®
SP6122
Low Voltage, Micro 8, PFET, Buck Controller
Ideal for 1A to 5A, Small Footprint, DC-DC Power Converters
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Optimized for Single Supply, 3V-5.5V Applications
High Efficiency, Greater than 90% Possible
8
PDRV
VCC
1
20ns/1nF PFET Output Driver
SP6122
FFLAG
2
7
GND
8 Pin MSOP
Fast Transient Response
VOUT
3
6
ISET
Open Drain Fault Output Pin
ENABLE
4
5
ISENSE
Internal Soft Start Circuit
Accurate 1.5% Reference
Programmable Output Voltage or Fixed 1.5V Output
Now Available in Lead Free Packaging
Loss-less Adjustable Current Limit with High side
R
DS(ON)
Sensing
Hiccup or Lock-up Fault Modes
Low 5µA Sleep Mode Quiescent Current
APPLICATIONS
Low 300µA Protected Mode Quiescent Current
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Video Cards
Ultra Low, 150µA Unprotected Mode Quiescent
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High Power Portable
Current
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Microcontrollers
High Light Load Efficiency
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I/O & Logic
Offered in Tiny 8 pin MSOP Package
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Industrial Control
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Distributed Power
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Low Voltage Power
DESCRIPTION
The
SP6122
is a PWM/PFM minimum on-time controller designed to work from a single 3V-
5.5V input supply. It is engineered specifically for size and minimum component count,
simplifying the transition from a linear regulator to a switcher solution. However, unlike other
“micro” parts, the
SP6122
has an array of value added features such as optional hiccup
mode, over current protection, TTL enable, “jitter and frequency stabilization” and a fault flag
pull-down pin. Combined with reference and driver specifications usually found on more
expensive integrated circuits, the
SP6122
delivers great performance and value in an 8 pin
MSOP package.
TYPICAL APPLICATION CIRCUIT
R1
C1
4.7µF
V
CC
V
IN
C2
100µF
PDRV
®
3.0V to 7.0V
5Ω
R
SET
1k
Q1
PDS6375
FFLAG
FFLAG
V
OUT
GND
SP6122
I
SET
I
SENSE
ENABLE
ENABLE
L1
2.2µH
STPS2L25U
DFLY
1A to 5A
V
OUT
C
OUT
470µF
Date: 10/02/04
SP6122 Low Voltage, Micro 8, PFET, Buck Controller
© Copyright 2004 Sipex Corporation
1
ABSOLUTE MAXIMUM RATINGS
These are stress ratings only and functional operation of
the device at these ratings or any other above those
indicated in the operation sections of the specifications
below is not implied. Exposure to absolute maximum
rating conditions for extended periods of time may affect
reliability.
V
CC ..............................................................................................................
7V
All other pins ...................................... -0.3V to V
CC
+0.3V
Peak Output Current < 10µs
PDRV ......................................................................... 2A
Storage Temperature .............................. -65°C to 150°C
Power Dissipation
Lead Temperature (Soldering, 10 sec) ................. 300°C
ESD Rating ...................................................... 2kV HBM
ELECTRICAL CHARACTERISTICS
Unless otherwise specified: 0°C < T
AMB
< 70°C, 3.0V < V
CC
< 5.5V, C
PDRV
= 1nF, V
ENABLE
= V
CC
, V
FFLAG
= V
CC
,
I
SET
= I
SENSE
= V
CC
, GND = 0.0V
PARAMETER
QUIESCENT CURRENT
V
CC
Supply Current,
OVC Enabled
V
CC
Supply Current,
OVC Disabled
V
CC
Supply Current,
OVC Disabled, Ultra Low IQ
V
CC
Supply Current, Sleep Mode
REFERENCE
Output Voltage, Initial Accuracy
Output Voltage, Over Line,
Load and Temperature
Reference Comparator
Hysteresis
V
OUT
Input Current
MIN
TYP
MAX
UNITS
CONDITIONS
-
-
-
-
300
250
150
5
450
360
225
15
µA
µA
µA
µA
No Switching, I
SET
= I
SENSE
= V
CC
No Switching, I
SET
= I
SENSE
= 0
No Switching, ISET = 0,
I
SENSE
=V
CC
Enable=0
VR*0.985
VR*0.980
-
-
VR
VR
5
23
VR*1.015
VR*1.020
-
-
V
V
mV
µA
VR = Factory Set Voltage,
see Note
VR = Factory Set Voltage,
see Note
Internal Hysteresis at Feedback
Terminal
V
OUT
= VR;
SP6122ACU-1.5 ONLY
OSCILLATOR
