Datasheet UCC3805PWTR, UCC3805PW, UCC1800J, UCC1805J883B, UCC1805J Datasheet (Texas Instruments)
...
UCC1800/1/2/3/4/5
UCC2800/1/2/3/4/5
UCC3800/1/2/3/4/5
03/99
FEATURES
• 100
µA Typical Starting Supply Current
• 500
µA Typical Operating Supply
Current
• Operation to 1MHz
• Internal Soft Start
• Internal Fault Soft Start
• Internal Leading-Edge Blanking of the
Current Sense Signal
• 1 Amp Totem-Pole Output
• 70ns Typical Response from
Current-Sense to Gate Drive Output
• 1.5% Tolerance Voltage Reference
• Same Pinout as UC3842 and
UC3842A
DESCRIPTION
The UCC1800/1/2/3/4/5 family of high-speed, low-power integrated circuits contain all of the control and drive components required for off-line
and DC-to-DC fixed frequency current-mode switching power supplies
with minimal parts count.
These devices have the same pin configuration as the UC1842/3/4/5
family, and also offer the added features of internal full-cycle soft start
and internal leading-edge blanking of the current-sense input.
The UCC1800/1/2/3/4/5 family offers a variety of package options, temperature range options, choice of maximum duty cycle, and choice of critical voltage levels. Lower reference parts such as the UCC1803 and
UCC1805 fit best into battery operated systems, while the higher reference and the higher UVLO hysteresis of the UCC1802 and UCC1804
make these ideal choices for use in off-line power supplies.
The UCC180x series is specified for operation from –55
o
C to +125oC,
the UCC280x series is specified for operation from –40
o
Cto+85oC, and
the UCC380x series is specified for operation from 0
o
C to +70oC.
Low-Power BiCMOS Current-Mode PWM
Part Number Maximum Duty Cycle Reference Voltage Turn-On Threshold Turn-Off Threshold
UCCx800 100% 5V 7.2V 6.9V
UCCx801 50% 5V 9.4V 7.4V
UCCx802 100% 5V 12.5V 8.3V
UCCx803 100% 4V 4.1V 3.6V
UCCx804 50% 5V 12.5V 8.3V
UCCx805 50% 4V 4.1V 3.6V
BLOCK DIAGRAM
UDG92009-3
2
UCC1800/1/2/3/4/5
UCC2800/1/2/3/4/5
UCC3800/1/2/3/4/5
DIL-8, SOIC-8 (Top View)
J or N, D Package
ELECTRICAL CHARACTERISTICS Unless otherwise stated, these specifications apply for –55°C ≤ T
A
≤ +125°C for
UCC180x; –40°C ≤ TA≤ +85°C for UCC280x; 0°C ≤ TA≤ +70°C for UCC380x; VCC=10V (Note 3); RT=100k from REF to RC;
CT=330pF from RC to GND; 0.1µF capacitor from VCCto GND; 0.1µF capacitor from V
REF
to GND. TA=TJ.
