UCC3880DWTR-4 [TI]
Pentium Pro Controller;
| 型号： | UCC3880DWTR-4 |
| 厂家： | 
TEXAS INSTRUMENTS |
| 描述： | Pentium Pro Controller 信息通信管理 开关 光电二极管 |
| 文件： | 总8页 (文件大小：340K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
UCC2880-4/-5/-6
UCC3880-4/-5/-6
PRELIMINARY
Pentium® Pro Controller
FEATURES
DESCRIPTION
•
Combined DAC/Voltage
The UCC3880-4/-5/-6 combines high precision reference and voltage monitor-
ing circuitry with average current mode PWM controller circuitry to power Intel
Pentium Pro and other high-end microprocessors with a minimum of external
components. The UCC3880-x converts 5VDC to an adjustable output, ranging
from 2.0VDC to 3.5VDC in 100mV steps with 1% DC system accuracy.
Monitor and PWM Functions
•
4-Bit Digital-to-Analog
Converter (DAC)
•
•
1.0% DAC/Reference
The chip includes a precision 5V reference which is capable of sourcing cur-
rent to an external load. The output voltage of the DAC is derived from this
reference, and is programmed directly by Intel’s VID pins (Table 1).
Low Offset X20 Current Sense
Amplifier
The accuracy of the DAC/reference combination is 1.0%. The overvoltage and
undervoltage comparators monitor the system output voltage and indicate
when it rises above or falls below its programmed value by more than 7.5%. A
second overvoltage protection comparator pulls the current amplifier output
voltage low to force zero duty cycle when the system output voltage exceeds
its designed value by more than 15%. This comparator also terminates the cy-
cle. Undervoltage lockout circuitry assures the correct logic states at the out-
puts during powerup and powerdown. Grounding the ENABLE pin forces the
GATE output low.
•
100kHz, 200kHz, 400kHz
Oscillator Frequency Options
•
•
Foldback Current Limiting
Overvoltage and Undervoltage
Fault Windows
•
•
•
Undervoltage Lockout
2Ω Totem Pole Output
Chip Disable Function
(continued)
BLOCK DIAGRAM
UDG-96106-1
10/96
UCC2880-4/-5/-6
UCC3880-4/-5/-6
DESCRIPTION (cont.)
CONNECTION DIAGRAM
The voltage and current amplifiers have a 4MHz gain
bandwidth product to satisfy high performance system re-
quirements. The internal current sense amplifier permits
the use of a low value current sense resistor, minimizing
power loss. The oscillator frequency is fixed internally at
100kHz, 200kHz, or 400kHz, depending upon the option
selected. The foldback circuit reduces the converter short
circuit current limit to 50% of its nominal value when the
SOIC-20 (Top View)
DW Package
converter is short circuited. The gate driver is a 2Ω totem
pole output stage capable of driving an external MOSFET.
This device is available in 20-pin dual in-line and surface
mount packages. The UCC2880-x is specified for opera-
tion from –25°C to 85°C, and the UCC3880-x is specified
for operation from 0°C to 70°C.
Pentium® Pro is a registered trademark of Intel Corpora-
tion.
ORDERING INFORMATION
Frequency Gain Table
Frequency
200kHz
100kHz
X
400kHz
X
UCC3880-4
UCC3880-5
UCC3880-6
X
Consult factory for temperature range or package options
not shown.
ELECTRICAL CHARACTERISTICS: Unless otherwise specified, VIN = 12V, VSENSE = 3.5V, VENBL = 5V, VD0 = VD1 = VD2
= VD3 = 0V, 0°C < TA < 70°C, TA = TJ.
PARAMETER
Undervoltage Lockout
VIN UVLO Turn-on Threshold
VIN UVLO Turn-off Threshold
UVLO Threshold Hysteresis
Supply Current
TEST CONDITIONS
MIN
TYP
MAX UNITS
10.5
10
10.8
V
V
9.5
500
mV
lIN
3.5
mA
DAC/Reference
COMMAND Voltage Accuracy
D0-D3 Voltage High
D0-D3 Input Bias Current
VREF Output Voltage
VREF Load Regulation
VREF Sourcing Current
OVP Comparator
10.8V < VIN < 13.2V, IVREF = 0mA
DX Pin Floating
–1
1
%
V
5
–70
5
DX Pin Tied to GND
–20
µA
V
4.975
–10
5.025
IVREF = 0mA to 5mA
VREF = 0V
0
mV
mA
10
Trip Point
% Over COMMAND Voltage
OV, OVP, UV Combined
10
15
20
20
30
%
mV
µA
µs
Hysteresis
VSENSE Input Bias Current
Propagation Delay
–0.1
1
2
UCC2880-4/-5/-6
UCC3880-4/-5/-6
ELECTRICAL CHARACTERISTICS (cont.): Unless otherwise specified, VIN = 12V, VSENSE = 3.5V, VENBL = 5V, VD0 =
VD1 = VD2 = VD3 = 0V, 0°C < TA < 70°C, TA = TJ.
