Order this document by MC34025/D
High Speed Double-Ended
PWM Controller
The MC34025 series are high speed, fixed frequency, double–ended
pulse width modulator controllers optimized for high frequency operation.
They are specifically designed for Off–Line and DC–to–DC converter
applications offering the designer a cost effective solution with minimal
external components. These integrated circuits feature an oscillator, a
temperature compensated reference, a wide bandwidth error amplifier, a
high speed current sensing comparator, steering flip–flop, and dual high
current totem pole outputs ideally suited for driving power MOSFETs.
Also included are protective features consisting of input and reference
undervoltage lockouts each with hysteresis, cycle–by–cycle current limiting,
and a latch for single pulse metering.
The flexibility of this series allows it to be easily configured for either
current mode or voltage mode control.
•
50 ns Propagation Delay to Outputs
MC34025
MC33025
16
1
P SUFFIX
PLASTIC PACKAGE
CASE 648
16
1
•
•
•
•
•
•
•
•
•
•
•
•
Dual High Current Totem Pole Outputs
Wide Bandwidth Error Amplifier
Fully–Latched Logic with Double Pulse Suppression
Latching PWM for Cycle–By–Cycle Current Limiting
Soft–Start Control with Latched Overcurrent Reset
Input Undervoltage Lockout with Hysteresis
Low Start–Up Current (500
µA
Typ)
Internally Trimmed Reference with Undervoltage Lockout
90% Maximum Duty Cycle (Externally Adjustable)
Precision Trimmed Oscillator
Voltage or Current Mode Operation to 1.0 MHz
Functionally Similar to the UC3825
Error Amp
Inverting Input
Error Amp
Noninverting Input
Error Amp Output
Clock
16
Vref
Clock
RT
CT
4
5
Oscillator
6
7
Latching
PWM and
Steering
Flip Flop
5.1V
Reference
UVLO
13
14
VC
Output B
15
VCC
RT
CT
Ramp
Soft–Start
1
2
3
4
5
6
7
8
DW SUFFIX
PLASTIC PACKAGE
CASE 751G
(SO–16L)
PIN CONNECTIONS
16
15
14
13
12
11
10
9
Vref
VCC
Output B
VC
Power Ground
Output A
Ground
Current Limit/
Shutdown
Simplified Application
(Top View)
Ramp
Error Amp 3
Output
Noninverting 2
Input
Inverting
Input 1
8
Soft–Start
Error
Amp
11
Output A
Power
12 Ground
9
Current
Limit/
Shutdown
ORDERING INFORMATION
Device
MC33025DW
MC33025P
MC34025DW
MC34025P
TA = 0° to +70°C
Operating
Temperature Range
TA = – 40° to +105°C
Package
SO–16L
Plastic DIP
SO–16L
Plastic DIP
Soft–Star
t
10
Ground
This device contains 227 active transistors.
©
Motorola, Inc. 1996
Rev 1
MOTOROLA ANALOG IC DEVICE DATA
1
MC34025 MC33025
MAXIMUM RATINGS
Rating
Power Supply Voltage
Output Driver Supply Voltage
Output Current, Source or Sink (Note 1)
DC
Pulsed (0.5
µs)
Current Sense, Soft–Start, Ramp, and Error Amp Inputs
Error Amp Output and Soft–Start Sink Current
Clock and RT Output Current
Power Dissipation and Thermal Characteristics
SO–16 Package (Case 751G)
Maximum Power Dissipation @ TA = + 25°C
Thermal Resistance, Junction–to–Air
DIP Package (Case 648)
Maximum Power Dissipation @ TA = + 25°C
Thermal Resistance, Junction–to–Air
Operating Junction Temperature
Operating Ambient Temperature (Note 2)
MC34025
MC33025
Storage Temperature Range
Symbol
VCC
VC
IO
0.5
2.0
Vin
IO
ICO
– 0.3 to +7.0
10
5.0
V
mA
mA
Value
30
20
Unit
V
V
A
PD
R
θJA
PD
R
θJA
TJ
TA
Tstg
862
145
1.25
100
+150
0 to +70
– 40 to +105
– 55 to +150
mW
°C/W
W
°C/W
°C
°C
°C
ELECTRICAL CHARACTERISTICS
(VCC = 15 V, RT = 3.65 kΩ, CT = 1.0 nF, for typical values TA = + 25°C, for min/max values TA is
the operating ambient temperature range that applies [Note 2], unless otherwise noted.)
