.
These ICs also use tiny external components; their high
switching frequency (up to 300kHz) allows for less than
5mm diameter surface-mount magnetics.
The MAX774/MAX775/MAX776 accept input voltages from
3V to 16.5V, and have preset output voltages of
-5V, -12V, and -15V, respectively. Or, the output voltage
can be user-adjusted with two resistors. Maximum
V
IN
- V
OUT
differential voltage is limited only by the break-
down voltage of the chosen external switch transistor.
These inverters use external P-channel MOSFET switches,
allowing them to power loads up to 5W. If less power is
required, use the MAX764/MAX765/MAX766 inverting
switching regulators with on-board MOSFETs.
Ordering Information
PART
MAX774CPA
MAX774CSA
MAX774C/D
MAX774EPA
MAX774ESA
MAX774MJA
TEMP RANGE
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
PIN-PACKAGE
8 Plastic DIP
8 SO
Dice*
8 Plastic DIP
8 SO
8 CERDIP
Applications
LCD-Bias Generators
High-Efficiency DC-to-DC Converters
Battery-Powered Applications
Data Communicators
*Contact
factory for dice specifications.
Ordering Information continued on last page.
Typical Operating Circuit
INPUT
3V TO 16V
V+
Pin Configuration
TOP VIEW
MAX774
ON/OFF
SHDN
CS
EXT
P
OUTPUT
-5V
OUT
FB
SHDN
REF
1
2
3
4
8
GND
EXT
CS
V+
FB
REF
GND
OUT
MAX774
MAX775
MAX776
7
6
5
DIP/SO
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
-5V/-12V/-15V or Adjustable, High-Efficiency,
Low I
Q
Inverting DC-to-DC Controllers
MAX774/MAX775/MAX776
ABSOLUTE MAXIMUM RATINGS
Supply Voltages
V+ to OUT ...........................................................................21V
V+ to GND ..............................................................-0.3V, +17V
OUT to GND ........................................................-0.3V, to -17V
REF, SHDN, FB, CS...................................-0.3V to (V+ + 0.3V)
EXT ...............................................(V
OUT
- 0.3V) to (V+ + 0.3V)
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
CERDIP (derate 8.00mW/°C above +70°C) ..................640mW
Operating Temperature Ranges:
MAX77_C_ _ .........................................................0°C to +70°C
MAX77_E_ _ ......................................................-40°C to +85°C
MAX77_MJA ...................................................-55°C to +125°C
Maximum Junction Temperatures:
MAX77_C_ _/E_ _ ...........................................................+150°C
MAX77_MJA..................................................................+175°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10s) .................................+300°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.
ELECTRICAL CHARACTERISTICS
(V+ = 5V, I
LOAD
= 0mA, C
REF
= 0.1µF, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
V+ Input Voltage Range
SYMBOL
V+
V+ = 16.5V, SHDN
≤
0.4V (operating)
Supply Current
V+ = 10V, SHDN
≥
1.6V (shutdown)
V+ = 16.5V, SHDN
≥
1.6V (shutdown)
FB Trip Point
3V
≤
V+
≤
16.5V
MAX77_C
FB Input Current
I
FB
MAX77_E
MAX77_M
MAX774
Output Voltage
V
OUT
MAX775
MAX776
MAX77_C
Reference Voltage
V
REF
I
REF
= 0µA
MAX77_E
MAX77_M
REF Load Regulation
REF Line Regulation
Output Voltage Line Regulation
(Circuit of Figure 2—
Bootstrapped)
Output Voltage Load Regulation
(Circuit of Figure 2—
Bootstrapped)
0µA
≤
I
REF
≤
100µA
3V
≤
V+
≤
16.5V
MAX774, 4V
≤
V+
≤
15V, I
LOAD
= 0.5A
MAX775, 4V
≤
V+
≤
8V, I
LOAD
= 0.2A
MAX776, 4V
≤
V+
≤
6V, I
LOAD
= 0.1A
MAX774, 0A
≤
I
LOAD
≤
1A, V+ = 5V
MAX775, 0mA
≤
I
LOAD
≤
500mA, V+ = 5V
MAX776, 0mA
≤
I
LOAD
≤
400mA, V+ = 5V
