The MC34065 is a high performance, fixed frequency , dual current mode
controllers. It is specifically designed for off–line and dc–to–dc converter
applications offering the designer a cost effective solution with minimal
external components. This integrated circuit feature a unique oscillator for
precise duty cycle limit and frequency control, a temperature compensated
reference, two high gain error amplifiers, two current sensing comparators,
Drive Output 2 Enable pin, and two 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 of each output.
The MC34065 and MC33065 are available in dual–in–line and surface
mount packages.
• Unique Oscillator for Precise Duty Cycle Limit and Frequency Control
• Current Mode Operation to 500 kHz
• Automatic Feed Forward Compensation
• Separate Latching PWMs for Cycle–By–Cycle Current Limiting
• Internally Trimmed Reference with Undervoltage Lockout
• Drive Output 2 Enable Pin
• Two High Current Totem Pole Outputs
• Input Undervoltage Lockout with Hysteresis
• Low Startup and Operating Current
HIGH PERFORMANCE
DUAL CHANNEL CURRENT
MODE CONTROLLER
SEMICONDUCTOR
TECHNICAL DATA
P SUFFIX
PLASTIC PACKAGE
CASE 648
DW SUFFIX
PLASTIC PACKAGE
CASE 751G
(SO–16L)
16
1
16
1
Representative Block Diagram
V
ref
Lockout
5.0 V
Reference
V
ref
Sync Input
R
T
C
T
Voltage
Feedback 1
Compensation 1
Drive Output 2
Enable
Voltage
Feedback 2
Compensation 2
15
1
3
2
4
5
14
13
12
R
R
Undervoltage
Oscillator
+
–
Error
Amp 1
+
–
Error
Amp 2
Gnd 8Drive Gnd 9
This device contains 208 active transistors.
MOTOROLA ANALOG IC DEVICE DATA
V
CC
Undervoltage
Lockout
Latching
PWM 1
Latching
PWM 2
PIN CONNECTIONS
V
16
CC
Drive
Output 1
7
Current
Sense 1
6
Drive
Output 2
10
Current
Sense 2
11
Motorola, Inc. 1996Rev 1
Sync Input
Voltage Feedback 1
Compensation 1
Current Sense 1
Drive Output 1
ORDERING INFORMATION
Device
MC34065DW
MC34065P
MC33065DW
MC33065P
1
2
C
T
3
R
T
4
5
6
7
89
Gnd
(Top View)
Operating
Temperature Range
TA = 0° to +70°C
TA = –40° to +85°C
16
V
CC
15
V
ref
Drive Output 2
14
Enable
13
Voltage Feedback 2
12
Compensation 2
11
Current Sense 2
10
Drive Output 2
Drive Gnd
Package
SO–16L
Plastic DIP
SO–16L
Plastic DIP
1
MC34065 MC33065
MAXIMUM RATINGS
RatingSymbolValueUnit
Total Power Supply and Zener Current(ICC + IZ)50mA
Output Current, Source or Sink (Note 1)I
O
Output Energy (Capacitive Load per Cycle)W5.0µJ
Current Sense, Enable, and Voltage Feedback InputsV
in
Sync Input
High State (Voltage)V
Low State (Reverse Current)I
Error Amp Output Sink CurrentI
IH
IL
O
Power Dissipation and Thermal Characteristics
DW Suffix, Plastic Package Case 751G
Maximum Power Dissipation @ TA = 25°CP
Thermal Resistance, Junction–to–AirR
D
θJA
P Suffix, Plastic Package Case 648
Maximum Power Dissipation @ TA = 25°CP
Thermal Resistance, Junction–to–AirR
= 15 V [Note 2], RT = 8.2 kΩ, CT = 3.3 nF, for typical values TA = 25°C, for
CC
min/max values TA is the operating ambient temperature range that applies [Note 3].)
Characteristics
SymbolMinTypMaxUnit
REFERENCE SECTION
Reference Output Voltage (IO = 1.0 mA, TJ = 25°C)V
Line Regulation (VCC = 11 V to 15 V)Reg
Load Regulation (IO = 1.0 mA to 10 mA)Reg
Total Output Variation over Line, Load, and TemperatureV
Output Short Circuit CurrentI
ref
line
load
ref
SC
4.95.05.1V
–2.020mV
–3.025mV
4.85–5.15V
30100–mA
OSCILLATOR AND PWM SECTIONS
Total Frequency Variation over Line and Temperaturef
VCC = 11 V to 15 V, TA = T
low
to T
high
osc
MC3406546.54951.5
MC33065454953
Frequency Change with Voltage (VCC = 11 V to 15 V)∆f
/∆V–0.21.0%
osc
Duty Cycle at each Output%
MaximumDC
MinimumDC
max
min
4649.552
––0
Sync Input CurrentµA
High State (Vin = 2.4 V)I
Low State (Vin = 0.8 V)I
NOTES: 1. Maximum package power dissipation limits must be observed.