PARAMETER TEST CONDITIONS UCC180X
UCC280X
UCC380X UNITS
MIN TYP MAX MIN TYP MAX
Reference Section
Output Voltage T
J
=+25°C, I=0.2mA, UCCx800/1/2/4 4.925 5.00 5.075 4.925 5.00 5.075 V
T
J
=+25°C, I=0.2mA, UCCx803/5 3.94 4.00 4.06 3.94 4.00 4.06
Load Regulation 0.2mA<I<5mA 10 30 10 25 mV
Total Variation UCCx800/1/2/4 (Note 7) 4.88 5.00 5.10 4.88 5.00 5.10 V
UCCx803/5 (Note 7) 3.90 4.00 4.08 3.90 4.00 4.08 V
Output Noise Voltage 10Hz ≤ f ≤ 10kHz, T
J
=+25°C (Note 9) 130 130 µV
Long Term Stability T
A
=+125°C, 1000 Hours (Note 9) 5 5 mV
Output Short Circuit –5 –35 –5 –35 mA
Oscillator Section
Oscillator Frequency UCCx800/1/2/4 (Note 4) 40 46 52 40 46 52 kHz
UCCx803/5 (Note 4) 26 31 36 26 31 36 kHz
Temperature Stability (Note 9) 2.5 2.5 %
Amplitude peak-to-peak 2.25 2.40 2.55 2.25 2.40 2.55 V
Oscillator Peak Voltage 2.45 2.45 V
OUT
VCC
REF
GND
1
2
3
4
8
7
6
5
FB
COMP
CS
RC
ABSOLUTE MAXIMUM RATINGS (Note 1)
VCCVoltage (Note 2). . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.0V
VCCCurrent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30.0mA
OUT Current. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±1.0A
OUT Energy (Capacitive Load) . . . . . . . . . . . . . . . . . . . 20.0µJ
Analog Inputs (FB, CS). . . . . . . . . . . . . . . . . . . . –0.3V to 6.3V
Power Dissipation at TA< +25°C (N or J Package) . . . . . 1.0W
Power Dissipation at TA< +25°C (D Package). . . . . . . . 0.65W
Storage Temperature Range. . . . . . . . . . . . . –65°C to +150°C
Lead Temperature (Soldering, 10 Seconds) . . . . . . . . +300°C
Note 1: All voltages are with respect to GND.All currents are
positive into the specified terminal. Consult Unitrode
databook for information regarding thermal specifications and limitations of packages.
Note 2: In normal operation V
CC
is powered through a current
limiting resistor.Absolute maximum of 12V applies
when V
CC
is driven from a low impedance source such
that I
CC
does not exceed 30mA.
COMP
FB
CS
RC
REF
VCC
OUT
GND
8
7
6
5
1
2
3
4
CONNECTION DIAGRAMS
TSSOP-8 (Top View)
PW Package
UCC
PRODUCT OPTION
PACKAGE
80
TEMPERATURE RANGE
ORDERING INFORMATION
Temperature Range Available Packages
UCC1800 –55°C to +125°C J
UCC2800 –40°C to +85°C N, D, PW
UCC3800 0°C to +70°C N, D, PW
TEMPERATURE AND PACKAGE SELECTION
3
UCC1800/1/2/3/4/5
UCC2800/1/2/3/4/5
UCC3800/1/2/3/4/5
ELECTRICAL CHARACTERISTICS
Unless otherwise stated, these specifications apply for –55°C ≤ TA≤ +125°C for
UCC180x; –40°C ≤ TA≤ +85°C for UCC280x; 0°C ≤ TA≤ +70°C for UCC380x; VCC=10V (Note 3); RT=100k from REF to RC;
CT=330pF from RC to GND; 0.1µF capacitor from VCCto GND; 0.1µF capacitor from V
REF
to GND. TA=TJ.