Characteristic
REFERENCE SECTION
Reference Output Voltage (IO = 1.0 mA, TJ = + 25°C)
Line Regulation (VCC = 10 V to 30 V)
Load Regulation (IO = 1.0 mA to 10 mA)
Temperature Stability
Total Output Variation over Line, Load, and Temperature
Output Noise Voltage (f = 10 Hz to 10 kHz, TJ = + 25°C)
Long Term Stability (TA = +125°C for 1000 Hours)
Output Short Circuit Current
OSCILLATOR SECTION
Frequency
TJ = + 25°C
Line (VCC = 10 V to 30 V) and Temperature (TA = Tlow to Thigh)
Frequency Change with Voltage (VCC = 10 V to 30 V)
Frequency Change with Temperature (TA = Tlow to Thigh)
Sawtooth Peak Voltage
Sawtooth Valley Voltage
Clock Output Voltage
High State
Low State
kHz
fosc
∆f
osc/∆V
∆f
osc/∆T
VP
VV
VOH
VOL
380
370
–
–
2.6
0.7
3.9
–
400
400
0.2
2.0
2.8
1.0
4.5
2.3
420
430
1.0
–
3.0
1.25
–
2.9
%
%
V
V
V
Vref
Regline
Regload
TS
Vref
Vn
S
ISC
5.05
–
–
–
4.95
–
–
–30
5.1
2.0
2.0
0.2
–
50
5.0
–65
5.15
15
15
–
5.25
–
–
–100
V
mV
mV
mV/°C
V
µV
mV
mA
Symbol
Min
Typ
Max
Unit
NOTES:
1. Maximum package power dissipation limits must be observed.
2. Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible.
T
low
= 0°C for MC34025
T
high
= +70°C for MC34025
T
low
= – 40°C for MC33025
T
high
= +105°C for MC33025
2
MOTOROLA ANALOG IC DEVICE DATA
MC34025 MC33025
ELECTRICAL CHARACTERISTICS
(VCC = 15 V, RT = 3.65 kΩ, CT = 1.0 nF, for typical values TA = + 25°C, for min/max values
TA is the operating ambient temperature range that applies [Note 2], unless otherwise noted.)
Characteristic
ERROR AMPLIFIER SECTION
Input Offset Voltage
Input Bias Current
Input Offset Current
Open–Loop Voltage Gain (VO = 1.0 V to 4.0 V)
Gain Bandwidth Product (TJ = + 25°C)
Common Mode Rejection Ratio (VCM = 1.5 V to 5.5 V)
Power Supply Rejection Ratio (VCC = 10 V to 30 V)
Output Current, Source (VO = 4.0 V)
Output Current,
Sink (VO = 1.0 V)
Output Voltage Swing, High State (IO = – 0.5 mA)
Output Voltage Swing,
Low State (IO = 1.0 mA)
Slew Rate
PWM COMPARATOR SECTION
Ramp Input Bias Current
Duty Cycle, Maximum
Duty Cycle,
Minimum
Zero Duty Cycle Threshold Voltage Pin 3(4) (Pin 7(9) = 0 V)
Propagation Delay (Ramp Input to Output, TJ = + 25°C)
SIFT–START SECTION
Charge Current (VSoft–Start = 0.5 V)
Discharge Current (VSoft–Start = 1.5 V)
CURRENT SENSE SECTION
Input Bias Current (Pin 9(12) = 0 V to 4.0 V)
Current Limit Comparator Threshold
p
Shutdown C
Sh td
Comparator Threshold
t Th h ld
Propagation Delay (Current Limit/Shutdown to Output, TJ = + 25°C)
OUTPUT SECTION
Output Voltage
Low State (ISink = 20 mA)
(ISink = 200 mA)
High State (ISource = 20 mA)
(ISource = 200 mA)
Output Voltage with UVLO Activated (VCC = 6.0 V, ISink = 0.5 mA)
Output Leakage Current (VC = 20 V)
Output Voltage Rise Time (CL = 1.0 nF, TJ = + 25°C)
Output Voltage Fall Time (CL = 1.0 nF, TJ = + 25°C)
UNDERVOLTAGE LOCKOUT SECTION
Start–Up Threshold (VCC Increasing)
UVLO Hysteresis Voltage (VCC Decreasing After Turn–On)
TOTAL DEVICE
Power Supply Current
Start–Up (VCC = 8.0 V)
Operating
ICC
–
–
0.5
25
1.2
35
mA
Vth(on)
VH
8.8
0.4
9.2
0.8
9.6
1.2
V
V
V
VOL
VOH
VOL(UVLO)
IL
tr
tf
–
–
13
12
–
–
–
–
0.25
1.2
13.5
13
0.25
100
30
30
0.4
2.2
–
–
1.0
500
60
60
V
µA
ns
ns
IIB
Vth
Vth
tPLH(in/out)
–
0.9
1.25
1 25
–
–
1.0
1.40
1 40
50
15
1.10
1.55
1 55
80
µA
V
ns
Ichg
Idischg
3.0
1.0
9.0
4.0
20
–
µA
mA
IIB
DC(max)
DC(min)
Vth
tPLH(in/out)
–
80
–
1.1
–
– 0.5
90
–
1.25
60
– 5.0
–
0
1.4
100
µA
%
V
ns
VIO
IIB
IIO
AVOL
GBW
CMRR
PSRR
ISource
ISink
VOH
VOL
SR
–
–
–
60
4.0
75
85
0.5
1.0
4.5
0
6.0
–
0.6
0.1
95
8.3
95
110
3.0
3.6
4.75
0.4
12
15
3.0
1.0
–
–
–
–
–
–
5.0
1.0
–
mV
µA
µA
dB
MHz
dB
dB
mA
V
V/µs
Symbol
Min
Typ
Max
Unit
NOTES:
1. Maximum package power dissipation limits must be observed.
2. Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible.