2.Adjust VCC above the startup threshold before setting to 15 V.
3.Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible:
T
= 0°C for the MC34065T
low
T
= –40°C for the MC33065T
low
4.This parameter is measured at the latch trip point with VFB = 0 V
5.Comparator gain is defined as
AV
+
= +70°C for MC34065
high
= +85°C for MC33065
high
D
V Compensation
D
V Current Sense
IH
IL
–170250
–80160
kHz
2
MOTOROLA ANALOG IC DEVICE DATA
MC34065 MC33065
ELECTRICAL CHARACTERISTICS (continued) (V
= 15 V [Note 2], RT = 8.2 kΩ, CT = 3.3 nF, for typical values TA = 25°C, for
CC
min/max values TA is the operating ambient temperature range that applies [Note 3].)
CharacteristicsUnitMaxTypMinSymbol
ERROR AMPLIFIERS
Voltage Feedback Input (VO = 2.5 V)V
Input Bias Current (VFB = 5.0 V)I
Open Loop Voltage Gain (VO = 2.0 to 4.0 V)A
FB
IB
VOL
2.422.52.58V
–– 0.1–1.0µA
65100–dB
Unity Gain Bandwidth (TJ = 25°C)BW0.71.0–MHz
Power Supply Rejection Ratio (VCC = 11 V to 15 V)PSRR6090–dB
Output CurrentmA
High State (RL = 15 k to ground, VFB = 2.3 V)V
Low State (RL = 15 k to V
, VFB = 2.7 V)V
ref
OH
OL
5.06.2–
–0.81.1
CURRENT SENSE SECTION
Current Sense Input Voltage Gain (Notes 4 and 5)A
Maximum Current Sense Input Threshold (Note 4)V
Input Bias CurrentI
Propagation Delay (Current Sense Input to Output)t
PLN(In/Out)
V
th
IB
2.753.03.25V/V
430480530mV
––2.0–10µA
–150300ns
DRIVE OUTPUT 2 ENABLE PIN
Enable Pin VoltageV
High State (Output 2 Enabled)V
Low State (Output 2 Disabled)V
Low State Input Current (VIL = 0 V)I
IH
IL
IB
3.5–V
ref
0–1.5
100250400µA
DRIVE OUTPUTS
Output VoltageV
Low State (I
High State(I
Output Voltage with UVLO Activated (VCC = 6.0 V, I
Output Voltage Rise T ime (CL = 1.0 nF)t
Output Voltage Fall T ime (CL = 1.0 nF)t
= 20 mA)V
sink
(I
= 200 mA)–1.62.5
sink
= 20 mA)V
source
(I
= 200 mA)1213.4–
source
= 1.0 mA)V
sink
OL
OH
OL(UVLO)
r
f
–0.10.4
1313.5–
–0.11.1V
–28150ns
–25150ns
UNDERVOLTAGE LOCKOUT SECTION
Startup ThresholdV
Minimum Operating Voltage After Turn–OnV
NOTES: 1. Maximum package power dissipation limits must be observed.
2.Adjust VCC above the startup threshold before setting to 15 V.
3.Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible:
T
= 0°C for the MC34065T
low
T
= –40°C for the MC33065T
low
4.This parameter is measured at the latch trip point with VFB = 0 V
5.Comparator gain is defined as
AV
+
= +70°C for MC34065
high
= +85°C for MC33065
high
D
V Compensation
D
V Current Sense
Z
15.51719V
mA
MOTOROLA ANALOG IC DEVICE DATA
3
MC34065 MC33065
PIN FUNCTION DESCRIPTION
PinFunctionDescription
1Sync InputA narrow rectangular waveform applied to this input will synchronize the oscillator. A dc voltage
2C
3R
T
T
4Voltage Feedback 1This pin is the inverting input of Error Amplifier 1. It is normally connected to the switching power
5Compensation 1This pin is the output of Error Amplifier 1 and is made available for loop compensation.
6Current Sense 1A voltage proportional to the inductor current is connected to this input. PWM 1 uses this
7Drive Output 1This pin directly drives the gate of a power MOSFET Q1. Peak currents up to 1.0 A are sourced
8GndThis pin is the control circuitry ground return and is connected back to the source ground.