PARAMETER
OV Comparator
TEST CONDITIONS
MIN
TYP
MAX UNITS
Trip Point
% Over COMMAND Voltage (Note 1)
% Over COMMAND Voltage (Note 1)
7.6
7.4
20
10
%
%
Return Point
Hysteresis
5
30
mV
Ω
PWRGOOD Equivalent Resistance VSENSE = 2.0V
Propagation Delay
470
1
µs
UV Comparator
Trip Point
% Over COMMAND Voltage (Note 1)
% Over COMMAND Voltage (Note 1)
–10
–7.6
–7.4
20
%
%
Return Point
–5
30
Hysteresis
mV
µs
Propagation Delay
1
Enable Pin
Pull-up Current
VENBL = 2.5V
–50
–20
0
µA
Voltage Error Amplifier
Input Offset Voltage
Input Bias Current
VCOMP = 3.5V
0.0
–0.02
90
mV
µA
VCM = 3.0V
Open Loop Gain
1V < VCOMP < 4V
dB
Common Mode Rejection Ratio
Power Supply Rejection Ratio
Output Sourcing Current
Output Sinking Current
Gain Bandwidth Product
Current Sense Amplifier
Gain
2V < VCOMP < 3.5V
90
dB
10.8V < VIN < 15V
85
dB
VVFB = 2V, VCOMMAND = VCOMP = 2.5V
VVFB = 3V, VCOMMAND = VCOMP = 2.5V
F = 100kHz
–0.5
2.0
3
mA
mA
MHz
20
5
V/V
kΩ
Input Resistance
Common Mode Rejection Ratio
Power Supply Rejection Ratio
Output Sourcing Current
Output Sinking Current
–3dB Frequency
0V < VCM < 4.5V
60
dB
10.8V < VIN < 15V
80
dB
VIS– = 2V, VISOUT = VIS+ = 2.5V
VIS– = 3V, VISOUT = VIS+ = 2.5V
At GAIN = 20
–0.5
6.0
1.75
mA
mA
MHz
Current Amplifier
Input Offset Voltage
Input Bias Current
VCM = 3.0V
10
mV
µA
dB
VCM = 3.0V
0.15
90
Open Loop Gain
1V < VCAO < 3V
Output Voltage High
Common Mode Rejection Ratio
Power Supply Rejection Ratio
Output Sourcing Current
Output Sinking Current
Gain Bandwidth Product
VCOMP = 3V, VCAM = 2.5V
1.5V < VCM < 4.9V
10.8V < VIN < 15V
VCAM = 2V, VCAO = VCOMP = 2.5V
VCAM = 3V, VCAO = VCOMP = 2.5V
F = 100kHz
3.2
80
V
dB
80
dB
–0.5
2.0
3.5
mA
mA
MHz
3
UCC2880-4/-5/-6
UCC3880-4/-5/-6
ELECTRICAL CHARACTERISTICS (cont.): Unless otherwise specified, VIN = 12V, VSENSE = 3.5V, VENBL = 5V, VD0 =
VD1 = VD2 = VD3 = 0V, 0°C < TA < 70°C, TA = TJ.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX UNITS
Oscillator
Frequency (-4)
Frequency (-5)
85
100
200
400
1
115
99
kHz
kHz
kHz
%
Frequency (-6)
Frequency Change With Voltage
Output Section
Maximum Duty Cycle
Output Low Voltage
Output High Voltage
Rise Time
10.8V < VIN < 15V
90
95
0.20
11.8
20
%
V
IGATE = –100mA
IGATE = 100mA
CGATE = 3.3nF
CGATE = 3.3nF
IGATE = 100mA
IGATE = –100mA
V
80
80
ns
ns
Ω
Ω
Fall Time
15
Output Impedance
2
2
Foldback Current Limit
Clamp Level
Measured at Voltage EA Output;
VSENSE = VCOMMAND = 3V
4.4
3.7
V
V
VCOMMAND = 3V, VSENSE = 0
Note 1: This percentage is measured with respect to the ideal COMMAND voltage programmed by the D0 - D3 pins.
PIN DESCRIPTIONS (cont.)
CAM (Current Amplifier Inverting Input): The average
load current feedback from ISOUT is applied through a
resistor to this pin. The current loop compensation net-
work is also connected to this pin (see CAO below).
