CS30 STMICROELECTRONICS | Alldatasheet

Document overview

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  • PDF pages: 18

Technical content

Datasheet sections

  • 1 Application schematic and pin description
  • 2 Absolute maximum ratings and operating conditions
  • 3 Electrical characteristics
  • 3.1 Electrical characteristics curves
  • 4 Parameter definitions
  • 4.1 Common mode rejection ratio (CMR)
  • 4.2 Supply voltage rejection ratio (SVR)
  • 4.3 Gain (Av) and input offset voltage (V os)
  • 4.4 Output voltage drift versus temperature
  • 4.5 Output voltage accuracy
  • 5 Application information
  • 6 Package information
  • 7 Revision history

Features

  • Independent supply and input common-mode voltages
  • Wide common-mode operating range: 2.8 to 30 V
  • Wide common-mode surviving range: - 0.3 to

60 V (load-dump)

  • Wide supply voltage range: 4 to 24 V
  • Low current consumption: ICC max = 300 µA
  • Internally fixed gain: 20 V/V, 50 V/V or 100 V/V
  • Buffered output

Applications

  • Wireless battery chargers
  • Chargers for portable equipment
  • Precision current sources
  • Wearable

Description

The CS30 measures a small differential voltage on a high-side shunt resistor and translates it into a ground referenced output voltage. The gain is internally fixed. Wide input common-mode voltage range, low quiescent current, and tiny SOT23 packaging enable use in a wide variety of applications. The input common-mode and power supply voltages are independent. The common-mode voltage can range from 2.8 to 30 V in operating conditions and up to 60 V in absolute maximum rating conditions. The current consumption below 300 µA and the wide supply voltage range enable the power supply to be connected to either side of the current measurement shunt with minimal error. 3Vp Out Gnd Vm Vcc SOT23-5L (Plastic package) Pin connection (Top view) Table 1. Device summary

1 Application schematic and pin description

allows high-side current sensing at voltages much greater than the supply voltage (VCC). Figure 1. Application schematic the cover page and in Figure 1 above. Table 2. Pin description enters the shunt on the Vp side. exits the shunt on the Vm side.

2 Absolute maximum ratings and operating conditions

Table 3. Absolute maximum ratings

  1. Voltage values are measured with respect to the ground pin.
  2. Human body model: a 100 pF capacitor is charged to the specified voltage, then discharged through a

while the other pins are floating.

  1. Machine model: a 200 pF capacitor is charged to the specified voltage, then discharged directly between

connected pin combinations while the other pins are floating.

  1. Charged device model: all pins plus package are charged together to the specified voltage and then

discharged directly to the ground. Table 4. Operating conditions

3 Electrical characteristics

Table 5. Supply(1)

  1. Unless otherwise specified, the test conditions are T amb = 25°C, VCC =1 2V , Vsense =V p-Vm =5 0m V , Vm = 12 V, no load

Table 6. Input(1)

2.8 V < Vicm < 30 V

4.0 V < VCC < 24 V

  1. Unless otherwise specified, the test conditions are T amb = 25°C, VCC =1 2V , Vsense =V p-Vm =5 0m V , Vm = 12 V, no load
  2. See Section 4.1: Common mode rejection ratio (CMR) on page 12 for the definition of CMR.
  3. See Section 4.2: Supply voltage rejection ratio (SVR) on page 12 for the definition of SVR.
  4. See Section 4.3: Gain (Av) and input offset voltage (Vos) on page 12 for the definition of Vos.

Table 7. Output(1)

  1. Unless otherwise specified, the test conditions are T amb = 25°C, VCC = 12 V, Vsense = Vp-Vm = 50 mV, Vm = 12 V, no load on
  2. See Output voltage drift versus temperature on page 13 for the definition.
  3. Output voltage accuracy is the difference with the expected theoretical output voltage Vout-th = Av*Vsense. See Output

voltage accuracy on page 14 for a more detailed definition.

Table 8. Frequency response(1)

  1. Unless otherwise specified, the test conditions are T amb = 25°C, VCC = 12 V, Vsense = Vp-Vm = 50 mV, Vm = 12 V, no load on
  2. For stability purposes, we do not recommend using a greater value of load capacitor.

Table 9. Noise(1)

  1. Unless otherwise specified, the test conditions are T amb = 25°C, VCC = 12 V, Vsense = Vp-Vm = 50 mV, Vm = 12 V, no load on

3.1 Electrical char acteristics curves

Figure 2. Supply current vs. supply voltage Figure 3. Supply current vs. Vsense Figure 4. Vp pin input bias current vs. Vsense Figure 5. Vm pin input bias current vs. Vsense

Parameter definitions CS30

4 Parameter definitions

4.1 Common mode rejection ratio (CMR)

The common-mode rejection ratio (CMR) measures the ability of the current-sensing amplifier to reject any DC voltage applied on both inputs Vp and Vm. The CMR is referred back to the input so that its effect can be compared with the applied differential signal. The CMR is defined by the formula:

4.2 Supply voltage re jection ratio (SVR)

The supply-voltage rejection ratio (SVR) measures the ability of the current-sensing amplifier to reject any variation of the supply voltage VCC. The SVR is referred back to the input so that its effect can be compared with the applied differential signal. The SVR is defined by the formula:

4.3 Gain (Av) and input offset voltage (V os)

The input offset voltage is defined as the intersection between the linear regression of the Vout versus Vsense curve with the X-axis (see Figure 20). If Vout1 is the output voltage with Vsense=Vsense1=50mV and Vout2 is the output voltage with Vsense=Vsense2=5mV, then Vos can be calculated with the following formula: The amplification gain Av is defined as the ratio between output voltage and input differential voltage: CMR 20 – ΔVout SVR 20 – ΔVout Vos Vsense1 Vsense1 Vsense2– –= Av Vout Vsense

Figure 20. Vout versus Vsense characteristics: detail for low Vsense values

4.4 Output voltage drift versus temperature

maximum and minimum variation of Vout versus T. Figure 21. Output voltage drift versus temperature

4.5 Output voltage accuracy

  • the input offset voltage V os,
  • non-linearity

Figure 22. Vout vs. Vsense theoretical and actual characteristics with Av = 20 V/V for CS30A, Av = 50 V/V for CS30B and Av = 100 V/V for CS30C.

5 Application information

microcontroller, as shown in Figure 23. Figure 23. Typical application schematic

2.8 V to 30 V

6 Package information

specifications, grade definitions and product status are available at: www.st.com. ECOPACK® is an ST trademark. Figure 24. SOT23-5L package mechanical drawing Table 10. SOT23-5L package mechanical data

7 Revision history

Table 11. Document revision history