9Drive GndThis pin is a separate power ground return that is connected back to the power source. It is used
10Drive Output 2This pin directly drives the gate of a power MOSFET Q2. Peak currents up to 1.0 A are sourced
11Current Sense 2A voltage proportional to inductor current is connected to this input. PWM 2 uses this information
12Compensation 2This pin is the output of Error Amplifier 2 and is made available for loop compensation.
13Voltage Feedback 2This pin is the inverting input of Error Amplifier 2. It is normally connected to the switching power
14Drive Output 2 EnableA logic low at this input disables Drive Output 2.
15V
16V
ref
CC
within the range of 2.4 V to 5.5 V will inhibit the oscillator.
Timing capacitor CT connects from this pin to ground setting the free–running oscillator frequency
range.
Resistor RT connects from this pin to ground precisely setting the charge current for CT. RT must
be between 4.0 k and 16 k.
supply output through a resistor divider.
information to terminate conduction of output switch Q1.
and sunk by this pin.
to reduce the effects of switching transient noise on the control circuitry .
and sunk by this pin.
to terminate conduction of output switch Q2.
supply output through a resistor divider.
This is the 5.0 V reference output. It can provide bias for any additional system circuitry.
This pin is the positive supply of the control IC. The minimum operating voltage range after startup
is 11 V to 15.5 V.
Figure 1. Timing Resistor versus
Oscillator Frequency
16
3.3 nF
)
14
Ω
12
10
8.0
, TIMING RESISTOR (k
T
R
6.0
4.0
10 k30 k50 k300 k 500 k100 k1.0 M
5.0 nF
CT=
10 nF
VCC=15V
°
C
TA=25
f
osc, OSCILLATOR FREQUENCY (Hz)
500 pF
1.0 nF
2.2 nF
100 pF
220 pF
330 pF
4
Figure 2. Maximum Output Duty Cycle
50
48
46
44
VCC=15V
42
, DUTY CYCLE MAXIMUM (%)
RT= 4.0 k to 16 k
CL=15pF
max
40
TA = 25
DC
38
10 k30 k50 k300 k 500 k100 k1.0 M
versus Oscillator Frequency
°
f
osc, OSCILLATOR FREQUENCY (Hz)
Output 2
Output 1
MOTOROLA ANALOG IC DEVICE DATA
MC34065 MC33065
Figure 3. Error Amp Small–Signal
Transient Response
2.55 V
2.50 V
2.45 V
1.0 µs/DIV
Figure 5. Error Amp Open Loop Gain and
Phase versus Frequency
100
80
60
40
20
Gain
VCC=15V
AV= –1.0
TA=25
VCC=15V
VO= 1.5 V to 2.5 V
RL= 100 k
°
C
TA=25
Phase
°
C
0
30
60
90
120
3.0 V
2.5 V
20 mV/DIV
2.0 V
Figure 4. Error Amp Large–Signal
Transient Response
1.0 µs/DIV
Figure 6. Current Sense Input Threshold
versus Error Amp Output Voltage
0.6
VCC = 15 V
0.5
0.4
0.3
0.2
TA = 25°C
TA = 125°C
TA = –55°C
VCC=15V
AV= –1.0
°
C
TA=25
200 mV/DIV
, OPEN LOOP VOL TAGE GAIN (dB)
0
VOL
A
–20
101001.0 k10 k100 k1.0 M10 M
f, FREQUENCY (Hz)
Figure 7. Reference V oltage Change
versus Source Current
0
VCC = 15 V
–4.0
–8.0
–12
–16
–20
, REFERENCE VOLTAGE CHANGE (mV)
ref
V
∆
–24
0
20406080100120
I
, REFERENCE SOURCE CURRENT (mA)
ref
TA = 25°C
TA = 125°C
TA = –55°C
, EXCESS PHASE (DEGREES)
150
φ
180
0.1
, CURRENT SENSE INPUT THRESHOLD (V)
0
th
V
01.02.03.04.07.05.06.0
120
100
80
60
, REFERENCE SHORT CIRCUIT CURRENT (mA)
–55
SC
I
VO, ERROR AMP OUTPUT VOLTAGE (V)
Figure 8. Reference Short Circuit Current
versus T emperature
VCC=15V
≤
0.1
R
L
–250255075100125
TA, AMBIENT TEMPERATURE (°C)
Ω
MOTOROLA ANALOG IC DEVICE DATA
5
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