Oscillator Frequency
Minimum Pulse Width during
Startup (Blanking Time)
Soft Start
Soft Start Ramp Time
-
3.5
-
ms
V
OUT
= VR – 30mV, Measure
time from ENABLE = 1V to
PDRV Low
Measure VSoft Start when
PDRV goes Low. (internal)
210
150
300
270
390
380
kHz
ns
Soft Start Voltage when
PDRV Switches
-
250
-
mV
Date: 10/02/04
SP6122 Low Voltage, Micro 8, PFET, Buck Controller
© Copyright 2004 Sipex Corporation
2
ELECTRICAL CHARACTERISTICS
Unless otherwise specified: 0°C < T
AMB
< 70°C, 3.0V < V
CC
< 5.5V, C
PDRV
= 1nF, V
ENABLE
= V
CC
, V
FFLAG
= V
CC
,
I
SET
= I
SENSE
= V
CC
, GND = 0V
PARAMETER
MIN
TYP
MAX
UNITS
CONDITIONS
RDS OVER CURRENT COMPARATOR
Over Current Comparator
Threshold Voltage
Threshold Voltage Temperature
Coefficient
I
SET
Sink Current
I
SET
Current Temperature
Coefficient
I
SENSE
Input Bias Current
I
SET
, I
SENSE
Common Mode
Input Range
Over Current Peak Detection
Time Constant
ENABLE INPUT & FFLAG OUTPUT
ENABLE Threshold
ENABLE Pin Source Current
FFLAG Sink Current
GATE DRIVER
PDRV Rise Time
PDRV Fall Time
20
20
75
75
ns
ns
0.5V to 4.5V
4.5V to 0.5V
0.90
0.8
3.0
1.21
5.0
7.5
1.45
10.0
15.0
V
µA
mA
V(FFLAG) = 1V
130
-
15
-
-
2.0
-
150
3800
20
4300
-
-
10
180
-
25
-
100
V
CC
-
mV
ppm/°C
µA
ppm/°C
nA
V
µs
Current into I
SET
25°C only
V(I
SET
) - V(I
SENSE
) 25°C only
NOTE: Available Output Voltages: 1.5V Fixed, 1.25V Adj.
Date: 10/02/04
SP6122 Low Voltage, Micro 8, PFET, Buck Controller
© Copyright 2004 Sipex Corporation
3
PIN DESCRIPTION
PIN #
1
2
3
4
PIN NAME
V
CC
FFLAG
V
OUT
ENABLE
DESCRIPTION
Main Supply Pin: A RC filter as shown in the application circuit is
recommended. The decoupling capacitor needs to be close to the pin.
Fault Flag Pull-down Pin: Sinks current during a fault condition. Can
be hooked up to ENABLE to initiate Hiccup Timing.
Regulated Output Voltage: This voltage is divided internally and
compared to a 1.5%, 1.25V reference at the PFM comparator.
Enable Input: Floating this pin or pulling above 1.45V enables the
part. Pulling this pin to less than 0.9V will disable the part. A minimum
100pF capacitor is required between this pin and Ground to ensure
proper startup. If FFLAG is hooked to ENABLE, the capacitor on
ENABLE will control hiccup timing.
Negative Input to the Over Current Amplifier/Comparator: This input
is subtracted from the I
SET
input and gained by a factor of 3.3. The
output of this amplifier is compared with a 0.5V threshold, yielding a
150mV threshold. This threshold has a 3800 ppm/°C temperature
coefficient. If the subtraction exceeds 150mV, charge is pumped into
a capacitor until the capacitor hits V
CC
/2. At this time, the over current
fault is activated. If I
SET
= 0V and I
SENSE
= V
CC
, the part enters an
unprotected, 150µA quiescent current mode.
Positive Input to the Over Current Amplifier: 20µA flows into the I
SET
pin if it is pulled through a resistor to V
IN
. This current has a
4300ppm/°C temperature coefficient and can be used via external
resistor to raise the overcurrent trip point from 150mV to some higher
value. If I
SET
= 0V and I
SENSE
= 0V, the part enters an unprotected,
250µA quiescent current mode.
Power and Analog Ground: Hook directly to output ground.
Drive for PFET High Side Switch: 1nF/20ns Output Driver.
5
I
SENSE
6
I
SET
7
8
GND
PDRV
Date: 10/02/04
SP6122 Low Voltage, Micro 8, PFET, Buck Controller
© Copyright 2004 Sipex Corporation
4
BLOCK DIAGRAM
Soft Start
SS
-
+
Reset
Dominant
R
SS
Latch
S
QB
PFET OFF
ENABLE 4
1.25V
Reference
-
+
1V
Reset
Dominant
POR R
QB
Run
Latch
S
Q
Soft Start Clock
V
OUT
* K1
T
ON
Min On Time Clock
RESET
Dominant
S
QB
Loop
Latch
R
Q
PFET OFF
7 GND
Blank
Start On Time
1 V
CC
Reference
Comparator
Driver
Logic
PFET
Driver
8 PDRV
-
V
OUT
3
X K1
+
I
SET
6
20µA
(4300 ppm/°C)
PDRV
Over Current
(Gated S&H)
200ns Blanking
One Shot
+
X 3.3
I
SENSE
5
+
-
POR
Reset
Dominant
S
Q FAULT
R
POR
2 FFLAG
-
500mV
(3800 ppm/°C)
I
SET
I
SENSE
I
SET
< 1V
Low IQ
Date: 10/02/04
SP6122 Low Voltage, Micro 8, PFET, Buck Controller
© Copyright 2004 Sipex Corporation
5
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