TS1109-20ITD833T

TS1109 Data Sheet TS1109 Bidirectional Current-Sense Amplifier with Buffered Bipolar Output The TS1109 incorporates a bidirectional current-sense amplifier plus a buffered bipolar output with an adjustable bias. The internal configuration of the TS1109 high-side current-sense amplifier is a variation of the TS1101 bidirectional current-sense amplifier, consuming 0.68 µA(typ) and 1.2 µA(max). The current-sense amplifier’s buffered output consumes only 0.76 µ A(typ) and 1.3 µA(max) of supply current. With an input offset voltage of 150 µV(max) and a gain error of 1%(max), the TS1109 is optimized for high precision current measurements Applications • Power Management Systems • Portable/Battery-Powered Systems • Smart Chargers • Battery Monitoring • Overcurrent and Undercurrent Detection • Remote Sensing • Industrial Controls silabs.com | Smart. Connected. Energy-friendly. KEY FEATURES • Low Supply Current • Current Sense Amplifier: 0.68 µA • IVDD: 0.76 µA • High Side Bidirectional Current Sense Amplifier • Wide CSA Input Common Mode Range: +2 V to +27 V • Low CSA Input Offset Voltage: 150 µV(max) • Low Gain Error: 1%(max) • Two Gain Options Available: • Gain = 20 V/V : TS1109-20 • Gain = 200 V/V : TS1109-200 • 8-Pin TDFN Packaging (3 mm x 3 mm) Rev. 1.0 TS1109 Data Sheet Ordering Information 1. Ordering Information Table 1.1. Ordering Part Numbers Ordering Part Number Description Gain V/V TS1109-20IDT833 Bidirectional current sense amplifier with buffered bipolar output 20 TS1109-200 IDT833 Bidirectional current sense amplifier with buffered bipolar output 200 Note: Adding the suffix “T” to the part number (e.g. TS1109-200IDT833T) denotes tape and reel. silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 | 1 TS1109 Data Sheet System Overview 2. System Overview 2.1 Functional Block Diagram Figure 2.1. TS1109 Bidirectional Bipolar Buffered Current Sense Amplifier Block Diagram silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 | 2 TS1109 Data Sheet System Overview 2.2 Current Sense Amplifier + Output Buffer The internal configuration of the TS1109 bidirectional current-sense amplifier is a variation of the TS1101 bidirectional current-sense amplifier. The TS1109 current-sense amplifier is configured for fully differential input/output operation. Referring to the block diagram, the inputs of the TS1109’s differential input/output amplifier are connected to RS+ and RS– across an external RSENSE resistor that is used to measure current. At the non-inverting input of the current-sense amplifier, the applied voltage difference in voltage between RS+ and RS– is ILOAD x RSENSE. Since the RS– terminal is the non-inverting input of the internal op-amp, the current-sense op-amp action drives PMOS[1/2] to drive current across RGAIN[A/B] to equalize voltage at its inputs. Thus, since the M1 PMOS source is connected to the inverting input of the internal op-amp and since the voltage drop across RGAINA is the same as the external VSENSE, the M1 PMOS’ drain-source current is equal to: I DS (M 1) = I DS (M 1) = V SENSE RGAINA I LOAD × RSENSE RGAINA The drain terminal of the M1 PMOS is connected to the transimpedance amplifier’s gain resistor, ROUT, via the inverting terminal. The non-inverting terminal of the transimpedance amplifier is internally connected to VBIAS, therefore the output voltage of the TS1109 at the OUT terminal is: ROUT V OUT = V BIAS − I LOAD × RSENSE × RGAINA When the voltage at the RS– terminal is greater than the voltage at the RS+ terminal, the external VSENSE voltage drop is impressed upon RGAINB. The voltage drop across RGAINB is then converted into a current by the M2 PMOS. The M2 PMOS drain-source current is the input current for the NMOS current mirror which is matched with a 1-to-1 ratio. The transimpedance amplifier sources the M2 PMOS drain-source current for the NMOS current mirror. Therefore, the output voltage of the TS1109 at the OUT terminal is: ROUT V OUT = V BIAS + I LOAD × RSENSE × RGAINB When M1 is conducting current (VRS+ > VRS–), the TS1109’s internal amplifier holds M2 OFF. When M2 is conducting current (VRS– > VRS+), the internal amplifier holds M1 OFF. In either case, the disabled PMOS does not contribute to the resultant output voltage. The current-sense amplifier’s gain accuracy is therefore the ratio match of ROUT to RGAIN[A/B]. For each of the two gain options available, The following table lists the values for RGAIN[A/B]. Table 2.1. Internal Gain Setting Resistors (Typical Values) GAIN (V/V) RGAIN[A/B] (Ω) ROUT (Ω) Part Number 20 2k 40 k TS1109-20 200 200 40 k TS1109-200 The TS1109 allows access to the inverting terminal of the transimpedance amplifier by the FILT pin, whereby a series RC filter may be connected to reduce noise at the OUT terminal. The recommended RC filter is 4 kΩ and 0.47 µF connected in series from FILT to GND to suppress the noise. Any capacitance at the OUT terminal should be minimized for stable operation of the buffer. silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 | 3 TS1109 Data Sheet System Overview 2.3 Sign Output The TS1109 SIGN output indicates the load current’s direction. The SIGN output is a logic HIGH when M1 is conducting current (VRS+ > VRS–). Alternatively, the SIGN output is a logic LOW when M2 is conducting current (VRS– > VRS+). The SIGN comparator’s transfer characteristic is illustrated in the figure below. Unlike other current-sense amplifiers that implement an OUT/SIGN arrangement, the TS1109 exhibits no “dead zone” at ILOAD switchover. Figure 2.2. TS1109 Sign Output Transfer Characteristic 2.4 Selecting a Sense Resistor Selecting the optimal value for the external RSENSE is based on the following criteria and for each commentary follows: 1. RSENSE Voltage Loss 2. VOUT Swing vs. Desired VSENSE and Applied Supply Voltage at VDD 3. Total ILOAD Accuracy 4. Circuit Efficiency and Power Dissipation 5. RSENSE Kelvin Connections 2.4.1 RSENSE Voltage Loss For lowest IR power dissipation in RSENSE, the smallest usable resistor value for RSENSE should be selected. silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 | 4 TS1109 Data Sheet System Overview 2.4.2 VOUT Swing vs. Desired VSENSE and Applied Supply Voltage at VDD Although the Current Sense Amplifier draws its power from the voltage at its RS+ and RS– terminals, the signal voltage at the OUT terminal is provided by a buffer, and is therefore bounded by the buffer’s output range. As shown in the Electrical Characteristics table, the CSA Buffer has a maximum and minimum output voltage of: V OUT (max ) = VDD (min ) − 0.2V V OUT (min ) = 0.2V Therefore, the full-scale sense voltage should be chosen so that the OUT voltage is neither greater nor less than the maximum and minimum output voltage defined above. To satisfy this requirement, the positive full-scale sense voltage, VSENSE(pos_max), should be chosen so that: V SENSE ( pos_max ) < VBIAS − V OUT (min ) GAIN Likewise, the negative full-scale sense voltage, VSENSE(neg_min), should be chosen so that: V SENSE (neg_min ) < V OUT (max ) − VBIAS GAIN For best performance, RSENSE should be chosen so that the full-scale VSENSE is less than ±75 mV. 2.4.3 Total Load Current Accuracy In the TS1109’s linear region where VOUT(min) < VOUT < VOUT(max), there are two specifications related to the circuit’s accuracy: a) the TS1109 CSA’s input offset voltage (VOS(max) = 150 µV), b) the TS1109 CSA’s gain error (GE(max) = 1%). An expression for the TS1109’s total error is given by: V OUT = VBIAS − GAIN × (1 ± GE ) × V SENSE ± (GAIN × V OS ) A large value for RSENSE permits the use of smaller load currents to be measured more accurately because the effects of offset voltages are less significant when compared to larger VSENSE voltages. Due care though should be exercised as previously mentioned with large values of RSENSE. 