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NTE1722
Integrated Circuit
Pulse Width Modulator (PWM) Control Circuit
Description:
The NTE1722 is a high performance pulse width modulator integrated circuit in an 18–Lead DIP type
package intended for fixed frequency switching regulators and other power control applications.
Functions included in this IC are a temperature compensated voltage reference, sawtooth oscillator,
error amplifier , pulse width modulator, pulse metering and steering logic, and two high current totem
pole outputs ideally suited for driving the capacitance of power FETs at high speeds.
Additional protective features include soft start and undervoltage lockout, digital current limiting,
double pulse inhibit, adjustable dead time and a data latch for single pulse metering. All digital control
ports art TTL and B–series CMOS compatible. Active low logic design allows easy wired–OR connections for maximum flexibility. The versatility of this device enables implementation in single–ended
or push–pull switching regulators that are transformerless or transformer coupled.
Features:
D 8.0 to 35 Volt Operation
D 5.0 Volt ±1% Trimmed Reference
D 1.0Hz to 400kHz Oscillator Range
D Dual Source/Sink Current Outputs: ±100mA
D Digital Current Limiting
D Programmable Dead Time
D Wide Current Limit Common Mode Range
D Guaranteed 6 Unit Synchronization
Absolute Maximum Ratings: (Values beyond which damage may occur)
Supply Voltage, V
Collector Supply Voltage, V
CC
C
Logic Inputs –0.3 to +5.5V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Analog Inputs –0.3 to V
Output Current (Source or Sink), I
O
Reference Load Current (VCC = 40V, Note 1), I
ref
±200mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Logic Sink Current 15mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Dissipation (TA = +25°C), P
D
1000mW. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Derate Above 50°C 10mW/°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Dissipation (TC = +25°C), P
D
3000mW. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Derate Above 25°C 24mW/°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating Junction Temperature, TJ + 150°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage Temperature Range, T
Thermal Resistance, Junction–to–Ambient, R
Lead Temperature (During Soldering, 10sec), T
–65° to +150°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
stg
thJA
L
100°C/W. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
±300°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Note 1. Maximum junction temperature must be observed.
+40V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
+40V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CC
50mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Recommended Operating Conditions:
Parameter Symbol Test Conditions Min Typ Max Unit
Supply Voltage V
Collector Supply Voltage V
Output Sink/Source Current (Each Output) I
Reference Load Current I
Oscillator Frequency Range I
Oscillator Timing Resistor R
Oscillator Timing Capacitor C
CC
C
O
ref
ref
T
T
+8.0 – +35 V
+4.5 – +35 V
0 – ±100 mA
0 – 20 mA
0 – 20 mA
2.0 – 150 kΩ
0.001 – 20 µF
Available Deadtime Range (40kHz) – 3.0 – 50 %
Operating Junction Temperature Range T
J
0 – +125 °C
Electrical Characteristics: (VCC = 15V, TJ = 0° to +125°C unless otherwise specified)
Parameter Symbol Test Conditions Min Typ Max Unit
Referencd Section (IL = 0mA unless otherwise specified)
Reference Output Voltage V
Line Regulation Reg
Load Regulation Reg
Temperature Stability ∆V
ref
Total Reference Output Voltage Variation ∆V
Short Circuit Current I
Uundervoltage Lockout
ref
SC
TJ = +25°C 4.90 5.00 5.10 V
+8.0V ≤ VCC ≤ +35V – 10 30 mV
line
0mA ≤IL ≤ 20mA – 10 50 mV
load
/∆T
J
+8.0V ≤ VCC ≤ +35V,
ref
– 10 – mV
4.85 5.00 5.15 V
0mA ≤ IL ≤ 20mA
V
= 0V, Note 1 25 80 125 mA
ref
Reset Output V oltage – V
= +3.8V – 0.2 0.4 V
ref
V
= +4.8V 2.4 4.8 – V
ref
Oscillator Section (Note 2)
Initial Accuracy – TJ = +25°C – ±3.0 ±8.0 %
Frequency Stability over Power
Supply Range
Frequency Stability over Temperature ∆f
Minimum Frequency f
Maximum Frequency f
Sawtooth Peak Voltage V
Sawtooth Valley Voltage V
∆f
∆V
∆T
min
max
osc(p)
osc(v)
osc
CC
osc
+8.0V ≤ VCC ≤ +35V – 0.5 1.0 %
∆TJ = 0° to +125°C – 2.0 – %
J
RT = 150kΩ, CT = 20µF – 0.5 – Hz
RT = 2kΩ, CT = 0.001µF 400 – – kHz
VCC = +35V – 3.0 3.5 V
VCC = +8V 0.45 0.8 – V
Error Amplifier Section (0V ≤ VCM ≤ +5.2V unless otherwise specified)
Input Offset Voltage V
Input Bias Current I
Input Offset Current I
DC Open Loop Gain A
IO
IB
IO
VOL
RS ≤ 2kΩ – 20 10 mV
– –350 –2000 nA
– 35 200 nA
RL ≥ 10MΩ 60 72 – dB
Note 1. Maximum junction temperature must be observed.