PARAMETER TEST CONDITIONS UCC180X
UCC280X
UCC380X UNITS
Error Amplifier Section
Input Voltage COMP=2.5V; UCCx800/1/2/4 2.44 2.50 2.56 2.44 2.50 2.56 V
COMP=2.0V; UCCx803/5 1.95 2.0 2.05 1.95 2.0 2.05
Input Bias Current
–11–11µA
Open Loop Voltage Gain 60 80 60 80 dB
COMP Sink Current FB=2.7V, COMP=1.1V 0.3 3.5 0.4 2.5 mA
COMP Source Current FB=1.8V, COMP=REF–1.2V –0.2 –0.5 –0.8 –0.2 –0.5 –0.8 mA
Gain Bandwidth Product (Note 9) 2 2 MHz
PWM Section
Maximum Duty Cycle UCCx800/2/3 97 99 100 97 99 100 %
UCCx801/4/5 48 49 50 48 49 50
Minimum Duty Cycle COMP=0V 0 0 %
Current Sense Section
Gain (Note 5) 1.10 1.65 1.80 1.10 1.65 1.80 V/V
Maximum Input Signal COMP=5V (Note 6) 0.9 1.0 1.1 0.9 1.0 1.1 V
Input Bias Current
–200 200 –200 200 nA
CS Blank Time 50 100 150 50 100 150 ns
Over-Current Threshold 1.42 1.55 1.68 1.42 1.55 1.68 V
COMP to CS Offset CS=0V 0.45 0.90 1.35 0.45 0.90 1.35 V
Output Section
OUT Low Level I=20mA, all parts 0.1 0.4 0.1 0.4 V
I=200mA, all parts 0.35 0.90 0.35 0.90 V
I=50mA, VCC=5V, UCCx803/5 0.15 0.40 0.15 0.40 V
I=20mA, VCC=0V, all parts 0.7 1.2 0.7 1.2 V
OUT High V
SAT
(VCC-OUT)
I=–20mA, all parts 0.15 0.40 0.15 0.40 V
I=–200mA, all parts 1.0 1.9 1.0 1.9 V
I=–50mA,VCC=5V, UCCx803/5 0.4 0.9 0.4 0.9 V
Rise Time C
L
=1nF 41 70 41 70 ns
Fall Time C
L
=1nF 44 75 44 75 ns
Undervoltage Lockout Section
Start Threshold (Note 8) UCCx800 6.6 7.2 7.8 6.6 7.2 7.8 V
UCCx801 8.6 9.4 10.2 8.6 9.4 10.2 V
UCCx802/4 11.5 12.5 13.5 11.5 12.5 13.5 V
UCCx803/5 3.7 4.1 4.5 3.7 4.1 4.5 V
Stop Threshold (Note 8) UCCx1800 6.3 6.9 7.5 6.3 6.9 7.5 V
UCCx1801 6.8 7.4 8.0 6.8 7.4 8.0 V
UCCx802/4 7.6 8.3 9.0 7.6 8.3 9.0 V
UCCx803/5 3.2 3.6 4.0 3.2 3.6 4.0 V
Start to Stop Hysteresis UCCx800 0.12 0.3 0.48 0.12 0.3 0.48 V
UCCx801 1.6 2 2.4 1.6 2 2.4 V
UCCx802/4 3.5 4.2 5.1 3.5 4.2 5.1 V
UCCx803/5 0.2 0.5 0.8 0.2 0.5 0.8 V
4
UCC1800/1/2/3/4/5
UCC2800/1/2/3/4/5
UCC3800/1/2/3/4/5
ELECTRICAL CHARACTERISTICS
Unless otherwise stated, these specifications apply for –55°C ≤ TA≤ +125°C for
UCC180x; –40°C ≤ TA≤ +85°C for UCC280x; 0°C ≤ TA≤ +70°C for UCC380x; VCC=10V (Note 3); RT=100k from REF to RC;
CT=330pF from RC to GND; 0.1µF capacitor from VCCto GND; 0.1µF capacitor from V
REF
to GND. TA=TJ.
PARAMETER TEST CONDITIONS UCC180X
UCC280X
UCC380X UNITS
Soft Start Section
COMP Rise Time FB=1.8V, Rise from 0.5V to REF–1V 4 10 4 10 ms
Overall Section
Start-up Current V
CC
< Start Threshold 0.1 0.2 0.1 0.2 mA
Operating Supply Current FB=0V, CS=0V 0.5 1.0 0.5 1.0 mA
VCC Internal Zener Voltage I
CC
=10mA (Note 8) 12 13.5 15 12 13.5 15 V
VCC Internal Zener Voltage Minus
Start Threshold Voltage
UCCx802/4 0.5 1.0 0.5 1.0 V
Note 3: Adjust VCC above the start threshold before setting at 10V.
Note 4: Oscillator frequency for the UCCx800, UCCx802 and UCCx803 is the output frequency.
Oscillator frequency for the UCCx801, UCCx804 and UCCx805 is twice the output frequency.
Note 5: Gain is defined by:
A
V
V
VV
COMP
CS
CS
=≤≤
∆
∆
008.
.