2.4.4 Circuit Efficiency and Power Dissipation IR loses in RSENSE can be large especially at high load currents. It is important to select the smallest, usable RSENSE value to minimize power dissipation and to keep the physical size of RSENSE small. If the external RSENSE is allowed to dissipate significant power, then its inherent temperature coefficient may alter its design center value, thereby reducing load current measurement accuracy. Precisely because the TS1109 CSA’s input stage was designed to exhibit a very low input offset voltage, small RSENSE values can be used to reduce power dissipation and minimize local hot spots on the pcb. 2.4.5 RSENSE Kelvin Connections For optimal VSENSE accuracy in the presence of large load currents, parasitic pcb track resistance should be minimized. Kelvin-sense pcb connections between RSENSE and the TS1109’s RS+ and RS– terminals are strongly recommended. The drawing below illustrates the connections between the current-sense amplifier and the current-sense resistor. The pcb layout should be balanced and symmetrical to minimize wiring-induced errors. In addition, the pcb layout for RSENSE should include good thermal management techniques for optimal RSENSE power dissipation. Figure 2.3. Making PCB Connections to RSENSE silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 | 5 TS1109 Data Sheet System Overview 2.4.6 RSENSE Composition Current-shunt resistors are available in metal film, metal strip, and wire-wound constructions. Wire-wound current-shunt resistors are constructed with wire spirally wound onto a core. As a result, these types of current shunt resistors exhibit the largest self-inductance. In applications where the load current contains high-frequency transients, metal film or metal strip current sense resistors are recommended. 2.4.7 Internal Noise Filter In power management and motor control applications, current-sense amplifier are required to measure load currents accurately in the presence of both externally-generated differential and common-mode noise. An example of differential-mode noise that can appear at the inputs of a current-sense amplifier is high-frequency ripple. High-frequency ripple (whether injected into the circuit inductively or capacitively) can produce a differential-mode voltage drop across the external current-shunt resistor, RSENSE. An example of externallygenerated, common-mode noise is the high-frequency output ripple of a switching regulator that can result in common-mode noise injection into both inputs of a current-sense amplifier. Even though the load current signal bandwidth is dc, the input stage of any current-sense amplifier can rectify unwanted, out-of-band noise that can result in an apparent error voltage at its output. Against common-mode injection noise, the current-sense amplifier’s internal common-mode rejection ratio is 130 dB (typ). To counter the effects of externally-injected noise, the TS1109 incorporates a 50 kHz (typ), 2nd-order differential low-pass filter as shown in the TS1109’s block diagram, thereby eliminating the need for an external low-pass filter, which can generate errors in the offset voltage and the gain error. 2.4.8 PC Board Layout and Power-Supply Bypassing For optimal circuit performance, the TS1109 should be in very close proximity to the external current-sense resistor, and the pcb tracks from RSENSE to the RS+ and the RS– input terminals of the TS1109 should be short and symmetric. Also recommended are surface mount resistors and capacitors, as well as a ground plane. silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 | 6 TS1109 Data Sheet Electrical Characteristics 3. Electrical Characteristics Table 3.1. Recommended Operating Conditions1 Parameter Symbol Conditions Min Typ Max Units 1.7 — 5.25 V 2 — 27 V System Specifications Operating Voltage Range VDD Common-Mode Input Range VCM VRS+, Guaranteed by CMRR Note: 1. All devices 100% production tested at TA = +25 °C. Limits over Temperature are guaranteed by design and characterization. Table 3.2. DC Characteristics1 Parameter Symbol Conditions Min