AMS AMS494 Internal regulator provides a stable 5v reference supply Datasheet

AMS494
Features
PIN CONFIGURATION
• Internal regulator provides a stable 5V reference supply
trimmed to 5%
• Uncommitted output TR for 200mA sink or source
current
• Output control for push-pull or single-ended operation
• Variable duty cycle by dead time control (pin 4) Complete
PWM control circuit
• On-chip oscillator with master or slave operation
• Internal circuit prohibits double pulse at either output
Description
The AMS494 is used for the control circuit of the PWM
switching regulator. The AMS494 consists of 5V reference
voltage circuit, two error amplifiers, flip flop, an output control circuit, a PWM comparator, a dead time comparator and
an oscillator. This device can be operated in the switching
frequency of 1 KHz to 300 KHz.
1B
1
16
1C
2B
2
15
2C
3B
3
14
3C
4B
4
13
4C
5B
5
12
5C
6B
6
11
6C
7B
7
10
7C
E
8
9
(Top View)
Internal Block Diagram
1
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AMS494
Absolute Maximum Ratings
Parameter
Supply Voltage
Collector Supply Voltage
Output Current
Symbol
Value
Unit
VCC
42
V
VC
42
V
IO
250
mA
Amplifier Input Voltage
VIN
VCC + 0.3
V
Power Dissipation (TA = 25°C)
PD
Operating Temperature Range
TOPR
0 ~ +70
°C
Storage Temperature Range
TSTG
-65 ~ + 150
°C
1 (AMS494CN)
0.9 (AMS494CD)
2
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AMS494
Electrical Characteristics
(VCC = 20V, f = 10KHz, TA = 0°C to + 70°C, unless otherwise specified)
Parameter
Symbol
Conditions
Min.
Typ.
Max.
Unit
4.75
5.0
5.25
V
-
2.0
25
mV
TA = 0°C to 70°C
-
0.01
0.03
%/°C
IREF = 1mA to 10mA
-
1.0
15
mV
10
35
50
mA
REFERENCE SECTION
Reference Output Voltage
VREF
∆VREF
Line Regulation
Temperature Coefficient of VREF
∆VREF/∆T
∆VREF
Load Regulation
Short-Circuit Output Currnet
ISC
IREF = 1mA
VCC = 7V to 40V
VREF = 0V
OSCILLATOR SECTION
Oscillation Frequency
Frequency Change with Temperature
f
CT = 0.01µF, RT = 12KΩ
-
10
-
KHz
∆f/∆T
CT = 0.01µF, RT = 12KΩ
-
-
2
%
IBIAS
VCC = 15V, 0V≤V4≤5.25V
-
-2.0
-10
µA
45
-
-
%
Zero Duty Cycle
-
3.0
3.3
Max. Duty Cycle
0
-
-
DEAD TIME CONTROL SECTION
Input Bias Current
Maximum Duty Cycle
D(MAX)
Input Threshold Voltage
VITH
VCC = 15V, V4 = 0V
O.C Pin = VREF
V
ERROR AMP SECTION
Input Offset Voltage
VIO
V3 = 2.5V
-
2.0
10
mV
Input Offset Current
IIO
V3 = 2.5V
-
25
250
mA
Input Bias Current
IBIAS
V3 = 2.5V
-
0.2
1.0
µA
Common Mode Input Voltage
VCM
7V ≤ VCC ≤ 40V
-0.3
-
VCC
V
Open-Loop Voltage Gain
GVO
0.5V ≤ V3 ≤3 .5V
70
95
-
dB
Unit-Gain Bandwidth
BW
-
650
-
KHz
-
PWM COMPARATOR SECTION
Input Threshold Voltage
VITH
Zero Duty Cycle
Input Sink Currnet
ISINK
V3=0.7V
-
4
4.5
V
-0.3
-0.7
-
mV
OUTPUT SECTION
Output Saturation Voltage
Common Emitter
VCE(SAT)
VE = 0, IC = 200mA
-
1.1
1.3
Common Collector
VCC(SAT)
VC = 15V, IE = -200mA
-
1.5
2.5
Collector Off-State Currnet
IC(OFF)
VCC = 40V, VCE = 40V
-
2
100
Emitter Off-State Current
IE(OFF)
VCC = VC = 40V, VE = 0
-
-
-100
ICC
Pin 6 = VREF, VCC = 15V
-
6
10
mA
-
V
µA
TOTAL DEVICE
Supply Current
OUTPUT SWITCHING CHARACTERISTIC
Rise Time
tR
-
-
-
-
Common Emitter
-
-
-
100
200
Common Collector
-
-
-
100
200
Fall Time
tF
-
-
-
-
Common Emitter
-
-
-
25
100
Common Collector
-
-
-
40
100
3
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ns
AMS494
Typical Application
Pulse Width Modulated Step-down Converter
AMS494
4
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AMS494
Mechanical Dimensions
Package
16-DIP
#9
7.62
0.300
2.54
0.100
3.25 ±0.20
0.128 ±0.008
0.38
0.014 MIN
3.30 ±0.30
0.130 ±0.012
5.08
MAX
0.200
+0.10
0~15°
0.25 –0.05
+0.004
0.010 –0.002
5
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1.50 ±0.10
0.059 ±0.004
#8
19.40 ±0.20
0.764 ±0.008
#16
19.80
MAX
0.780
#1
0.46 ±0.10
0.018 ±0.004
(
0.81
)
0.032
6.40 ±0.20
0.252 ±0.008
AMS494
Mechanical Dimensions (Continued)
Package
16-SOP
0.05
0.002
0.51
)
0.020
MIN
#9
1.27
0.050
1.80
MAX
0.071
8°
MAX0.10
MAX0.004
3.95 ±0.20
0.156 ±0.008
0~
+0.10
0.20 -0.05
+0.004
0.008 -0.002
6.00 ±0.30
0.236 ±0.012
5.72
0.225
+0.10
0.406 -0.05
+0.004
0.016 -0.002
#8
9.90 ±0.20
0.39 ±0.008
#16
10.30
MAX
0.405
#1
(
1.55 ±0.10
0.061 ±0.004
0.70 ±0.20
0.0275 ±0.008
6
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AMS494
Ordering Information
Product Number
Package
AMS494CN
16 DIP
AMS494CD
16 SOP
Operating Temperature
0 ~ + 70°C
7
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