Note 6: Parameter measured at trip point of latch with Pin 2 at 0V.
Note 7: Total Variation includes temperature stability and load regulation.
Note 8: Start Threshold, Stop Threshold and Zener Shunt Thresholds track one another.
Note 9: Guaranteed by design. Not 100% tested in production.
PIN DESCRIPTIONS
COMP: COMP is the output of the error amplifier and the
input of the PWM comparator.
Unlike other devices, the error amplifier in the UCC3800
family is a true, low output-impedance, 2MHz operational
amplifier. As such, the COMP terminal can both source
and sink current. However, the error amplifier is internally
current limited, so that you can command zero duty cycle
by externally forcing COMP to GND.
The UCC3800 family features built-in full cycle Soft Start.
Soft Start is implemented as a clamp on the maximum
COMP voltage.
CS: CS is the input to the current sense comparators.
The UCC3800 family has two different current sense
comparators: the PWM comparator and an over-current
comparator.
The UCC3800 family contains digital current sense filtering, which disconnects the CS terminal from the current
sense comparator during the 100ns interval immediately
following the rising edge of the OUT pin. This digital filtering, also called leading-edge blanking, means that in
most applications, no analog filtering (RC filter) is required on CS. Compared to an external RC filter technique, the leading-edge blanking provides a smaller
effective CS to OUT propagation delay. Note, however,
that the minimum non-zero On-Time of the OUT signal is
directly affected by the leading-edge-blanking and the
CS to OUT propagation delay.
The over-current comparator is only intended for fault
sensing, and exceeding the over-current threshold will
cause a soft start cycle.
FB: FB is the inverting input of the error amplifier. For
best stability, keep FB lead length as short as possible
and FB stray capacitance as small as possible.
GND: GND is reference ground and power ground for all
functions on this part.
OUT: OUT is the output of a high-current power driver
capable of driving the gate of a power MOSFET with
peak currents exceeding ± 750mA. OUT is actively held
low when V
CC
is below the UVLO threshold.
The high-current power driver consists of FET output devices, which can switch all of the way to GND and all of
thewaytoV
CC
. The output stage also provides a very
low impedance to overshoot and undershoot. This means
that in many cases, external schottky clamp diodes are
not required.
5
UCC1800/1/2/3/4/5
UCC2800/1/2/3/4/5
UCC3800/1/2/3/4/5
RC: RC is the oscillator timing pin. For fixed frequency
operation, set timing capacitor charging current by connecting a resistor from REF to RC. Set frequency by connecting a timing capacitor from RC to GND. For best
performance, keep the timing capacitor lead to GND as
short and direct as possible. If possible, use separate
ground traces for the timing capacitor and all other functions.
The frequency of oscillation can be estimated with the
following equations:
UCCx800/1/2/4:
F
RC
=
•
15.
UCCx803, UCCx805:
F
RC
=
•
10.
where frequency is in Hz, resistance is in ohms, and capacitance is in farads. The recommended range of timing
resistors is between 10k and 200k and timing capacitor is
100pF to 1000pF. Never use a timing resistor less than
10k.
To prevent noise problems, bypass VCC to GND with a
ceramic capacitor as close to the VCC pin as possible.
An electrolytic capacitor may also be used in addition to
the ceramic capacitor.
REF: REF is the voltage reference for the error amplifier
and also for many other functions on the IC. REF is also
used as the logic power supply for high speed switching
logic on the IC.
When V
CC
is greater than 1V and less than the UVLO
threshold, REF is pulled to ground through a 5k ohm resistor. This means that REF can be used as a logic output indicating power system status. It is important for
reference stability that REF is bypassed to GND with a
ceramic capacitor as close to the pin as possible. An
electrolytic capacitor may also be used in addition to the
ceramic capacitor. A minimum of 0.1µF ceramic is required. Additional REF bypassing is required for external
loads greater than 2.5mA on the reference.
To prevent noise problems with high speed switching
transients, bypass REF to ground with a ceramic capacitor very close to the IC package.