Typ Max Units IRS+ + IRS– See Note 2 — 0.68 1.2 µA — 0.76 1.3 µA System Specifications No Load Input Supply Current IVDD Current Sense Amplifier Common Mode Rejection Ratio CMRR 2 V < VRS+ < 27 V 120 130 — dB VOS TA = +25 °C — ±100 ±150 µV –40 °C < TA < +85 °C — — ±200 µV VHYS TA = +25 °C — 10 — µV G TS1109-20 — 20 — V/V TS1109-200 — 200 — TA = +25 °C — ±0.1 ±0.6 % –40 °C < TA < +85 °C — — ±1 % TA = +25 °C — ±0.6 ±1 % –40 °C < TA < +85 °C — — ±1.4 % TA = +25 °C — ±0.6 ±1 % –40 °C < TA < +85 °C — — ±1.4 % ROUT From FILT to OUT 28 40 52.8 kΩ Input Bias Current IBuffer_BIAS –40 °C < TA < +85 °C — 0.3 — nA Input referred DC Offset VBuffer_OS — — ±2.5 mV Input Offset Voltage (See Note 3) VOS Hysteresis (See Note 4) Gain Positive Gain Error (See Note 5) Negative Gain Error (See Note 5) Gain Match (See Note 5) Transfer Resistance GE+ GE– GM CSA Buffer Offset Drift Input Common Mode Range Output Range TCVBuffer_OS –40 °C < TA < +85 °C — 0.6 — µV/°C VBuffer_CM –40C < TA < +85 °C 0.2 — VDD – 0.2 V VOUT(min,max) IOUT = ±150 µA 0.2 — VDD – 0.2 V Sign Comparator Parameters silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 | 7 TS1109 Data Sheet Electrical Characteristics Parameter Symbol Conditions Min Typ Max Units Output Low Voltage VSIGN_OL VDD = 1.8 V, ISINK = 35 µA — — 0.2 V Output High Voltage VSIGN_OH — — V VDD = 1.8 V, ISOURCE = 35 µA VDD – 0.2 Note: 1. RS+ = RS– = 3.6 V, VSENSE = (VRS+ – VRS–) = 0 V, VDD = 3 V, VBIAS = 1.5 V, FILT connected to 4 kW and 470 nF in series to GND. TA = TJ = –40 °C to +85 °C unless otherwise noted. Typical values are at TA = +25 °C. 2. Extrapolated to VOUT = VFILT. IRS+ + IRS– is the total current into the RS+ and the RS– pins. 3. Input offset voltage VOS is extrapolated from a VOUT(+) measurement with VSENSE set to +1 mV and a VOUT(–) measurement with VSENSE set to –1 mV; Average VOS = (VOUT(–) – VOUT(+))/(2 x GAIN). 4. Amplitude of VSENSE lower or higher than VOS required to cause the comparator to switch output states. 5. Gain error is calculated by applying two values for VSENSE and then calculating the error of the actual slope vs. the ideal transfer characteristic: For GAIN = 20 V/V, the applied VSENSE for GE± is ±25 mV and ±60 mV. For GAIN = 200 V/V, the applied VSENSE for GE± is ±2.5 mV and ±6 mV. Table 3.3. AC Characteristics Parameter Symbol Conditions Min Typ Max Units — 1.35 — msec — 3 — msec 0.4 — msec CSA Buffer Output Settling time tOUT_s 1% Final value, VOUT = 1.3 V Gain = 20 V/V Sign Comparator Propagation Delay tSIGN_PD VSENSE = ±1 mV VSENSE = ±10 mV — Table 3.4. Thermal Conditions Parameter Operating Temperature Range Symbol TOP silabs.com | Smart. Connected. Energy-friendly. Conditions Min Typ Max Units –40 — +85 °C Rev. 1.0 | 8 TS1109 Data Sheet Electrical Characteristics Table 3.5. Absolute Maximum Limits Parameter Symbol Conditions Min Typ Max Units RS+ Voltage VRS+ –0.3 — 27 V RS– Voltage VRS– –0.3 — 27 V Supply Voltage VDD –0.3 — 6 V OUT Voltage VOUT –0.3 — 6 V SIGN Voltage VSIGN –0.3 — 6 V FILT Voltage VFILT –0.3 — 6 V VVBIAS –0.3 — VDD + 0.3 V VRS+ – VRS– — — 27 V Short Circuit Duration: OUT to GND — — Continuous Continuous Input Current (Any Pin) –20 — 20 mA — — 150 °C –65 — 150 °C Lead Temperature (Soldering, 10 s) — — 300 °C Soldering Temperature (Reflow) — — 260 °C Human Body Model — — 2000 V Machine Model — — 200 V VBIAS Voltage RS+ to RS– Voltage Junction Temperature Storage Temperature Range ESD Tolerance silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 | 9 TS1109 Data Sheet Electrical Characteristics For the following graphs, VRS+ = VRS– = 3.6 V; VDD = 3 V; VBIAS = 1.5 V, and TA = +25 C unless otherwise noted. silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 | 10 TS1109 Data Sheet Electrical Characteristics silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 | 11 TS1109 Data Sheet Electrical Characteristics silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 | 12 TS1109 Data Sheet Electrical Characteristics silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 | 13 TS1109 Data Sheet Typical Application Circuit 4. Typical Application Circuit Figure 4.1. TS1109 Typical Application Circuit silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 | 14 TS1109 Data Sheet Pin Descriptions 5. Pin Descriptions TS1109 Table 5.1. Pin Descriptions Pin Label Function 1 SIGN Sign output. SIGN is HIGH for VRS+ >VRS– and LOW for VRS– >VRS+. 