MAX77_C/E
MAX77_M
-4.80
-11.52
-14.40
1.4700
1.4625
1.4550
-5
-12
-15
1.5
1.5
1.5
4
4
40
0.035
0.088
0.137
1.5
1.5
1.0
mV/A
mV/V
-10
2
4
10
±50
±70
±90
-5.20
-12.48
-15.60
1.5300
1.5375
1.5450
10
15
100
mV
µV/V
V
V
nA
mV
CONDITIONS
MIN
3.0
TYP
MAX
16.5
100
5
µA
UNITS
V
2
_______________________________________________________________________________________
-5V/-12V/-15V or Adjustable, High-Efficiency,
Low I
Q
Inverting DC-to-DC Controllers
ELECTRICAL CHARACTERISTICS (continued)
(V+ = 5V, I
LOAD
= 0mA, C
REF
= 0.1µF, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
Efficiency
(Circuit of Figure 2—
Bootstrapped)
SHDN Input Current
SHDN Input Voltage High
SHDN Input Voltage Low
Current-Limit Trip Level
(V+ – CS)
CS Input Current
Switch Maximum On-Time
Switch Minimum Off-Time
EXT Rise Time
EXT Fall Time
t
ON
(max)
t
OFF
(max)
V+ = 12V
V+ = 12V
C
EXT
= 1nF, V+ = 12V
C
EXT
= 1nF, V+ = 12V
12
1.8
16
2.3
50
50
V
IH
V
IL
V
CS
SYMBOL
CONDITIONS
MAX774, V+ = 5V, I
LOAD
= 1A
MAX775, V+ = 5V, I
LOAD
= 500mA
MAX776, V+ = 5V, I
LOAD
= 400mA
V+ = 16.5V, SHDN = 0V or V+
3V
≤
V+
≤
16.5V
3V
≤
V+
≤
16.5V
3V
≤
V+
≤
16.5V
MAX77_C/E
MAX77_M
MAX77_C/E
MAX77_M
1.6
0.4
0.3
240
260
±1
20
2.8
MIN
TYP
82
88
87
±1
MAX
UNITS
%
µA
V
V
mV
µA
µs
µs
ns
ns
MAX774/MAX775/MAX776
180
160
210
210
_______________________________________________________________________________________
3
-5V/-12V/-15V or Adjustable, High-Efficiency,
Low I
Q
Inverting DC-to-DC Controllers
MAX774/MAX775/MAX776
__________________________________________Typical Operating Characteristics
(T
A
= +25°C, unless otherwise noted.)
MAX774
EFFICIENCY vs. LOAD CURRENT
V
OUT
= -5V (BOOTSTRAPPED)
MAX1774/5/6-01a
MAX774
EFFICIENCY vs. LOAD CURRENT
V
OUT
= -5V (NONBOOTSTRAPPED)
MA774/5/6--1b
MAX774
EFFICIENCY vs. TEMPERATURE
I
LOAD
= 100mA
80
EFFICIENCY (%)
MAX774/5/6-2
90
V
IN
= 5V
80
EFFICIENCY (%)
V
IN
= 3V
V
IN
= 15V
70
90
V
IN
= 5V
80
EFFICIENCY (%)
V
IN
= 4V
70
V
IN
= 15V
90
I
LOAD
= 600mA
I
LOAD
= 1A
70
60
60
60
V
IN
= 5V
BOOTSTRAPPED
50
1
10
100
1000
LOAD CURRENT (mA)
50
1
10
100
1000
LOAD CURRENT (mA)
50
-40
-20
0
20
40
60
80
100
TEMPERATURE (°C)
MAX776
EFFICIENCY vs. LOAD CURRENT
V
OUT
= -15V (BOOTSTRAPPED)
MA774/5/6-1c
MAX776
EFFICIENCY vs. LOAD CURRENT
V
OUT
= -15V (NONBOOTSTRAPPED)
MA774/5/6-1d
MAX775
EFFICIENCY vs. OUTPUT CURRENT
V
OUT
= -12V (BOOTSTRAPPED)
MA774/5/6--1
e
90
V
IN
= 6V
90
90
80
EFFICIENCY (%)
V
IN
= 5V
EFFICIENCY (%)
V
IN
= 4V
V
IN
= 3V
80
V
IN
= 15V
70
V
IN
= 6V
V
IN
= 4V
70
EFFICIENCY (%)
V
IN
= 5V
80
V
IN
= 4V
70
V
IN
= 5V
V
IN
= 8V
60
60
60
50
1
10
100
1000
LOAD CURRENT (mA)
50
1
10
100
1000
LOAD CURRENT (mA)
50
1
10
100
1000
OUTPUT CURRENT (mA)
MAX774/MAX775/MAX776
EFFICIENCY vs. LOAD CURRENT
V
OUT
= -24V (NONBOOTSTRAPPED)
MA774/5/6--1f
MAX774/MAX775/MAX776
EFFICIENCY vs. LOAD CURRENT
V
OUT
= -24V OUTPUT (ZENER CONNECTION)
MA774/5/6--1g
MAX774
EFFICIENCY vs. INPUT VOLTAGE
V
OUT
= -5V AT 100mA
86
EFFICIENCY (%)
84
82
80
NONBOOTSTRAPPED
78
76
V
OUT
= -5V AT 100mA
MAX774/5/6-3
90
V
IN
= 6V
80
EFFICIENCY (%)
V
IN
= 4V
70
V
IN
= 5V
90
V
IN
= 6V
80
EFFICIENCY (%)
V
IN
= 4V
70
V
IN
= 5V
88
BOOTSTRAPPED
60
60
50
1
10
100
1000
LOAD CURRENT (mA)
50
1
10
100
1000
LOAD CURRENT (mA)
74
2
4
6
8
10
12
14
16
INPUT VOLTAGE (V)
4
_______________________________________________________________________________________
-5V/-12V/-15V or Adjustable, High-Efficiency,
Low I
Q
Inverting DC-to-DC Controllers
_____________________________Typical Operating Characteristics (continued)
(T
A
= +25°C, unless otherwise noted.)
