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CALIFORNIA MICRO DEVICES
CMPWR101
250mA SmartORTM Regulator with VAUX Switch
Features
* Automatic detection of V CC input supply * Glitch-free output during supply transitions * Built-in hysteresis during supply selection * 250mA output maximum load current * Fully integrated VAUX switch * Overload current protection * Short circuit current protection * Operates from either VCC or V AUX * 8-pin SOIC package
Applications
* PCI adapter cards * Network Interface Cards (NIC's) * Dual power systems * Systems with standby capabilities
Product Description
The California Micro Devices' SmartORTM CMPWR101 is a low dropout regulator that delivers up to 250mA of load current at a fixed 3.3V output. An internal threshold level (typically 4.1V) is used to prevent the regulator from being operated below dropout voltage. The device continuously monitors the input supply and will automatically disable the regulator when VCC falls below the threshold level. When the regulator is disabled, a low impedance, fully integrated switch is enabled which allows the output to be directly powered from an auxiliary 3.3V supply. When VCC is restored to a level above the select threshold, the low impedance switch is disabled and the regulator is once again enabled. All the necessary control circuitry needed to provide a smooth and automatic transition between the supplies has been incorporated. This allows VCC to be dynamically switched without loss of output voltage. An output logic signal, DRIVE, is active LOW whenever the internal regulator is disabled.
PIN DIAGRAM AND APPLICATION CIRCUIT
Top View VCC VAUX VAUX GND 1 2 3 4 8 7 6 5 DRIVE VOUT VOUT NC
+
CMPWR101 VCC CIN 1F
+
DRIVE
VOUT 3.3V 250mA
VCC 5V +
-
VAUX VOUT GND VAUX - 3.3V
+
COUT 4F GND
CMPWR101 8-Pin SOIC
Pin Diagram
Typical Application Circuit
STANDARD PART ORDERING INFORMATION
Package Pins 8 Style SOIC Ordering Part Number Tubes Tape & Reel CMPWR101S/T CMPWR101S/R Part Marking CMPWR101S
(c) 2001 California Micro Devices Corp. All rights reserved. SmartORTM is a trademark of California Micro Devices Corporation.
C1660101
215 Topaz Street, Milpitas, California 95035
3/6/2001
Tel: (408) 263-3214
Fax: (408) 263-7846
www.calmicro.com
1
CALIFORNIA MICRO DEVICES
ABSOLUTE MAXIMUM RATINGS
Parameter ESD Protection (HBM) VCC, VOUT Voltages Drive Logic Voltage VAUX Input Voltage Temperature: Storage Operating Ambient Operating Junction Power Dissipation (Note 1) Rating 2000 6.0, GND -0.5 V CC + 0.5, GND -0.5 4.0, GND -0.5 -40 to 150 0 to 70 0 to 125 0.5 Unit V V V V C C C W
CMPWR101
OPERATING CONDITIONS
Parameter VCC VAUX Temperature (Ambient) Load Current CEXT Range 5 0.5 3.3 0.3 0 to 70 0 to 250 4.7 20% Unit V V
C
mA F
ELECTRICAL OPERATING CHARACTERISTICS
(over operating conditions unless specified otherwise) Symbol VOUT ILIM VCCSEL VCCDES VCCHYST VR LOAD VR LINE RSWITCH IRCC IRAUX IGND Parameter Regulator Output Voltage Regulator Current Limit Select Voltage Deselect Voltage Hysteresis Voltage (Note 2) Load Regulation Line Regulation Auxiliary Switch Resistance VCC Pin Reverse Leakage VAUX Pin Reverse Leakage Ground Current Regulator Enabled Regulator Disabled Hysteresis VCC = 5V, ILOAD = 5 to 250mA VCC = 4.5V to 5.5V, ILOAD = 5mA VCCDES > VCC, VAUX = 3.3V VAUX = 3.3V, VCC = 0V VAUX = 0V, VCC = 5V VCC < VCCDES, ILOAD = 0mA VCC > VCCSEL, ILOAD = 0mA VCC > VCCSEL, ILOAD = 250mA IAUX ROH ROL VAUX Supply Current Drive Pull-up Resistance Drive Pull-down Resistance VAUX > VCC VCC > VAUX RPULLUP to VCC, VCC > VCCSEL RPULLDOWN to GND, VCCDES > VCC 3.90 Conditions 0mA < ILOAD < 250mA MIN 3.135 275 4.30 4.10 0.20 20 2 0.25 2 2 0.2 0.6 0.7 0.2 0.02 4.0 0.1 0.4 50 50 0.4 1.0 1.2 0.4 0.1 8.0 0.4 4.45 TYP 3.30 MAX 3.465 UNIT V mA V V V mV mV A A mA mA mA mA mA k k
Note 1: The power rating is based on a printed circuit board heat spreading capability equivalent to 2 square inches of copper connected to the GND pins. Typical multi-layer boards using power plane construction will provide this heat spreading ability without the need for additional dedicated copper area. (Please consult with factory for thermal evaluation assistance). Note 2: The hysteresis defines the maximum level of acceptable disturbance on VCC during switching. It is recommended that the VCC source impedance be kept below 0.25 to ensure the switching disturbance remains below the hysteresis during select/deselect transitions. An input capacitor may be required to help minimize the switching transient.