2 VDD External power supply pin. Connect this to the system’s VDD supply. 3 VBIAS 4 GND Ground. Connect to analog ground. 5 OUT CSA buffered output. Connect to CIN–. 6 FILT Inverting terminal of CSA Buffer. Connect a series RC Filter of 4 kΩ and 0.47 µF, otherwise leave open. 7 RS+ External Sense Resistor Power-Side Connection. 8 RS– External Sense Resistor Load-Side Connection. Exposed Pad EPAD Bias voltage for CSA output. When VREF is activated, leave open. Exposed backside paddle. For best electrical and thermal performance, solder to analog ground. silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 | 15 TS1109 Data Sheet Packaging 6. Packaging Figure 6.1. TS1109 3x3 mm 8-TDFN Package Diagram Table 6.1. Package Dimensions Dimension Min Nom Max A 0.70 0.75 0.80 A1 0.00 0.02 0.05 A2 b 0.20 REF 0.25 D D2 0.30 0.35 3.00 BSC 1.49 1.50 e 0.65 BSC E 3.00 BSC 1.51 E2 1.65 1.75 1.85 L 0.30 0.40 0.50 K 0.20 0.25 0.30 J 0.65 REF aaa 0.10 bbb 0.05 ccc 0.05 Note: 1. All dimensions shown are in millimeters (mm) unless otherwise noted. 2. Dimensioning and Tolerancing per ANSI Y14.5M-1994. 3. Recommended card reflow profile is per the JEDEC/IPC J-STD-020 specification for Small Body Components. 4. This drawing conforms to the JEDEC Solid State Outline MO-229. silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 | 16 TS1109 Data Sheet Top Marking 7. Top Marking Figure 7.1. Top Marking Table 7.1. Top Marking Explanation Mark Method Laser Pin 1 Mark: Circle = 0.50 mm Diameter (lower left corner) Font Size: 0.50 mm (20 mils) Line 1 Mark Format: Product ID Note: A = 20 gain, B = 200 gain Line 2 Mark Format: TTTT – Mfg Code Manufacturing code Line 3 Mark Format: YY = Year; WW = Work Week Year and week of assembly silabs.com | Smart. Connected. Energy-friendly. Rev. 1.0 | 17 Table of Contents 1. Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2. System Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2.1 Functional Block Diagram . . . . . . . . . . . . . . . . . . . . . . 2 2.2 Current Sense Amplifier + Output Buffer . . . . . . . . . . . . . . . . . . . . . 3 2.3 Sign Output . . . . . . . . . . . . . . . . . . . . 4 2.4 Selecting a Sense Resistor . . . . . . . . . . . . . . . . 2.4.1 RSENSE Voltage Loss . . . . . . . . . . . . . . . . . 2.4.2 VOUT Swing vs. Desired VSENSE and Applied Supply Voltage at VDD. 2.4.3 Total Load Current Accuracy . . . . . . . . . . . . . . . 2.4.4 Circuit Efficiency and Power Dissipation . . . . . . . . . . . 2.4.5 RSENSE Kelvin Connections . . . . . . . . . . . . . . . 2.4.6 RSENSE Composition . . . . . . . . . . . . . . . . . 2.4.7 Internal Noise Filter . . . . . . . . . . . . . . . . . . 2.4.8 PC Board Layout and Power-Supply Bypassing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 4 5 5 5 5 6 6 6 3. Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4. Typical Application Circuit . . . . . . . . . . . . . . . . . . . . . . . . . 14 5. Pin Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 6. Packaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 7. Top Marking. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Table of Contents 18 Smart. Connected. Energy-Friendly Products Quality Support and Community www.silabs.com/products www.silabs.com/quality community.silabs.com Disclaimer Silicon Laboratories intends to provide customers with the latest, accurate, and in-depth documentation of all peripherals and modules available for system and software implementers using or intending to use the Silicon Laboratories products. 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