IR3087
DATA SHEET
XPHASE
TM
PHASE IC WITH OPTI-PHASE
TM
, OVP, AND OVERTEMP DETECT
DESCRIPTION
The IR3087 Phase IC combined with an IR XPhase
TM
Control IC provides a full featured and flexible way to
implement power solutions for the latest high performance CPUs and ASICs. The "Control" IC provides
overall system control and interfaces with any number of "Phase" ICs which each drive and monitor a single
phase of a multiphase converter. The XPhase
TM
architecture results in a power supply that is smaller, less
expensive, and easier to design while providing higher efficiency than conventional approaches.
The IR3087 with Opti-Phase
TM
is intended for applications demanding increased efficiency under medium to
light load conditions. Both gate drivers will drive low at a programmable output current threshold. This
effectively disconnects the phase from the load eliminating power losses due to switching and circulating
currents.
FEATURES
2.5A Average Gate Drive Current
Loss-Less Inductor Current Sense
Internal Inductor DCR Temperature Compensation
Programmable
Phase
Delay
Programmable Feed-Forward Voltage Mode PWM Ramp
Sub 100ns Minimum Pulse Width supports 1MHz per-phase operation
Current Sense Amplifier drives a single wire Average Current Share Bus
Current Share Amplifier reduces PWM Ramp slope to ensure sharing between phases
Body Braking
TM
disables Synchronous MOSFET for improved transient response and prevents negative
output voltage at converter turn-off
Opti-Phase
TM
reduces the number of phases for improved light to medium load efficiency
OVP comparator with 150ns response
Programmable Phase Over-Temperature Detection
Small thermally enhanced 20L MLPQ package
APPLICATION CIRCUIT
R
P
H
ASE
2
RCS+
CCS-
CVCC
L
RP
HA
S
E
3
CVCCL
CSCOMP
20k
RBIASIN
DBST
RP
HA
S
E
1
CCS+
RVCC
RPWMRMP
CIN
RCS-
CP
WMRM
P
CBST
VO
RAMP
BIAS
DAC
VRHOT
EA
ISHARE
12V
CO
VGATE
5 Wire Analog Bus
From Control IC
DA
CI
N
19
BI
AS
I
N
20
RMPIN+
1
RMPIN-
2
GATEH
14
VCCH
15
CS
I
N
-
17
OP
T
I
PH
S
18
HOTSET
3
VRHOT
4
SC
OM
P
6
EAI
N
7
PGND
13
GATEL
12
LGN
D
9
P
W
MRMP
8
ISHARE
5
VC
C
10
VCCL
11
CS
IN+
16
IR3087
PHASE
IC
ROP1
ROP2
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/31/05
IR3087
ELECTRICAL SPECIFICATIONS
Unless otherwise specified, these specifications apply over: 8.4V
V
CC
21V, 6V
V
CCH
28V, 6V
V
CCL
14V, and 0
o
C
T
J
125
o
C, C
GATEH
= 3.3nF, C
GATEL
= 6.8nF
PARAMETER TEST
CONDITION
MIN
TYP
MAX
UNIT
Gate Drivers
GATEH Rise Time
VCCH = 12V, Measure 2V to 9V
transition time
22
50 ns
GATEH Fall Time
VCCH = 12V, Measure 9V to 2V
transition time
22
50 ns
GATEL Rise Time
VCCL = 12V, Measure 2V to 9V
transition time
50
75 ns
GATEL Fall Time
VCCL = 12V, Measure 9V to 2V
transition time
50
75 ns
GATEL low to GATEH high
delay
VCCH = VCCL = 12V, Measure the time
from GATEL falling to 1V to GATEH
rising to 1V
10 25 50 ns
GATEH low to GATEL high
delay
VCCH = VCCL = 12V, Measure the time
from GATEH falling to 1V to GATEL
rising to 1V
10 25 50 ns