(c)2001 California Micro Devices Corp. All rights reserved. SmartORTM is a trademark of California Micro Devices Corporation.
2
215 Topaz Street, Milpitas, California 95035
Tel: (408) 263-3214
Fax: (408) 263-7846
www.calmicro.com
3/6/2001
CALIFORNIA MICRO DEVICES
Interface Signals
VCC is the power source for the internal regulator and is monitored continuously by an internal controller circuit. Whenever VCC exceeds VCCSEL (4.25V typically), the internal regulator will be enabled and deliver a fixed 3.3V at VOUT. When VCC falls below VCCDES (4.10V typically), the regulator will be disabled. Internal loading on this pin is typically 0.6mA when the regulator is enabled, which reduces to 0.1mA whenever the regulator is disabled. If VCC falls below the voltage on the VAUX pin, the VCC loading will further reduce to only a few microamperes. During a VCC power-up or power-down sequence, there will be an effective step increase in VCC line current when the regulator is enabled/disabled. This line current transient will cause a voltage disturbance at the VCC pin. The magnitude of the disturbance will be directly proportional to the effective power supply source impedance being delivered to the VCC input. A built-in hysteresis voltage of 150mV has been incorporated to minimize any chatter during supply changeover. It is recommended that the power supply connected to the VCC input should have a source resistance of less than 0.25 to minimize the event of chatter during the enabling/disabling of the regulator. If the VCC pin is within a few inches of the main input filter, a capacitor may not be necessary. Otherwise an input filter capacitor in the range of 1F to 10F will help to lower the effective source impedance.
CMPWR101
VAUX is the auxiliary power source. When selected, (VCC < VCCDES), the auxiliary supply is directly connected to VOUT, via the low impedance (0.3 typically) fully integrated switch. The internal loading on this pin is typically less than 10A and will increase to 100A if VCC falls below the voltage on VAUX. When VAUX = 0V, the VCCDES voltage is inhibited which prevents the regulator from being disabled. VOUT is the regulator output voltage connection used to power the load. An output capacitor of 4.7F is used to provide the necessary phase compensation, thereby preventing oscillation. The capacitor also helps to minimize the peak output disturbance during power supply changeover. DRIVE is a CMOS output logic signal (Active Low) referenced to the VCC supply. This output is taken low whenever the internal regulator is not enabled. This output is intended only as a control signal for external circuitry. GND is the negative reference for all voltages. The current that flows in the ground connection is very low (typically 0.6mA) and has minimal variation over all load conditions. NC is an unconnected pin which is electrically isolated from the internal circuitry.
PIN FUNCTIONS
Pin 1 2, 3 6, 7 8 4 5 Symbol VCC VAUX VOUT DRIVE GND NC Description Positive (5V) supply input for regulator. (VCC > VCCSEL) Auxiliary supply input is connected directly to the output via a low impedance when the regulator is disabled. Continuous output voltage (3.3V) is derived from either the internal regulator or low impedance switch connected to the auxiliary supply input. Output Control Signal which is taken LOW whenever VCC is unavailable Negative reference for all voltages Unconnected pin which is electrically isolated from internal circuitry.
VCC
+ -
DRIVE
VDESELECT 4.1V 0.2 VAUX 3.3V GND VREF 3.3V
+ -
ENABLE VOUT 3.3V 250mA
Simplified Electrical Schematic
(c) 2001 California Micro Devices Corp. All rights reserved. SmartORTM is a trademark of California Micro Devices Corporation.
215 Topaz Street, Milpitas, California 95035
3/6/2001
Tel: (408) 263-3214
Fax: (408) 263-7846
www.calmicro.com
3
CALIFORNIA MICRO DEVICES
Typical DC Characteristics (nominal conditions unless specified otherwise)
CMPWR101
0.8 0.7
0.34 0.32
Resistance ()
VCC Supply Current (A)
0.6 0.5 0.4 0.3 0.2 0.1 0.0 0 1 2 3 4 5 6 VCC Supply Voltage (V)
0.30 0.28 0.26 0.24 0.22 0.20 2.7
3.0
3.3
3.6
Auxiliary Supply Voltage (V)
Figure 1. Supply Current vs Voltage (VAUX = 3.3V)
Figure 2. Switch Resistance vs Supply Voltage
0.8 0.7
3.40 3.35
Ground Current (mA)
0.6 0.5 0.4 0.3 0.2 0.1 0.0 0 100 200 Load Current (mA) 300
Regulator Output (V)
5mA Load 3.30 3.25 3.20 3.15 3.10 3.0 250mA Load
3.5
4.0
4.5
5.0
5.5
Supply Voltage (V)
Figure 3. Ground Current vs Output Load
Figure 4. Line Regulation (1% and 100% rated load)
3.33 3.32 3.31
VOUT (V)
1.2 1.0 0.8
VOUT (V)
0 100 200 Load Current (mA) 300 400
3.30 3.29 3.28 3.27 3.26 3.25
0.6 0.4 0.2 0.0 0 100 200 Load Current (mA) 300 400
Figure 5. Load Regulation
215 Topaz Street, Milpitas, California 95035
Figure 6. Dropout Voltage with Load Current
Tel: (408) 263-3214 Fax: (408) 263-7846 www.calmicro.com
3/6/2001
(c)2001 California Micro Devices Corp. All rights reserved. SmartORTM is a trademark of California Micro Devices Corporation.