VCC: V
CC
is the power input connection for this device.
In normal operation V
CC
is powered through a current
limiting resistor. Although quiescent V
CC
current is very
low, total supply current will be higher, depending on
OUT current. Total V
CC
current is the sum of quiescent
V
CC
current and the average OUT current. Knowing the
operating frequency and the MOSFET gate charge (Qg),
average OUT current can be calculated from:
IQF
OUT
g
=×
.
PIN DESCRIPTIONS (cont.)
Figure 1. Oscillator.
Figure 2. Error amplifier gain/phase response.
The UCC3800/1/2/3/4/5 oscillator generates a sawtooth
waveform on RC.The rise time is set by the time constant of
R
T
and CT. The fall time is set by CT and an internal transis-
tor on-resistance of approximately 125
Ω
. During the fall
time, the output is off and the maximum duty cycle is reduced below 50% or 100% depending on the part number.
Larger timing capacitors increase the discharge time and reduce the maximum duty cycle and frequency.
6
UCC1800/1/2/3/4/5
UCC2800/1/2/3/4/5
UCC3800/1/2/3/4/5
1000
100
10
10 100 1000
Oscillator Freq. (kHz)
R(k)
T
100pF
200pF
330pF
1nF
Figure 5. UCC1803/5 oscillator frequency vs. RTand
C
T.
95
95.5
96
96.5
97
97.5
98
98.5
99
99.5
100
10 100 1000
Oscillator Frequency (kHz)
Maximum Duty Cycle (%)
C = 100pF
T
C = 200pF
T
C = 330pF
T
Figure 6. UCC1800/2/3 maximum duty cycle vs.
oscillator frequency.
1000
100
10
10 100 1000
Oscillator Freq. (kHz)
R(k)
T
100pF
200pF
330pF
1nF
Figure 4. UCC1800/1/2/4 oscillator frequency vs. R
T
and CT.
4.00
3.98
3.96
3.94
3.92
3.90
3.88
3.86
3.84
3.82
4 4.2 4.4 4.6 4.8
5
5.2 5.4 5.6 5.8 6
V (V)
CC
V (V)
REF
Figure 3. UCC1803/5 V
REF
vs. VCC;I
LOAD
= 0.5mA.
46.5
47
47.5
48
48.5
49
49.5
50
10 100 1000
Oscillator Frequency (kHz)
Maximum Duty Cycle (%)
C = 100pF
T
C = 200pF
T
C = 330pF
T
Figure 7. UCC1801/4/5 maximum duty cycle vs.
oscillator frequency.
0
2
4
6
8
10
12
14
16
0 100 200 300 400 500 600 700 800 900 1000
Oscillator Frequency (kHz)
I (mA)
CC
V = 10V, 1nF
CC
V = 8V, 1nF
CC
V = 10V, No Load
CC
V = 8V, No Load
CC
Figure 8. UCC1800 ICCvs. oscillator frequency.
7
UCC1800/1/2/3/4/5
UCC2800/1/2/3/4/5
UCC3800/1/2/3/4/5
0
50
100
150
200
250
300
350
400
450
500
100 200 300 400 500 600 700 800 900 1000
C (pF)
T
Dead Time (ns)
UCC1803/5
UCC1800/1/2/4
Figure 9. Dead time vs. CT,RT= 100k.
0
0.6
0.7
0.8
0.9
1.0
1.1
-55-50 -25 0 25 50 75 100 125
Temperature (°C)
COMP to CS Offset (Volts)
Slope = 1.8mV/ C
°
Figure 10. COMP to CS offset vs. temperature,
CS = 0V.
0
1
2
3
4
5
6
7
8
0 100 200 300 400 500 600 700 800 900 1000
Oscillator Frequency (kHz)
I (mA)
CC
V = 10V, 1nF
CC
V = 8V, 1nF
CC
V = 10V, No Load
CC
V = 8V, No Load
CC
Figure 8. UCC1805 ICCvs. oscillator frequency.
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