Note 2. f
= 40kHz (RT = 4.12kΩ ± 1%, CT = 0.01µF ± 1%, RD = 0Ω)
OSC
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Electrical Characteristics (Cont’d): (VCC = 15V, TJ = 0° to +125°C unless otherwise specified)
Parameter Symbol Test Conditions Min Typ Max Unit
Error Amplifier Section (Cont’d) (0V ≤ VCM ≤ +5.2V unless otherwise specified)
High Output Voltage V
Low Output Voltage V
OH
OL
V
Pin1
I
Source
V
Pin2
I
Sink
– V
Pin2
= 100µA
– V
Pin1
= 100µA
≥ +150mV,
≥ +150mV,
3.6 4.2 – V
– 0.2 0.4 V
Common Mode Rejection Ratio CMRR RS ≤ 2kΩ 70 94 – dB
Power Supply Rejection Ratio PSRR +12V ≤ VCC ≤ +18V 66 80 – dB
PWM Comparator Section (Note 2)
Minimum Duty Cycle DC
Maximum Duty Cycle DC
min
max
V
compensation
V
compensation
= +0.4V – – 0 %
= +3.6V 45 49 – %
Digital Ports (SYNC, SHUTDOWN, RESET)
Output Voltage, High Logic Level V
Output Voltage, Low Logic Level V
Input Current, High Logic Level I
Input Current, Low Logic Level I
OH
OL
IH
IL
I
= 40µA 2.4 4.0 – V
source
I
= 3.6mA – 0.2 0.4 V
sink
VIH = +2.4V – –125 –200 µA
VIL = +0.4V – –225 –360 µA
Current Limit Comparator Section (0V ≤ VCM ≤ +12V unless otherwise specified)
Sense Voltage V
Input Bias Current I
sense
IB
RS ≤ 50Ω 80 100 120 mV
– –3 –10 µA
Soft–Start Section
Error Clamp Voltage Reset = +0.4V – 0.1 0.4 V
C
Soft–Start Charging Current
I
CS
Reset = +2.4V 50 100 150 µA
Output Drivers (Each Output, VC = +15Vdc unless otherwise specified)
Output High Level V
Output Low Level V
Collector Leakage I
C(Leak)VC
Rise Time t
Fall Time t
Supply Current I
OH
OL
CC
I
= 20mA 12.5 13.5 – V
source
I
= 100mA 12.0 13.0 – V
source
I
= 20mA – 0.2 0.3 V
Sink
I
= 100mA – 1.2 2.0 V
Sink
= +40V – 50 150 µA
CL = 1000pF – 0.3 0.6 µs
r
f
Shutdown + +0.4V, VCC = +35V,
– 0.1 0.2 µs
– 18 30 mA
RT = 4.12kΩ
Note 2. f
= 40kHz (RT = 4.12kΩ ± 1%, CT = 0.01µF ± 1%, RD = 0Ω)
OSC
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Pin Connection Diagram
Error (+)
Error (–)
Compensation
C
SOFT–START
Reset
1
2
3
4
5
6Current Sense (–)
7Current Sense (+)
Shutdown
8
9 10
R
T
18 10
V
18
ref
17
V
CC
1615Output B
GND
14
V
C
13
Output A
12
Sync
11
R
D
C
T
19
.870 (22.1) Max
.250 (6.35)
.150
(3.8)
.100 (2.54) .125 (3.17) Min
.800 (20.3)
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