4
CALIFORNIA MICRO DEVICES
Typical Transient Characteristics (Supply source resistance set to 0.2)
Tek Run: 25kS/s Sample Tek Run: 25kS/s Sample
CMPWR101
Drive Drive 3 VCC VOUT VOUT 3 VCC
(200mA Load) (VAUX = 0V)
(200mA Load) (VAUX = 0V) Ch2 M 2ms Ch1 4.66V
Ch3
1V 5V
Ch2
1V
M 2ms Ch1
500mV
Ch3
1V 5V
1V
Figure 7. VCC Cold start Power Up (VAUX = 0V)
Tek 2.5MS/s 1 Acqs
Figure 8. VCC Complete Power Down (VAUX = 0V)
Tek 2.5MS/s 1 Acqs
Drive 3
3
Drive
VCC (offset = 4.3V) 2
2
VCC (offset = 4.3V)
VOUT (offset = 3.3V)
VOUT (offset = 3.3V)
Ch3
100mV 5V
Ch2 100mV M 20s Ch1
2.5V
Ch3
100mV 5V
Ch2 100mV M 20s Ch3
2.5V
Figure 9. VCC Power up (VAUX = 3.3V)
Tek 5MS/s 3 Acqs
Figure 10. VCC Power Down (VAUX = 3.3V)
Tek 1MS/s VCC (offset = 5.0V) 1V Step(4.5V to 5.5V) 2 1 Acqs
25mA to 225mA Load Step 2
VCC (offset = 3.3V)
VOUT (offset = 3.3V) (5mA Load)
20mV Ch2 2V M 20s Ch2 2.08V
20mV
Ch2 500mV M 100s Ch2
5.01V
Figure 11. Load Transient (10% to 90%) Step Response
215 Topaz Street, Milpitas, California 95035
3/6/2001
Figure 12. Line Transient (1Vpp) Step Response
Fax: (408) 263-7846 www.calmicro.com
(c) 2001 California Micro Devices Corp. All rights reserved. SmartORTM is a trademark of California Micro Devices Corporation.
Tel: (408) 263-3214
5
CALIFORNIA MICRO DEVICES
Typical Thermal Characteristics
Full Load Output Voltage (V)
CMPWR101
3.300 3.298 3.296 3.294 3.292 3.290 3.288 3.286 3.284 20 30 40 50 60 70
The overall junction to ambient thermal resistance (JA) for device power dissipation (PD) consists primarily of two paths in series. The first path is the junction to the case (JC) which is defined by the package style, and the second path is case to ambient (CA) thermal resistance which is dependent on board layout. The final operating junction temperature for any set of conditions can be estimated by the following thermal equation: TJUNC = TAMB + PD (JC ) + PD (CA ) = TAMB + PD (JA) The CMPWR101 uses a standard SOIC package. When this package is mounted on a double sided printed circuit board with two square inches of copper allocated for "heat spreading", the resulting overall JA is 85C/W. Based on maximum power dissipation of 0.43W (1.7V x 250mA) with an ambient of 70C the resulting junction temperature will be: TJUNC = TAMB + PD (JA ) = 70C + 0.43W (80C/W) = 70C + 37C = 103C Thermal characteristics were measured using a double sided board with two square inches of copper area connected to the GND pins for "heat spreading". Measurements showing performance up to junction temperature of 125C were performed under light load conditions (5mA). This allows the ambient temperature to be representative of the internal junction temperature. Note: The use of multi-layer board construction with power planes will further enhance the thermal performance of the package. In the event of no copper area being dedicated for heat spreading, a multi-layer board construction, using only the minimum size pad layout, will typically provide the CMPWR101 with an overall JA of 100C/W, which allows up to 0.5W to be safely dissipated.
Ambient Temperature (C)
Figure 13. Regulator VOUT vs TAMB (250mA Load)
4.18
Deselect Voltage Level (V)
4.16
4.14
4.12
4.10
4.08 25
50
75
100
125
Junction Temperature (C)
Figure 14. Deselect Threshold vs TJUNCT
0.36 0.34 0.32
Resistance ()
0.30 0.28 0.26 0.24 0,22 0.20 20 30 40 50 60 70
Ambient Temperature (C)
Figure 15. Switch Resistance vs Ambient Temperature
(c)2001 California Micro Devices Corp. All rights reserved. SmartORTM is a trademark of California Micro Devices Corporation.
6
215 Topaz Street, Milpitas, California 95035
Tel: (408) 263-3214
Fax: (408) 263-7846
www.calmicro.com
3/6/2001

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