T
low
= 0°C for MC34025
T
high
= +70°C for MC34025
T
high
= +105°C for MC33025
T
low
= – 40°C for MC33025
MOTOROLA ANALOG IC DEVICE DATA
3
MC34025 MC33025
Figure 1. Timing Resistor versus
Oscillator Frequency
100 k
1
R T , TIMING RESISTOR (
Ω
)
3
2
5
4
7
6
9
8
f osc , OSCILLATOR FREQUENCY (kHz)
VCC = 15 V
TA = + 25°C
Figure 2. Oscillator Frequency versus Temperature
1200
1000
800
600
400
200
50 kHz
0
– 55
– 25
50
0
25
75
TA, AMBIENT TEMPERATURE (°C)
VCC = 15 V
400 kHz
RT = 3.6 k
CT = 1.0 nF
RT = 36 k
CT = 1.0 nF
100
125
1.0 MHz
RT = 1.2 k
CT = 1.0 nF
CT=
10 k 1. 100 nF
2. 47 nF
3. 22 nF
4. 10 nF
5. 4.7 nF
6. 2.2 nF
1.0 k 7. 1.0 nF
8. 470 pF
9. 220 pF
470
100
1000
104
105
106
fosc, OSCILLATOR FREQUENCY (Hz)
107
Figure 3. Error Amp Open Loop Gain and
Phase versus Frequency
A VOL , OPEN LOOP VOLTAGE GAIN (dB)
120
100
V th, ZERO DUTY CYCLE (V)
1.28
, EXCESS PHASE (°C)
80
Gain
60
Phase
40
20
0
– 20
10
100
1.0 k
10 k
100 k
f, FREQUENCY (Hz)
1.0 M
90
45
0
1.3
Figure 4. PWM Comparator Zero Duty Cycle
Threshold Voltage versus Temperature
VCC = 15 V
Pin 7(9) = 0 V
1.26
1.24
1.22
1.2
–55
135
10 M
θ
–25
0
25
50
75
TA, AMBIENT TEMPERATURE (°C)
100
125
Figure 5. Error Amp Small Signal
Transient Response
Figure 6. Error Amp Large Signal
Transient Response
2.55 V
3.0 V
2.5 V
2.5 V
2.45 V
0.1
µs/DIV
2.0 V
0.1
µs/DIV
4
MOTOROLA ANALOG IC DEVICE DATA
MC34025 MC33025
I SC , REFERENCE SHORT CIRCUIT CURRENT (mA)
Figure 7. Reference Voltage Change
versus Source Current
Vref , REFERENCE VOLTAGE CHANGE (mV)
0
–5.0
–10
–15
–20
–25
–30
0
10
20
30
40
ISource, SOURCE CURRENT (mA)
50
VCC = 15 V
TA = – 55°C
TA = +125°C
TA = + 25°C
Figure 8. Reference Short Circuit Current
versus Temperature
66
65.6
65.2
64.8
64.4
64
–55
VCC = 15 V
– 25
0
25
50
75
TA, AMBIENT TEMPERATURE (°C)
100
125
Figure 9. Reference Line Regulation
Figure 10. Reference Load Regulation
2.0 mV/DIV
Vref LINE REGULATION 10 V – 24 V
2.0 ms/DIV
2.0 mV/DIV
Vref LINE REGULATION 1.0 mA – 10 mA
2.0 ms/DIV
∆
Vth(CL), CURRENT LIMIT THRESHOLD CHANGE (mV)
Figure 11. Current Limit Comparator Threshold
Change versus Temperature
2.0
0
– 2.0
– 4.0
– 6.0
– 8.0
–10
–12
– 50
– 25
0
25
50
75
TA, AMBIENT TEMPERATURE (°C)
100
125
Vth , SHUTDOWN THRESHOLD VOLTAGE (V)
4.0
1.50
1.46
1.42
1.38
1.34
1.30
–55
Figure 12. Shutdown Comparator Threshold
Voltage versus Temperature
VCC = 15 V
–25
0
25
50
75
TA, AMBIENT TEMPERATURE (°C)
100
125
MOTOROLA ANALOG IC DEVICE DATA
5
Analog electronics
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