Decimal
Code
D3
D2
D1
D0
COMMAND
Voltage
15
14
13
12
11
10
9
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0
3.1
3.2
3.3
3.4
3.5
CAO (Current Amplifier Output): The current loop com-
pensation network is connected between this pin and
CAM. The voltage on this pin is the input to the PWM
comparator and regulates the output voltage of the sys-
tem. The GATE output is disabled (held low) unless the
voltage on this pin exceeds 1V, allowing the PWM to
force zero duty cycle when necessary. The PWM forces
maximum duty cycle when the voltage on CAO exceeds
the oscillator peak voltage (3V). A 3.2V clamp circuit pre-
vents the CAO voltage from rising excessively past the
oscillator peak voltage for excellent transient response.
8
7
6
5
4
3
2
COMMAND (Digital-to-Analog Converter Output Volt-
age): This pin is the output of the 4-bit digital-to-analog
converter (DAC) and the noninverting input of the voltage
amplifier. The voltage on this pin sets the switching regu-
lator output voltage. Setting all input control codes low
produces 3.5V at COMMAND; setting all codes high pro-
duces 2.0V at COMMAND. The DAC LSB step size (i.e.
resolution) is 100mV (See Table 1). The COMMAND
source impedance is typically 1.2kΩ and must therefore
drive only high impedance inputs if accuracy is to be
maintained. Bypass COMMAND with a 0.01µF, low ESR,
low ESL capacitor for best circuit noise immunity.
1
0
Table 1. Programming the COMMAND Voltage
COMP (Voltage Amplifier Output): The system voltage
compensation network is applied between COMP and
VFB.
D0 - D3 (DAC Digital Input Control Codes): These are
the DAC digital input control codes, with D0 representing
the least significant bit (LSB) and D3, the most significant
bit (MSB). A bit is set low by being connected to GND. A
4
UCC2880-4/-5/-6
UCC3880-4/-5/-6
PIN DESCRIPTIONS (cont.)
bit is set high by floating it, or connecting it to a 5V circuit board trace close to the IC. Decouple VIN to
source. Each control pin is pulled up to approximately 5V
PGND with a low ESR capacitor ≥ 0.10µF.
by an internal 70µA current source.
PWRGOOD (Undervoltage/Lower Overvoltage Out-
ENBL (Chip Enable Pin): This input is used to disable put): This pin is an open drain output which is driven low
the GATE and PWRGOOD outputs. Grounding this pin to reset the microprocessor when VSENSE rises above
causes the GATE output to be held low; floating the pin or or falls below its nominal value by 7.5%. The on resis-
pulling it up to 5V ensures normal operation. ENBL is tance of the open drain switch will be no higher than
pulled up to 5V internally.
470Ω. The OV and UV comparators’ hysteresis is fixed at
20mV independent of the COMMAND voltage.
GATE (PWM Output, MOSFET Driver): This output pro-
vides a 2Ω totem pole driver. Use a series resistor of at VIN (Positive Supply Voltage): This pin supplies power
to the chip. Connect VIN to a stable voltage source of at
least 10.8V. The GATE and PWRGOOD outputs will be
held low until VCC exceeds the upper undervoltage lock-
out threshold. This pin should be bypassed directly to the
GND pin.
least 5Ω between this pin and the gate of the external
MOSFET to prevent excessive overshoot.
GND (Signal Ground): All voltages are measured with
respect to GND. Bypass capacitors on the VCC and
VREF pins should be connected directly to the ground
plane near the GND pin.
VFB (Voltage Amplifier Inverting Input): This input is
connected to COMP through a feedback network and to
the power supply output through a resistor or a divider
network.
IS– (Current Sense Amplifier Inverting Input): This pin
is the inverting input to the current sense amplifier and is
connected to the low side of the average current sense
resistor.
VREF (Voltage Reference Output): This pin provides an
accurate 5V reference and is internally short circuit cur-
rent limited. VREF powers the D/A converter and also
provides a threshold voltage for the UVLO comparator.
For best reference stability, bypass VREF directly to GND
with a low ESR, low ESL capacitor of at least 0.01µF.
IS+ (Current Sense Amplifier Noninverting Input):
This pin is the noninverting input to the current sense am-
plifier and is connected to the high side of the average
current sense resistor.
ISOUT (Current Sense Amplifier Output): This pin is
the output of the current sense amplifier. The voltage on
this pin is (COMMAND + GCSA • I • RSENSE), where
COMMAND is the voltage on the COMMAND pin, GCSA
is the fixed gain of the current sense amplifier, equal to
20, I is the current through the sense resistor, and
RSENSE is the value of the average current sensing resis-
tor.
VSENSE (Output Voltage Sensing Input): This pin is
connected to the system output voltage through a low
pass filter. When the voltage on VSENSE rises above or
falls below the COMMAND voltage by 7.5%, the
PWRGOOD output is driven low to reset the microproc-
essor. When the voltage on VSENSE rises above the
COMMAND voltage by 15%, the OVP comparator pulls
the current amplifier output voltage below the oscillator
valley voltage to force zero duty cycle at the GATE out-
put. This pin is also used by the foldback current limiting
circuitry.