STARTUP VOLTAGE
vs. LOAD CURRENT (BOOTSTRAPPED)
MA744/5/6-14
MAX774/MAX775/MAX776
STARTUP VOLTAGE
vs. LOAD CURRENT (NONBOOTSTRAPPED)
MA744/5/6-15
MAX774
MAXIMUM LOAD vs. INPUT VOLTAGE
V
OUT
= -5V
2000
LOAD CURRENT (mA)
1800
BOOTSTRAPPED
1600
1400
1200
NONBOOTSTRAPPED
1000
800
MAX774/5/6-16
5.0
V
OUT
= -15V
4.5
START-UP VOLTAGE (V)
V
OUT
= -12V
5.0
V
OUT
= -12V
4.5
START-UP VOLTAGE (V)
V
OUT
= -15V
2200
4.0
4.0
V
OUT
= -24V
3.5
V
OUT
= -5V
3.0
3.5
3.0
V
OUT
= -5V
2.5
1
10
100
1000
LOAD CURRENT (mA)
2.5
0.1
1
10
100
1000
LOAD CURRENT (mA)
2
4
6
8
10
12
14
16
INPUT VOLTAGE (V)
EXT RISE AND FALL TIMES
vs. TEMPERATURE
MAX774/5/6-9
EXT RISE AND FALL TIMES
vs. TEMPERATURE
C
EXT
= 5nF
MAX774/5/6-10
SWITCH ON-TIME vs. TEMPERATURE
V+ = 5V
MAX761-13
130
120
110
100
t
RISE &
t
FALL
(ns)
90
80
70
60
50
40
30
20
C
EXT
= 1nF
500
450
400
t
RISE &
t
FALL
(ns)
17
5V RISE
5V FALL
12V RISE
12V FALL
5V RISE
ton (µs)
5V FALL
12V RISE
12V FALL
15
-60 -40 -20
0
20
40 60
80 100 120 140
-60
0
60
120
TEMPERATURE (°C)
TEMPERATURE (°C)
350
300
250
200
150
100
50
16
-60 -40 -20
0
20
40 60
80 100 120 140
TEMPERATURE (°C)
SWITCH OFF-TIME vs. TEMPERATURE
MAX761-13
SWITCH ON-TIME/OFF-TIME RATIO
7.8
7.6
t
ON
/t
OFF
RATIO (µs/µs)
7.4
I
CC
(µA)
7.2
7.0
6.8
6.6
6.4
6.2
0.5
V+ = 5V
MAX774/5/6-6
SHUTDOWN CURRENT
vs. TEMPERATURE
3.5
3.0
2.5
2.0
1.5
1.0
V+ = 4V
0
V+ = 8V
V+ = 15V
MAX774/5/6-7
2.5
V+ = 5V
8.0
4.0
t
OFF
(µs)
2.0
1.5
-60
0
60
120
TEMPERATURE (°C)
6.0
-60 -40 -20
0
20
40 60
80 100 120 140
TEMPERATURE (°C)
-60 -40 -20
0
20
40 60
80 100 120 140
TEMPERATURE (°C)
_______________________________________________________________________________________
5
嵌入式系统
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