Disable Pull-Down Current
Force GATEH or GATEL = 2V with
BIASIN = 0V
15 25 40
A
Current Sense Amplifier
CSIN+ Bias Current
-0.5
-0.25
0
A
CSIN- Bias Current
-1
-0.4
0
A
Input Offset Voltage
CSIN+ = CSIN- = DACIN. Measure
input referred offset from DACIN
-3 0.5 5 mV
Gain at T
J
= 25
o
C
32
34
36
V/V
Gain at T
J
= 125
o
C
27
29
31
V/V
Slew Rate
Current Sense Amplifier output is an
internal node. Slew rate at the ISHARE
pin will be set by the internal 10k
resistor and any stray external
capacitance
12.5 V/
s
Differential Input Range
-20
100
mV
Common Mode Input Range
0
4
V
Rout at T
J
= 25
o
C
7.9
10.5
13.1
k
Rout at T
J
= 125
o
C
9.3
12.4
15.5
k
Ramp Discharge Clamp
Clamp Voltage
Force I(PWMRMP) = 500
A. Measure
V(PWMRMP) V(DACIN)
-10 5 20 mV
Clamp Discharge Current
4
8
mA
Page 3 of 35
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/31/05
IR3087
PARAMETER TEST
CONDITION
MIN
TYP
MAX
UNIT
Ramp Comparator
Input Offset Voltage
20
40
80
mV
Hysteresis
Note 1
-10
0
10
mV
RMPIN+, RMPIN- Bias
Current
-1
0
1
A
Propagation Delay
VCCH = 12V. Measure time from
RMPIN input (50mV overdrive) to
GATEL transition to <11V.
100 150 240 ns
PWM Comparator
PWM Comparator Input Offset
Voltage
-5
5
15
mV
EAIN & PWMRMP Bias
Current
Clamp and Current Share Adjust OFF
-1
-0.4
1
A
Propagation Delay
VCCH = 12V. Measure time from
PWMRMP input (50mV overdrive) to
GATEH transition to < 11V.
70
150
ns
Common Mode Input Range
Exceeding the Common Mode input
range results in 100% duty cycle
5
V
Share Adjust Error Amplifier
Input Offset Voltage
10
20
30
mV
Input Voltage Range
EAIN PWMRMP, Note 1
-3.5
3.5
V
PWMRMP Adjust Current
4
8
mA
Transconductance I(PWMRMP)
=
3.5mA, Note 1
0.9
1.6
2.3
A/V
SCOMP Source/Sink Current
Note 1
20
30
40
A
SCOMP Activation Voltage
Amount SCOMP must increase from its
minimum voltage until the Ramp Slope
Adjust current equals = 10
A
60 150 300 mV
PWMRMP Min Voltage
I(PWMRMP) = 500
A
150 225 350 mV
0% Duty Cycle Comparator
Threshold Voltage
Compare to V(DACIN)
86
88
92
%
Propagation Delay
VCCL = 12V. Measure time from EAIN
< 0.9 x V(DACIN) (200mV overdrive) to
GATEL transition to < 11V. Note 1.
100
150 ns
Opti-Phase
TM
Comparator
Threshold Voltage
VDACIN = 0.8V, V(OPTIPHS) = 0.25V
-5
35
75
mV
Threshold Voltage
VDACIN = 0.8V, V(OPTIPHS) = 1.0V
-55
10
90
mV
Threshold Voltage
VDACIN = 0.8V, V(OPTIPHS) = 2.0V
-135
-25
105
mV
Threshold Voltage
VDACIN = 1.2V, V(OPTIPHS) = 0.25V
-10
45
90
mV
Threshold Voltage
VDACIN = 1.2V, V(OPTIPHS) = 1.0V
-55
25
105
mV
Threshold Voltage
VDACIN = 1.2V, V(OPTIPHS) = 2.0V
-130
0
135
mV
Threshold Voltage
VDACIN = 1.6V, V(OPTIPHS) = 0.25V
-15
50
115
mV
Threshold Voltage
VDACIN = 1.6V, V(OPTIPHS) = 1.0V
-50
40
120
mV
Threshold Voltage
VDACIN = 1.6V, V(OPTIPHS) = 2.0V
-125
10
155
mV
Propagation Delay
200
ns
OPTIPHS Bias Current
-1
-0.2
1
A
Disable Comparator Threshold V(BIASIN) V(OPTIPHS)
100
400
750
mV
Page 4 of 35
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/31/05
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