PGND (Power Ground): This pin provides a dedicated
ground for the output gate driver. The GND and PGND
pins should be connected externally using a short printed
APPLICATION INFORMATION
Current Limit
1.4V
16A • 20
RSENSE =
= 4.4mΩ
The short circuit current limit, ISC, is set according to:
A lower resistance value may be needed if the AC ripple
current in the inductor is more than 20% of the full load
current.
1.4V
ISC =
RSENSE • GCSA
where RSENSE is the average current sense resistor and
GCSA is the current sense amplifier gain, where GCSA
Related Publications
equals 20. Example: Choose RSENSE to set the short cir- U-156 and U-157 are Unitrode Application Notes describ-
cuit current limit at 16A using the UCC3880-5
ing the operation of the UC3886 and the UC3886/
UC3910 together in a Pentium® Pro application.
5
UCC2880-4/-5/-6
UCC3880-4/-5/-6
TYPICAL APPLICATION
The UCC3880-x is ideal for converting the 5.0V system bus into the required Pentium® Pro bus voltage.
UDG-96224
UCC3880 Configured for Powering the Pentium® Pro
6
UCC2880-4/-5/-6
UCC3880-4/-5/-6
PARTS LIST
REF.
U1
DESCRIPTION
PACKAGE
SOIC-20 Wide
10x20mm Radial Can
10x20mm Radial Can
10x20mm Radial Can
10x20mm Radial Can
SPRAGUE Size A
10x20mm Radial Can
10x20mm Radial Can
10x20mm Radial Can
10x20mm Radial Can
10x20mm Radial Can
EIA Size D SMD
1206 SMD
Unitrode UCC3830DWP-5 DAC/PWM
Sanyo 6MV1500GX, 1500µF, 6.3V, Aluminum Electrolytic
Sanyo 6MV1500GX, 1500µF, 6.3V, Aluminum Electrolytic
Sanyo 6MV1500GX, 1500µF, 6.3V, Aluminum Electrolytic
Sanyo 6MV1500GX, 1500µF, 6.3V, Aluminum Electrolytic
Sprague/Vishay 595D475X0016A2B, 4.7µF 16V Tantalum
Sanyo 6MV1500GX, 1500µF, 6.3V, Aluminum Electrolytic
Sanyo 6MV1500GX, 1500µF, 6.3V, Aluminum Electrolytic
Sanyo 6MV1500GX, 1500µF, 6.3V, Aluminum Electrolytic
Sanyo 6MV1500GX, 1500µF, 6.3V, Aluminum Electrolytic
Sanyo 6MV1500GX, 1500µF, 6.3V, Aluminum Electrolytic
Sprague 593D107X9010D2, 100µF, 6.3V Tantalum
0.10µF Ceramic
C1
C2
C3
C4
C5
C6
C7
C8
C9
C10
C11
C12
C13
C14
C15
C16
C17
C18
C19
C20
C21
C22
CR1
L1
0.01µF Ceramic
0603 SMD
0.01µF Ceramic
0603 SMD
0.01µF Ceramic
0603 SMD
1000pF Ceramic
0603 SMD
0.10µF Ceramic
1206 SMD
33pF NPO Ceramic
0603 SMD
1500pF Ceramic
0603 SMD
82pF NPO Ceramic
0603 SMD
0.10µF Ceramic
1206 SMD
0.10µF Ceramic
1206 SMD
International Rectifier 32CTQ030 30V, 30A Schottky Diode
Micrometals T50-52B, 10 Turns #16AWG, 4.5µH
International Rectifier IRL3103, 30V, 56A
Dale/Vishay WSR-2 0.005Ω 1%
10Ω, 5%, 1/16 Watt
TO-220AB
Toroid
Q1
TO-220AB
R1
SMD Power Package
0603 SMD
R2
R3
8.2kΩ, 5%, 1/16 Watt
0603 SMD
R4
6.81kΩ, 1%, 1/16 Watt
0603 SMD
R5
3.92kΩ, 1%, 1/16 Watt
0603 SMD
R6
261kΩ, 1%, 1/16 Watt
0603 SMD
R7
100kΩ, 1%, 1/16 Watt
0603 SMD
R8
3.92kΩ, 1%, 1/16 Watt
0603 SMD
R9
10.5kΩ, 1%, 1/16 Watt
0603 SMD
Q1-HS
CR1-HS
AAVID 576802 TO-220 Heat Sink
AAVID 577002 TO-220 Heat Sink
TO-220AB
TO-220AB
Pentium® Pro is a registered trademark of Intel Corporation.
UNITRODE INTEGRATED CIRCUITS
7 CONTINENTAL BLVD. • MERRIMACK, NH 03054
TEL. (603) 424-2410
• FAX (603) 424-3460
7
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